• TABLE OF CONTENTS
HIDE
 Front Cover
 Abstracts of papers presented at...
 Additional sooty moulds in the...
 Effects on fungicides, nematicides...
 Evaluation of three nematophagous...
 Effect of custard-apple oil, neem...
 Assesment of losses caused by TMV...
 Assesment of losses caused by TMV...
 Phytopathological note: Incidence...
 Back Cover














Group Title: Journal of Tropical Plant Pathology
Title: Journal of tropical plant pathology
ALL VOLUMES CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00090520/00025
 Material Information
Title: Journal of tropical plant pathology
Series Title: Journal of tropical plant pathology.
Alternate Title: Journal of Philippine phytopathology
Philippine phytopathology
Physical Description: v. : ill. (some col.) ; 26 cm.
Language: English
Creator: Philippine Phytopathological Society
Publisher: Philippine Phytopathological Society
Place of Publication: Philippines
College Laguna
Publication Date: January-June 1982
Frequency: semiannual
regular
 Subjects
Subject: Plant diseases -- Periodicals -- Philippines   ( lcsh )
Plants, Protection of -- Periodicals -- Philippines   ( lcsh )
Genre: periodical   ( marcgt )
 Notes
Dates or Sequential Designation: v. 1, no. 1 (January 1965)-
General Note: Title from cover.
General Note: "Official publication of the Tropical Plant Pathology."
 Record Information
Bibliographic ID: UF00090520
Volume ID: VID00025
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 54382605
issn - 0115-0804

Table of Contents
    Front Cover
        Front Cover 1
        Front Cover 2
    Abstracts of papers presented at the twentieth annual meeting of the Philippine phytopathological society, Regent of Manila, Metro Manila, 5-8 May 1983
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
    Additional sooty moulds in the Phillipines
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
    Effects on fungicides, nematicides and herbacides on the growth of two nematophagous fungi
        Page 24
        Page 25
        Page 26
        Page 27
    Evaluation of three nematophagous fungi for the biological control of potato cyst nematode globodera rostochiensis compared with some nematicides
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
    Effect of custard-apple oil, neem oil, and mixtures on survival of nephotettix virescens and on rice tungro virus transmission
        Page 36
        Page 37
        Page 38
        Page 39
        Page 40
        Page 41
        Page 42
        Page 43
    Assesment of losses caused by TMV ordinary strain of flue-cured tobacco
        Page 44
        Page 45
    Assesment of losses caused by TMV ordinary strain on flue-cured tobacco
        Page 46
        Page 47
        Page 48
        Page 49
    Phytopathological note: Incidence of sugarcane rust (puccinia melanocephala H. & P. Sydow) in the Victorias Milling Company Disctrict, occidental negros, Phillipines in 1982
        Page 50
        Page 51
        Page 52
        Page 53
        Page 54
    Back Cover
        Page 55
        Page 56
Full Text




II MI We


rhytop


VOLUME 19 JANUARY






COt


Ithology


d JUNE 1983 NVMBERS4.1 2






ENTS


P-UbLIOULZO W1 FOPdcZ YFC IUCII C S VVOt L-L. LlS -lt-0SS I W.-k... IV L fI US|
Philippine Phytopathological Society, Regentof Manila, Metro Manila,
5-8 May 1983 ..................................... . 1-16

Additional Sooty Moulds in the Philippines Vichit Kriengyakul and
Tricita H. Quimio .................................. 17-23

Effects of Fungicides, Nematicides and Herbicides on the Growth of Two
Nematophagous Fungi Paecilomyces lilacinus and Arthrobotrys
cladodes Luciana M. Villanueva and R.G. Davide ............. 24-27

Evaluation of Three Nematophagous Fungi for the Biological Control of
Potato Cyst Nematode Globodera rostochiensis Compared with Some
Nematicides R.G. Davide and R.A. Zorilla. ................. 28-35

Effect of Custard-Apple Oil, Neem Oil, and Mixtures on Survival of Nepho-
tettix virescens and on Rice Tungro Virus Transmission V. Mariappan,
R.C. Saxena, and K.C. Ling. ............................. 36-43

Assessment of Losses Caused by TMV Ordinary Strain on Flue-Cured
Tobacco Luzveminda A. Revellame and Virgilio C. Ruguian...... 44-49

Phytopathological Note: Incidence of Sugarcane Rust (Puccinia melano-
cephala H. & P. Sydow) in the Victorias Milling Company District,
Occidental Negros, Philippines in 1982 R.J. Serra, F.C. Barredo
and A.P. Tiangco. ..................................... . 50-53


I














Official Organ of the Philippine Phytopathological Society, Inc.

BOARD OF DIRECTORS 1983-84



MR. FAUSTO L. NUQUE 0 President
MR. VALENTINO G. BALAOING 0 Vice-President
MISS LINA C. LAPITAN 0 Secretary
MR. FRANCISCO A. ELAZEGUI 0 Treasurer
MR. JOSE M. BANDONG 0 Auditor
DR. LINA L. ILAG 0 Ex-Officio Member
DR. DELFIN B. LAPIS 0 Board Member
DR. ROMULO G. DAVIDE 0 Board Member
DR. GIL G. DIVINAGRACIA 0 Board Member
DR. JOHN M. BONMAN 0 Board Member
DR. AVELINA D. RAYMUNDO 0 Board Member


EDITORIAL BOARD

ARCADIO J. QUIMIO 0 Editor-in-Chief
LINA L. ILAG Associate Editor
FAUSTINO T. ORILLO 0 Associate Editor

BUSINESS MANAGER
CEFERINO A. BANIQUED





SUSTAINING ASSOCIATES

American Cyanamid Company, Princeton, New Jersey, USA
Bayer Philippines, Inc., 622 Shaw Blvd., Mandaluyong, Metro Manila
Canlubang Sugar Estate, Canlubang, Laguna
Hijo Plantation, Inc., Tagum, Davao del Norte
Schering AG/Berlin, West Germany (Agrochemical Division) 5th Floor, Evekal Bldg., 855 Pasay Road
Makati, Metro Manila
Union Carbide Philippines, Inc., P.O. Box CCPO, Makati, Metro Manila
Victorias Milling Co., Inc. Victoria, Negros Occidental


good standing and Sustaining Associates. For c
copy elsewhere, postage free and payable in ad
Society Inc.: Information regarding members
Page Charge: The editorial board reserves the r
published page commensurate upon the payme
institutions. Advertisements: Rates may be se
any statement of claims made in advertisemi
Phytopathological Society, Inc.


t to charge some authors a present amount for eac
capabilities of their research projects or support
ed from the Business Manager. No endorsement ,
s is assumed by this Journal or by the Philippil









/


ABSTRACTS OF PAPERS PR ESE ft TETH
ANNUAL MEETING OF THE PHILIPPN-Pf O THEOLOGICAL
SOCIETY, REGENT OF MANILA, METRO MANILA
5-8 MAY 1983

Vascular-streak dieback of cacao. M.O. tium rolfsii, and Fusarium sp. in dryland
San Juan; Twin Rivers Research Center, and wetland fields. FA. Elazegui and
Madaum, Tagum, Davao delNorte. T.W. Mew; International Rice Research
Institute (IRRI), Los Bafios, Laguna.
Cacao trees affected with the vascular-
streak dieback (VSD) are now becoming a Damping-off caused by Sclerotium
familiar sight in cacao plantations in Min- rof has been common on mungbean
danao. The presence of the disease can be grown after wetland rice, while damping
seen through the characteristic yellowing gro after wead rice, ile damin
of one or two leaves on the second and off caused by Rhizoctonia solani and root
rot caused by Fusarium sp. affect grain
third flushes behind the growing tip. legume crops grown in strictly dryland
legume crops grown in strictly dryland
These chlorotic leaves develop with sharp- fields. Artificially infested legume stalks
ly defined green spots and the petioles buried in dryland and wetland fields were
show two or three tiny raised brown
show two or three tiny raised brown observed to have caused the mycelium of
spots at their basal ends. If splitted, a Fusarium i i i i
brown streak becomes visible after 25 to Fusarum to remain highly able in dry
30 seconds. The infected trees show a land conditions for months as compared
proliferation of axillary buds, shedding of to Sceerotium and Rhizoctonia where
immature leaves, together with a dying percent recovery dropped from 100% to
back of extremities and simulated cal- 0%. In wetland fields, all the three patho-
cium deficiency. Infected branches exhi- s had oor saprophytic survival;


causal fungus of VSD, a basidiomycete, is
Oncobasidium theobromae. The Amelo-
rado variety is the most susceptible. The
Malaysian hybrid cacao which is known
for its resistance to he cacao pod borer
is not spared from VSD. Other clones
such as UF10, UF12, UF49, R10, Pal21,
IMC 69 are also infected. Roguing of
young infected plants can slow down
the spread of the disease. Constant
pruning of infected chupens and branches
45 centimeters below the internal brown
streak are the standard practices in most
plantations. Others prune about the
length of a man's elbow to the heel of
the palm, beyond the infected branch.
Chemical control of VSD preferably with
a systemic fungicide may still be several
years away.

Survival of Rhizoctonia solani Sclero-


zocrona scierona were lower man inat oI
Sclerotium. The density of the three
pathogens in dryland fields was consistent-
ly higher than in wetlands. Fusarium was
most efficient in colonizing healthy
legume stalks, buried in both wetland and
dryland fields. Rhizoctonia colonized
more stalks than Sclerotium in dryland
fields. There was no colonization in wet-
land fields by the two pathogens. During
the subsequent months in both fields,
colonization percentage of the legume
stalk by the three pathogens was very
low. Sclerotium produced more sclerotia
than Rhizoctonia. Fusarium density in
dryland fields was higher.

Rice tungro virus complex in tungro-
resistant IR varieties. H. Hibino, E.R.
Tiongco and R.C. Cabunagan; IRRI, Los
Bafios, Laguna.








2 Philippine Phytopathology Vol. 19


The resistance of IR36, IR42, IR50, Grain Mold Nursery, International Sor-
IR54, and IR56 rice varieties was deter- ghum Variety Adaptability Trial and In-
mined by the mass screening and test ternational Sorghum Hybrid Adaptability
tube methods of inoculation using 1; 3 Trial, all from ICRSAT, India, were
and 5 insects per seedling. Percentage of screened for resistance to sorghum grain
seedling infection increased as the num- mold. Natural incoulum was provided.
ber of insects per seedling increased re- The causal organisms found were Curvu-
gardless of the inoculation method. Signi- laria sp., Fusarium sp., Phoma sp. and
ficant differences in the insects' life span Aspergillus sp. Of the 79 entries screened,
and high insect mortality during virus 3 brown seeded lines, IS-8848, UPLB
acquisition were obtained between the SG-5 (local check) and 67A x CS-174
test varieties. Percentage of tungro in- (local hybrid check) were found resistant;
fection was lower in the varieties where 9 were moderately resistant and the rest
insects' life span was shorter and insect were susceptible.
mortality was higher, but the varieties
where insects' life span was longer and in- Sources of resistance to tobacco mosaic
sect mortality was lower gave a higher virus (ordinary strain) in Nicotiana taba-
percentage of infection. cum L. L.A. Revellame and R.C. Carasi;
The presence of RTBV and RTSV in Philippine Tobacco Research and Train-
tungro-infected test varieties was deter- ing Center, Batac, Ilocos Norte.
mined by the latex agglutination test
using virus antisera and virus recovery test A total of 162 tobacco accessions
using the vector insect Nephotettix vires- composed of cultivars, local collections
cens. Regardless of time after inoculation, and stable hybrids were screened for res-
all plants sampled from susceptible con- instance to TMV-ordinary strain. This in-
trol TNI reacted to both RTBV and eluded 97 flue-cured, 35 cigar-filler/wrap-
RTSV. The sampling also showed that per, 23 Burley, and 7 Oriental tobacco
57.1%, 41.7% and 26.7%, of IR42, IR56, types. Of these accessions, 13 flue-cured,
and IR36 plants, respectively, reacted to 11 Burley and 1 Oriental tobacco types













ilacinus were conducted. The study
revealed that the number of root galls per
;root system of tomato var VC 11-1 was
educed. The range of reduction was from
15 to 87%. The yield was considerably
increased as a result of the fungal treat-
nent. Nemacur 10G applied at the rate
if 1 g/12 inch-diameter pots had lesser
fieldd than that of the P. lilacinus treat-
nent indicating some phvtotoxicitv of


um and Fusarium moniliforme. Pure cul-
ires of each pathogens were used in the
Allowing treatments to attain the above
objective: a) P. debaryanums, b) F moni-
forme, c) E. carotovora var. chrysantemi,
)P. debaryanum plusF. moniliforme and
) E. carotovora var. chrysantemi plus
moniliforme plus P. debaryanum. The
ouse and field conditions Under Rreen-


inducted in potato cyst infested areas in the mixed cultures of E. carotovora var.
ladaymen, Bugias. The first experiment chrysantemi, F moniliforme and P. debar-
'hich used Peruvian isolate ofP. lilacinus yanum (95.0 cm) did not vary signifi-
vealed that the fungus applied as tuber cantly with those caused by E. carotovora
ip and soil mix reduced the cyst popu- var chrysantemi (93.5 cm) or the mixed
tion resulting to an increase of 24.1% cultures of P. debaryanum and E. caroto-
Id 9.8% in yield as compared with the vora var. chrysantemi (85.1 cm) but signi-
rtreated, respectively. Nemacur 10G ficantly longer than those caused by P. de-
: the rate of 10 kg a.i./ha and Furadan baryanum (62.5 cm), F. moniliforme
G at 4.5 kg a.i./ha gave 81.2% to 146.6% (46.2 cm) or their mixture (41.6 cm). It
crease when the chemicals were incor- was observed that in all mixtures where
orated into the soil at planting time. It E. carotovora var. chrysantemi was
as observed in the second trial that the added, except when mixed with F. moni-
ingus including the Philippine isolate liforme (57.6 cm), the length of lesions
4o. 7)' applied as soil mix, tuber dip and produced were not significantly different
)mbined treatments reduced the cyst from each other. These observations sug-
apulation resulting to an increase of gest that synergism exists among these
tons/ha as compared to the control pathogens. Similar results were observed
untreated). The nematicides gave 50% to on experiments conducted under field
3.8% increase in yield. conditions except for the lesions pro-
duced which were relatively longer than
relationshipss among pathogens causing those developed under greenhouse condi-
talk rot disease complex on corn. T.C. tions.
ayacag and A. Soria; University of Assessment of yield loss due to sheath rot.
southern Mindanao (USM), Kabacan, B.A. Estrada, C.Q. Torres and J.M. Bon-
[orth Cotabato.
man; IRRI, Los Bafios, Laguna.
This study was conducted at the South-
rn Mindanao Agricultural Research Cen- An experiment was conducted in an
!r (SMARC), University of Southern irrigated field during the wet season of
lindanao (USM), Kabacan, North Cota- 1982 to assess rice yield loss due to
ato, to determine the relationship of the sheath rot and to determine the relation-
athogens, causing stalk rot. The corn ship between disease severity and some
plants exhibiting symptoms of stalk rot yield components. A rating scale (0 no
ere collected from the experimental infection; 1 slight infection; 2 mode-
elds of SMARC. The pathogens isolated rate infection; and 3 severe infection)
om the specimens were Erwinia caroto- was used for measuring the disease. Ran-
>ra var. chrysantemi, Pythium debarya- dom sampling of healthy and infected


al- u- IIIJ


------- -- ---r---








Vol.


panicles in each category of the disea
scale was made on four plots (each me
during 12.5 x 50 m) of IR442-2-58
susceptible breeding line). The influen,
of sheath rot on number, percentage
filled spikelets, and grain weight we
evaluated. To determine the fitness of tl
rating scale, data on flag leaf sheath i
fection, panicle exertion, grain filling ai
grain discoloration were also gather
Results of the study clearly demonstrate
the effect of the disease on each yie
component. The percentage of fill


levels of disease infection. Reductions
TC/ha were: 14%, 19%, 24% and 5(
with corresponding infection percent
of 25%, 50%, 75%, and 100%, respectii
ly. In PS/TC, highly significant reduction
at 50%, 75%, and 100% infection wi
corresponding losses of 29%, 41%, a
59%, respectively, were obtained. Loss
in PS/ha were 22%, 30%, 55%, and 75
at 25%, 50%, 75%, and 100% infectic
respectively.

Numerical analysis of phenotypic featui


tion in yield was observed with percentage and brown blotch isolates. F. Gossele
yield loss increasing with an increase in C.M. Vera Cruz, J. Swings, M. De Cleene
disease severity (scale 1 11.6%, 2 K. Kersters, J. De Ley and T.W. Mew
37.6%, and 3 98.7% yield loss). IRRI, Los Bafios, Laguna.

A numerical analysis of phenotypi,
Damage assessment of potato late blight. features and modem molecular method
J.S. Mariano, MJ. Ferrer and A.M. Cima- used in numerical taxonomy was applied
francia; Bureau of Plant Industry (BPI), on a series of 36 Xanthomonas campestri,
Baguio City. pv. oryzae, 12 Xanthomonas campestri,
pv. oryzicola and 6 brown blotch isolate
Field losses on potato due to late from different ecological and/or geo
blight Phytophthora infestans (Mont. de graphical origin. About 131 phenotypil
Bary) were assessed in Baguio Experiment tests were examined consisting of the fol
Station and Paoay, Atok, Benguet using lowing sets of tests: cell morphology (
two seedboard approved varieties namely, unit characters), biochemical test (26)
Cosima and Red Pontiac. The crops were acid from carbon sources (19), growth or
inoculated with the fungus at four dif- carbon sources (45), growth in different
ferent stages, namely 30, 45, 60 and 75 conditions (34) and reaction on carro
days after planting. Early infection result- and potato slices. The numerical analysis:
ed in tuber yield losses of 50.77% while of 131 phenotypic features showed three
yield losses with late infection ranged phenons. Phenon 1 was composed mainly
from 0.8-3.4%, depending on variety, of brown blotch isolates; Phenon 2, o:
location and weather conditions. X. c. pv. oryzae with strains NCPPE
and PXO61 clustering somewhat lowel
Yield loss estimates due to downy mildew tan te otr m ers of e os
of sugarcane caused by Peronosclerospora and Phenon 3, mostly of X. c. p. oryzi
sachhari (Miyake) C.G. Shaw. F.R. Hus- coaa with IRN 235, a X c. pv. oryza
millo, PHILSUCOM, La Granja, La Car- cola with IRN 235, a X. c. pv. oryza
lota City strain, NCPPB 1150 and NCPPB 1151, so
called X. c. pv. oryzae strains. There were
two subphenons within Phenons 2 and 3
Downy mildew of sugarcane tremen- Subphenons A and B in Phenon 2 could
dously reduced the yield of cane varieties not be differentiated clearly. Subphenor
Phil 56226 and Phil 58260 at varying C hydrolyzed arbutin and could grow ir









Abstracts of Papers


the presence of 0.0001% cadmium ace- (20,000 eggs and larvae/100 cc soil).
tate but subphenon D could not. Several Field observations indicated that the life
differentiating features were identified cycle in the growing season (April-July)
For the three phenons. The DNA base required approximately 70 days. Prelimi-
composition of the three organisms nary studies also suggest the presence of
revealed that the GC percent of brown the RO-1 pathotype.
blotch was within the span of the genus
Xanthomonas which could indicate that Observation on the reaction of promising
brown blotch might be a Xanthomonas. clones (1970-1979 series) to downy mil-
[n addition to numerical analysis of dew of sugarcane. T.S. Jereza. PHILSU-
phenotypic features, the method of poly- COM, La Granja, La Carlota City.
icrylamide gel electrophoresis (PAGE)
was applied using 6 strains of X. c. pv. Experiments were conducted to deter
oryzae and 5 of X. c. pv oryzicola. Three mine the resistance of susceptibility of
types of protein patterns were observed Phil clones to downy mildew of sugar-
tisually. No bacteriological characters cane caused by Peronosclerospora sac-
differentiated the physiologic races of chari. The method of infection was done
S e i r o by planting test clones in between rows
X. c. pv. oryzae strains based on pheno- o d ny mildew infected canes. A wee k
typi tesof downy mildew infected canes. A week
typic tests after planting the test cane, sweet corn
The effect of different factors on popula- seeds were planted within the test rows
tion development of the potato cyst to serve as additional source of infection.
nematodes in Benguet. R.A. Sikora, D.J. These were observed from the first to
Roettger, E.A. Verzola, T.A. Khayad. the sixth month after planting. Results
showed that out of the 510 clones tested,
Field surveys were conducted in co- 238 were found resistant to the disease;
operators' fields in 1981, 1982 and 1983 119 were moderate, and 153 were rated
to determine the frequency of occurrence susceptible.
md population densities of the potato
:yst nematode Globodera rostochiensis. Evaluation of sorghum germplasm for
A total of 541 fields were examined. Of resistance to tar spot and gray leaf spot
the samples taken from the different diseases. E.P. Paderes, S.C. Dalmacio and


5









Philippine Phytopathology


Yield loss assessment due to sugarcane
leaf scorch. R.D. Dosayla. PHILSUCOM,
La Granja, La Carlota City.

The sugar yield (PS/ha) of leaf scorch-
affected Phil 6111 was significantly re-
duced by 28.7% when infection was as
high as 88%. Other yield components
such as tonnage (TC/ha) and purity (PS/
TC) were also reduced by 22.2% and
7.6%, respectively, but the effect was not
significant. Agronomic characters like
diameter and length of stalk and number
of tiller per stool were likewise not af-
fected although differences were noted
between the diseased and control plants.
The percentage of stool affected in the
diseased plants was significantly higher
than the control.

Plasmodiophora brassicae (Woronin) af-
fecting crucifers in Benguet, D.J. Roett-
ger, E.A. Verzola and L.C. Ramirez; RP-
German Project, BPI, Baguio City.

A survey of cabbage fields in Benguet
and Mountain Province was undertaken.
Clubroot disease of crucifers, caused by
the soilborne fungus Plasmodiophora
brassicae (Woronin) was found to be a
serious problem in some fields in Atok,
Benguet. Bangao, Buguias was suspected
to be another affected area. All fields sur-
veyed in Mountain Province were free
from the disease, which was supposedly
spread by infected seedlings. Clubroot
disease has the potential to become a
limiting factor in cabbage production
under the conditions of the Northern
Luzon highlands with their acidic soils
and the short crop rotations used by
vegetable farmers.

Resistance of peanut cultivars to Cercos-
poridium personatum. R.A. Paningbatan
and L.L. Ilag. UPLB, College, Laguna.

Peanut resistance to Cercosporidium
personatum (Berk. and Curt.) Deighton,


the cause of blackspot, was characterized
using host genotypes with different levels
of resistance. PI 259747 and NC Acc
17133 (RF), confirmed to be resistant in
previous screenings, had remarkably re-
duced lesion number by 83%, compared
to susceptible CES 101 cultivar. The
lesions of C personatum in CES 101
increased in diameter by 1.3 mm/wk
which was over 2-fold faster than that of
PI 259747 with 0.5 mm/wk. The degree
of sporulation/lesion/wk in CES 101
(11.9 x 103) was 540% more than that in
PI 259747 (2.2 x 103).

Notes on the bacterial leaf stripe of coco-
nut. E.P. Rillo, R.G. Abad and E.C. Con-
cibido; Philippine Coconut Authority
(PCA), Guinobatan, Albay and Bago
Oshiro, Davao City.

Bacterial leaf stripe is a coconut malady
with wide distribution in the Philippines.
It is generally a disease of coconut palms
in the nursery stage up to 2 years old.
The disease is prevalent only during the
rainy season (September to January).
Outbreak of the disease can be con-
tained through timely application of
the bactericide Physan 20 at the rate of
32 grams per 3.78 liters of water at week-
ly to bi-weekly intervals. Further studies
are in progress.

Occurrence of Trichoderma in rice fields.
A.M. Resales and T.W. Mew; IRRI, Los
Bafios, Laguna.

Trichoderma sp. from different rice
fields at IRRI was detected by soil dilu-
tion plating using gallic acid agar medium.
Trichoderma can be isolated from dry-
land and rainfed fields but none from
wetland rice fields with standing water.
A great number of Trichoderma was
isolated from dryland fields previously
planted with mungbean. On PDA plates,
Thanatephorus cucumeris ceased to grow


Vol. 19









Abstracts of Paper


and Trichoderma eventually covered the Transparent polyethylene sheet was u
whole plate. Trichoderma frequently as seedbed cover which essentially ser
coiled around the aerial hyphae of T. cu- as mulch. Mulched soil had higher tern
cumeris, but there was no coiling around rature than bare soil at all depths, froi
sub-surface hyphae. There were three to 20 cm. Exposing the soil under cc
types of coiling observed: (1) numerous to direct sunlight even for just 5 days'
short branches produced by the main enough to raise the temperature to 4"
I...-- __ _. -, -1.. - I~ __ .- _II -


)und t]
a hypha


pathoge:
led arou


lation
tianae


,usarium oxysporu
s reduced even at


and (3) the Tricho- at 5 cm from 1.3 to 6.1 colonies per pla


with T -cJrucumeris h a a
with T. cucumeris hypha a


it intprvalc Dared to 9.3 colonies ner nlate at 5 c


LILUULU~U SlIIUIL ianicnes wnirn conii1 da


LIU IIUIII LU IU.0 CuOOniies er Dmalr


alvultu 111U jaLILu II b Iyp llyia. -i.wvl u[LauI 1Ii UlIc
mulching was found to be
Fungicide foilar sprays for soybean rust in controlling damping-(
control. D.B. Lapis and M.V.T. Neypes; mulching period was exte
UPLB, College, Laguna. days.

The effectiveness of Bayleton 25% Wp Preliminary study of iodih
at concentrations of 0.05, 0.10 and 0.15; cator of tungro disease of
Baycor 30% EC at 0.06, 0.12 and 0.18; mano, D.R. Pua, and E.1
and Dithane M-45 at 0.6 percentages of Region 4.
the formulated products were evaluated


bean rust compared with the unspray
checks. As concentrations of Baylet
and Baycor were increased, the sever;
of the disease correspondingly decrease
However, the number of pods and weigl
of seed of the different treatments c
not increase with rates although th
were much more than the check. T
effects of Bayleton and Baycor on dise;
control and yield were comparable wi
the standard fungicide, Dithane M-45.

Seedbed disinfestation by solar heatir
P.N. Dipon, S. Sugi, and H.L. Layaoe
PTRTC, Batac, Ilocos Norte.

The effectiveness of solar heating w
tested on seedbed naturally infested wi
damping-off during the months frc
November to January, 1982-83 at PTR1
Experiment Station, Batac, Ilocos Norl


as mdicator were evaluated under labo
tory conditions at RCPC Region 4. Ti
gro infected leaves were detected wh
treated with iodine after pigmentati
has been removed by soaking in dei
tured alcohol at different time duratio:
Boiling of infected leaves in denatur
alcohol likewise yielded positive reactic
Vague reaction was observed when
fected leaves were directly immersed
tincture of iodine.

Fungi as the cause of yellowing and oti
discolorations of rice grains. R. Quite
and L.L. Ilag; UPLB, College, Laguna.

The study was conducted to determi
the fungal species that cause yellow
and other discoloration of paddy aj
milled rice. Initial results showed th
inoculated paddy had a high percent
of chalky kernels. Yellowing was o


coiled
hyphi
the pi
a nar









Philippine Phytopathology


served in milled rice from paddy inocu- susceptible to both diseases was Hingu-
lated with Fusarium sp. and Aspergillus rakgoda. Rated susceptible to anthrac-
flavus Link ex Fr. Paddy inoculated with nose were Carrie and Peter Passand, and
Rhizopus.sp. had kernels that exhibited a to stem-end rot were Arumanis, Cheraku-
light yellowish brown color. Black kernels rasan, Edward, Joe Welch, Julie, Kensing-
were observed in milled rice from paddy ton, Otts, Pope, Tjenkir and Willard.
inoculated with Curvularia sp., Asper-
gillus terreus Thom, and A. ochraceus Influence of bacteria from paddy field on
Wilhelm. The yellowing obtained in this Thanatephorus cucumeris. A.M. Rosales
study was less intense compared to the and T.W. Mew; IRRI, Los Bafios, Laguna.
previous on-farm studies. This would pos- In wetland rice fields bacteria of dif-
sibly be due to the lower temperatures at- ferent colony types were isolated from
trained and less complex microbial inter- sclerotia of Thanatephorus cucumeris.
actions in the present study. The data Many of them exhibited antagonistic
indicate that the fungal species men- y o the ehibite antagistic
ii. s m- tivitv to the rice sheath blight fungus.


ion in paddy and milled rice. b ng of mycelial gro

'athologic reaction of twenty mango cul- gonistic effect of two sel
ivars to anthracnose and diplodia stem- isolates on survival of th
nd rot. A.N. Pordesimo, L.O. Namuco studied by soaking the scle
nd D.B. Mendoza, Jr.; UPLB, College, bacterial suspension at a co
1 x 106 cells/ml and incu
Laguna. under shake culture. Isola
Among 20 introduced varieties of duced completely the vi;
nango (Mangifera indica L.), only three, sclerotia in 2 weeks while hI
riz., Palmer, Siam, and Velei Columban the germination of sclerot
_-_- 'r-- A- U -------_ J --n ...


dioides Penz. and stem-end rot caused 1
Diplodia natalensis P. Evans, based
percentage of infected fruits and disea
index. None of their fruit samples e
hibited any discernible symptoms
either disease, 15 days after harvest. J
Welch was resistant only to anthracno:
Ah Ping and Zill were resistant only


bacterial isolates also prevented sheal
blight lesion development.

Enzyme linked immunosorbent assi
(Elisa) in potato seed certification. J.
Mariano, D.J. Roettger and N.Z. PosadE
BPI, Baguio City.


8









* Abstracts of Papers


F mungbean. I.F. Telan and D.B. Lapis; as possible means of control for grain dis-
PLB, College, Laguna. coloration. Weekly sprays of benomyl,
mancozeb, and chlorothalonil were
Bayleton 25% WP at concentration of applied seven times from early booting to
2.5, 125.0 and 187.5; Baycor at 90, 180 the early ripening stages. The incidence of
id 270 gram ai/ha were evaluated against seed discoloration was measured after
ercospora leaf spot with Benlate as harvest. Data on the severity of other
andard chemical. The results showed fungal diseases was also recorded. Despite
tat fungicide treatments at different a generally low level of infection by the
ncentrations effectively controlled the different fungus diseases, benomyl (50%
disease. Disease severity was effectively WP), applied at the rate of 1.0 kg formu-
duced and the number of pods and lation/ha/application was best in reducing'
eights of harvested seeds from chemical- seed discoloration. This was followed
treated plots were considerably in- by mancozeb (80% WP). Both chemicals
*eased as compared to those of the exhibited significantly lower grain dis-
)ntrol. coloration than the check. Benomyl
ant parasitic nematodes associated with also exhibited the best protection against
Igarcane in Negros Occidental and Panay narrow brown leaf spot (NBLS), followed
land. F.R. Husmillo, N.A. Selarde and closely by chlorothalqnil (75% WP); all
.D. Dosayla; PHILSUCOM, La Granja, 3 fungicides exhibited significantly lower
i Carlota City. disease severity than the check. Benomyl
Analyses of soil samples from 63 ha- showed significantly higher percent filled
endas belonging to 15 different mill dis- grains, together with chlorothalonil, and
cts showed the presence of 14 genera the highest yield increase over the check.
plant parasitic nematodes. Among Although all the chemical treatments
e 14 genera, Tylenchorhynchus was showed lower sheath rot and neck blast
e most predominant, followed by infection, the difference between treat-
elicotylenchus and Pratylenchus. Re- ments was not statistically significant.
rds showed that the highest popu- Effect of two fungicide sprays on neck
ion of Tylenchorhynchus was noted blast and sheath blight controlin the field.
Hda. Sta. Rita in the mill district of J.M. Bandong and B.A. Estrada; IRRI,
INEDCO with a count of 3,861/ Los Bafios, Laguna.
0 cc soil. Highest count of Helico-
fenchus (2,400) was noted in Hda. Natural infections by both blast and
inaman mill district of La Carlota while sheath blight were observed at the late
ztylenchus reached up to 1,420 in Hda. booting to early flowering stages on
n Enrique, mill district of Passi. IR52 rice variety grown in rainfed area at
temical control of seed discoloration in IRRI farms. Sprays were applied imme-
e. J.M. Bandong, S.D. Merca and J.M diately to the infected plants to deter-
nman; IRRI, Los Bafios, Laguna. mine the efficacy of the different combi-
nation treatments with 2 fungicides
Grain discoloration, caused by various against both diseases. Triphenyl tin ace-
ngi, poses a serious problem in process- tate or TPTA (60% WP), previously found
; "clean" seed for export by IRRI for effective against sheath blight, was com-
e by researchers in other countries. mon to all the treatments except the
ibstantial effort and money are spent to check. It was sprayed 2 to 3 days ahead
move discolored seeds from seed lots. of the other fungicides, i.e., edifenphos
tree fungicides were therefore evaluated (50% E.C.0, CGA49104 (50% WP) and


9









10


benomyl (50% WP), for neck blast con- that the Philippine isolates gave 72%-85%
trol to avoid the probable adverse incom- control, while the Peruvian isolate gave
patibility effect of mixing TPTA with any 90.58%-91% control. Studies on the in-
one of the other chemicals. Each fungicide fluencebf media, temperature, pH and
was applied 3 times at weekly intervals at light on the growth and sporulation of
the rate of 1.0 kg or liter formulated pro- P. lilacinus isolates showed that oatmeal
duct/ha/application. The results from the agar was the best medium for sporulation


me plants agauist necu oiast iuu mluuc-
rately effective protection against sheath
blight by any of the 32 fungicide com.
bined treatments as edifenphos-TPTA,
CGA49104-TPTA and benomyl-TPTA.
The best protection, as indicated by the
lowest neck blast and sheath blight infec.
tions, was provided by the edifenphos
TPTA followed closely by CGA49104
TPTA and benomyl-TPTA treatments. In
terms of percentage filled grains, the
highest was also exhibited by the edifen
phos-TPTA while the highest grain yield
was obtained from benomyl-TPTA fol.
lowed closely by the former and the
CGA49104-TPTA treatments.

Studies on Paecilomyces lilacinus anc
Arthrobotrys cladodes for the control ol
nematodes Globodera rostochiensis and
Meloidogyne incognita. L.M. Villanueva
UPLB, College, Laguna.

A total of 14 fungi were isolated from
M. incognita eggs and rabbit manure
Four of these were identified as Paecilo-
myces lilacinus (Thom.) Samson based or
their morphological characteristics. Thi!
fungus was found in the Institute of Plani
Breeding and Department of Plant Patho
logy, Los Bafios, Laguna; and Brgy, Punta
Calamba, Laguna. It was not found ir
eggmasses collected from La Trinidad
Benguet. All isolates of P. lilacinus were
capable of parasitizing M. incognita eggs
larvae, and adults. P. lilacinus isolate!
were also capable of significantly reducing
the egg hatching of root-knot nematode
A preliminary test on the use of P. lila
cinus isolates on the control ofM. incog
nita on tomato in the greenhouse showed


agar gave poor growth of the fungus. The
optimum temperature for all the isolates
was 200-300C, however, the best sporula-
tion occurred at 300C. In general, con-
tinuous darkness favored sporulation of
P. lilacinus. Results of the substrates
study revealed that the fungus could also
grow abundantly in sterilized mashed
potato, chopped water lily plants, fresh
and dried ipil-ipil leaves and corn grits. It
also grew moderately on rice hull and
coir dust. Dipping potato tubers in fungal
suspension for 10 minutes significantly
reduced nematode infection in potato
plants. No significant difference was ob-
served between different storage periods
(0-4 weeks). In general, spores are better
source of P. lilacinus inoculum than
mycelia. In the greenhouse test, only
water lily, coir dust and mashed potato
substrates showed increase of tuber
weight. With or without the fungus, all
the substrates tested caused significant
reduction on cyst nematode population
both in the roots and soil. Under field
conditions, all P. lilacinus isolates,
A. cladodes and chicken manure in-
creased the yield of potato. However,
nematicide Nemacur 10G at 10 kg/ha
gave significantly better control than
P. lilacinus.

Assessment of losses caused by TMV ordi-
nary strain on flue-cured tobacco cultivars.
L.A. Revellame and V.C. Ruguian;
PTRTC, Batac, Ilocos Norte.

The damage caused by TMV (ordinary
strain) on the growth, agronomic per-
formance and physical quality of four
flue-cured tobacco cultivars (Balikbayan,









Abstracts of Papers


MRS-3, NCBY and Coker 254) was eval-
uated. All four cultivars were systemati-
cally infected and showed the typical
green mosaic symptom within 10 days
after inoculation. Infected leaves were
small, misshapen, thick and brittle with
minute necrotic spots. In some cases,
mosaic burn appeared during the advance
stage of infection particularly from those
plants infected early. Cured leaves were
likewise brittle and thick, easily shattered
and had dark color. The time of inocu-
lating tobacco with the virus had signifi-
cant influence on plant height, leaf area,
cured yield and crop value but not on the
number of harvested leaves. When inocu-
lated at 15, 30, and 45 days after trans-
planting, the corresponding percentage of
losses compared to the healthy plants
were the following: average leaf area -
16.4, 32.2 and 22.8; cured yield 76.6,
26.8 and 34.4; grade index 73.4, 23.1
and 23.0; and crop value 92.5, 46.0 and
49.0. The response of all four cultivars to
infection followed similar trend. The
damage caused by the disease was greatest
in plants infected early and decreased as
infection was delayed. A reduction in
yield and crop value was attributed to the
deleterious effect of the virus on plant
growth, leaf weight, and physical quality
of cured leaves.

Comparative efficacy of fungicides in a
spray program against mango anthracnose.
J.M. Dangan and A.N. Pordesimo; UPLB,
College, Laguna. This study was con-
ducted at Villa Vicenta Farms, Tulay,
Ibaan, Batangas on 25 November 1980 to
23 April 1981.
Among the five market fungicides field-
tested against anthracnose, only captafol
39% 4F at 375 ml per 100 liters demons-
trated perceptibly the carry-over effect of
pre-bloom, bloom, and postbloom pro-
tectant fungicidal sprays on the develop-
ment of fruit anthracnose 12 days after
harvest. In general, fruits from unsprayed


mango trees had the highest percentage
(73%) of anthracnose and disease index
(1.7), while fruitsfrom trees sprayed with
fungicides had lower percentages (18% to
35%) of infection and disease indices (0.4
to 0.8).


Inheritance of resistance to tar spot. C.B.
Pascual, E.P. Paderes and S.C. Dalmacio;
UPLB, College, Laguna.

Crosses involving agronomically Accept-
able tar spot resistant and susceptible
lines/varieties (i.e. Ace. 2059 x UPLB
SG-5, Ace. 988 x 77 CSI, IS-84 x Ace.
3012 and BTx 624 x Acc. 3012) were
made and advanced to F2. F2 plants were
subjected to disease pressure and rated
individually for reaction to tar spot. F2
population showed a typical frequency
distribution curve and transgressive segre-
gation indicating that resistance is gov-
erned by polygenes.


Chemical control of common diseases of
rice. T.C. Bayacag and J.A. Soria; USM,
Kabacan, North Cotabato.

The effectiveness of four fungicides in
controlling rice blast, brown leaf spot,
and narrow brown leaf spot was evaluated
at Southern Mindanao Agricultural Re-
search Center (SMARC), University of
Southern Mindanao (USM), Kabacan,
North Cotabato. The chemicals that were
evaluated were Benlate 50 WP, 500 and
250; MBC 75 at 80, 165, and 333; Del-
sene MX 1,000; and Dithane M-45, 900
grams per hectare. Control check was also
provided.
The fungicides were applied twice, at
early flowering and heading stages. Dis-
ease index and yield were the bases in
evaluating the efficacy of the chemicals.
Benlate, at the rate of 500 grams per hec-
tare, was the most effective in controlling
rice blast, brown leaf spot, and narrow


Jan. & June 1983









Philippine Phytopathology


brown leaf spot. Delsene, MBC 75, and
Dithane M-45 showed comparable effects
with Benlate at 250 g/ha in controlling
rice blast. However, these fungicides did
not vary significantly in suppressing the
severity of brown leaf spot. MBC 75 at
the rates of 165 and 80 g/ha did not con-
trol narrow brown-leaf spot. The applica-
tion of fungicides significantly increased
the grain yield. Plots sprayed with Ben-
late at 500 g/ha gave the highest grain
yield at 6515 kg/ha or 41.41% higher
than the control. The lowest yield of the
sprayed plots was obtained from those
applied with Delsene at the rate of
1,000 g/ha with 5212 kg/ha or 13.2%
higher than the untreated plots. These
results clearly indicate that rice fields
sprayed with the above fungicides would
S greatly reduce the occurrence and
severity of infection of blast, brown leaf
spot, and narrow brown leaf spot.

Environmental influence of adult plant
resistance to bacterial blight. Z. Qi and
T.W. Mew; IRRI, Los Bafios, Laguna.

The adult plant resistance of Malagkit
Sungsong, Zenith, IR944, and IR1695
were studied in the greenhouse and
growth chamber at IRRI. Under the
greenhouse conditions, all these rices
were susceptible to races of Xanthomonas
campestris pv. oryze at the seedling or
maximum tillering stages. In general, they
become resistant when the plants grew
older. The expression of adult plant re-
sistance of the four rice varieties/lines is
related to leaf age and races. Malagkit
Sungsong showed resistant reaction to
race IV at the 18th leaf stage and to race
1 at the 11th leaf stage. In the growth
chambers, the adult plant resistance of
these rices was evaluated at three temge-
ratures, i.e., 33/21, 29/21, and 25/10 C.
On TN1 which is susceptible to the races
at all growth stages, lesion development
was fairly uniform at all temperature
ranges, except that the lesion develop-


ment progressed faster at 33/31 C than at
25/20 C. On IR1545 which is resistant to
races I, II, and III but susceptible to race
IV, the reactions remained quite stable as
compared to the reactions in the green-
house at all temperatures. The adult plant
resistance of Malagkit Sungsong and
Zenith was not affected by the change of
temperature although the resistance ex-
pression with respect to leaf age was dif-
ferent from that in the greenhouse. The
effect of temperature on resistant IR1695
and IR944 to the four races varied. The
resistance of IR1695 and IR944 to the
races in the growth chamber was quite
different from that under greenhouse
condition. The reactions were variable
and IR1695 became less resistant to races
I, III, and IV at the three temperatures
but remained resistant to race 11. At
25/20, IR944 was susceptible to races I,
III, and IV at all growth stages, but the
reactions were variable to race II. At
33/210C, the reactions to races I, III, and
IV were unstable.

Grain quality deterioration in on-farm
level of operation. M.E. Mendoza, A.C.
Rigor, Jr. UPLB, College, Laguna.

The study was conducted to determine
the nature and causes of grain quality de-
terioration at on-farm level of post-
harvest operation. The experiment in-
volved three systems: System I followed
the usual flow of on-farm practices; Sys-
tem 2 simulated the unavailability of
threshers, and System 3 simulated the un-
availability of dryers so that threshed
grains were immediately stored after
threshing. The effects of the different
systems on the quality of grains were ex-
tensively discussed. Findings revealed that
yellowing of the grain starts right on the
farm when threshing and drying opera-
tions were delayed. Yellowing was more
prevalent during the wet season.

Quantitative resistance of different rice


Vol. 19









Jan. & June 1983 -


cultivars to blast. E.J. Lee, F.L. Nuque,
J.M. Bonman and C.Q. Torres; IRRI, Los
Bafios, Laguna.

The quantitative resistance to blast,
sometimes called horizontal resistance,
was estimated for 175 GEU elite breeding
lines, Korean cultivars, and 18 varieties
known to have field resistance by mea-
suring rates of disease progress. Two sets
of experiments were conducted in one
square meter micro-plots in the blast
nursery. The number of lesions on 10
seedlings per cultivar was recorded two
weeks after seeding at 2-3 day intervals.
All data from lesion counts were con-
verted to number of lesions per 100 sq
cm of leaf area. The percentage of leaf in-
fection was further transformed to logits
and the apparent infection rate was mea-
sured using simple regression analysis.
Blast development and rate of increase
differed among the varieties and elite
breeding lines. Marked differences in
disease severity was observed as each ex-
periment progressed. Varieties exhibited
extreme variations in leaf blast severity.
Some were highly resistant, some mode-
rately resistant, and others very suscep-
tible. In the first experiment, IR36,
IR5931-110-1, Suweon 235 and IRI353
are some of the uninfected cultivars.
Varieties IR46, IR50 and line 21820-254-
3-3-2-2 developed blast infection very
slowly. Cultivars IRI 9672-155-2-1-3 and
IR442-2-58 had intermediate rates of
blast infection. On lines IRI 9670-263-3-
2-2 and IRI 9672-140-2-3-2-2, the rate
of blast infection was very rapid. Similar
results were obtained for the rate of blast
infection and disease severity in the
second experiment. Varieties IR56, IR
5929-12-3, IR5931-110, IR6023-10-1,
Suweon 3-4, IRI 353, and IRI 355 were
uninfected. As in the first experiment,
blast infection rates were very slow in
37-A, IRI 9743-40-3-3-2-3, but very
rapid in lines IRI9672-140-2-3-2-3 and
IR442-2-58.


Seed treatment for sclerotium seedling
blight control. J.M. Bandong and A.O.
Obusan; IRRI, Los Bafios, Laguna.

Sclerotium seedling blight, a disease
commonly encountered in seedbeds, da-
pog beds and direct seeded upland fields,
can cause substantial losses of seedlings
before transplanting and can seriously
reduce seedling stand in upland fields.
Sclerotial bodies of the causal fungus,
Sclerotium rolfsii, are sometimes mixed
with harvested seeds. Once the contami-
nated seeds are sown, the germinating
seeds and seedlings are attacked by the
pathogen. Using the "inoculum spreading"
method for evaluating the efficacy of
fungicides as seed treatment, carboxin
(75% WP), applied at the rates of 1.0 and
5.0 g and triphenyl tin acetate or TPTA
(60% WP) at 1.3 and 6.3 g formulation/kg
seeds, provided very effective protection
to the germinating seeds and seedlings. At
both rates of application for each chemi-
cal, no phytotoxic effect was observed
until two weeks after seeding.

Incidence of sugarcane rust in Hawaiian-
Philippiqe mill district in Negros Occi-
dental and suggested control measures.
F.R. Husmillo and C.S. Atienza; PHIL-
SUCOM, La Granja, La Carlota City.

Surveys on the extent of sugarcane
rust infestation in Hawaiian-Philippine
mill district in Negros Occidental were
conducted. Results showed that from the
total area of 1,764.05 ha surveyed,
1,170.15 ha or 67% was infested by the
disease; 15% of the area had severe in-
festation and 13% and 39% were rated to
moderate and slight infestation, res-
pectively, Microscopic examination of the
disease specimens collected from each
farm revealed that the species of rust pre-
dominant in the district was Puccinia
melanocephala H. and P. Sydow. It is
interesting to note that among the several
varieties planted in the district only Phil,


Abstracts of Papers









Philippine Phytopathology


56226 and B 43-62 ware severely infected
by the disease.
Studies onPyricularia oryzae race changes.
F.L. Nuque, J.M. Bonman and E.J. Lee;
IRRI, Los Bafios, Laguna.

Field studies in small blast nursery
plots using IR5533-PP854-1, Suweon 287,
and IRI 353 as test varieties and IR36,
IR8, TN1, and IR442 as inoculum spread-
er varieties were conducted at IRRI and
Sto. Tomas, Batangas to determine P.
oryzae race changes in time. The general
reactions (0-9) of each variety were re-
corded 25 days after every seeding. The
general reaction of the three test cultivars
did not change at IRRI during the period
of the experiment. However, at Sto.
Tomas, all three cultivars were generally
resistant at the start of the experiment,
but became susceptible later. IR 355
maintained its resistance throughout the
period, indicating that it has a broader
spectrum of resistance than the other two
varieties. A parallel experiment using 104
monosporial isolates collected periodical-
ly from lesions in the blast nursery at
IRRI was undertaken. The raes were
classified based on the reactions of the
Philippine, International, and new Japan-
ese differential sets. The prevalent races
belonged to the PD race group based on
the 12 Philippine differentials. Nine race
groups were identified based on the inter-
action between the isolates and the inter-
national differential varieties. The most
prevalent races were III-1, IG-1 and IB-45.
Studies on races in the blast nursery dur-
ing 1968-1969 showed that the most
prevalent races were IA-109 and IA-110.
In the present study, however, not a
single isolate of these two races was de-
tected. This indicates that there was a
race change in the blast nursery. Twenty
isolates did not infect any of the 8 inter-
national varieties although they were
capable of producing lesions on other
varieties. Based on the reactions of the


9 new Japanese differentials with known
R-genes, 42 pathogenic races were identi-
fied. Races 03, 403 and 447 were preva-
lent. Race No. 777 was the most virulent
among the races identified, since it could
attack all the varieties with all of the
Japanese differentials.

An epidemiological analysis of potato late
blight disease progress curve. A.B. Molina,
Jr. and Dr.R. Mackenzie; Penn State Uni-
versity, University Park, Pa, USA.

Epidemic analysis method was deve-
loped to accommodate periods of "non-
blight" weather using "severity values"
(SV) as "epidemiological time units."
Severity values are arbitrary values calcu-
lated from key environmental para-
meters. These indicate the likelihood of
late blight infection for a given day. The
cumulative SV's were used as the inde-
pendent variable in logit regression analy-
sis of disease progress curves. This change,
rather than the traditional days of the
Vanderplankain logistic models, permit-
ted improved resolution of disease pro-
gress curves over the two growing seasons
of highly variable weather. This proce-
dure is promising in distinguishing host
and pathogen characteristics in field ex-
periments that otherwise might be obli-
terated by changes in weather patterns
during growing seasons.

Effect of Custard-apple oil, neem oil, and
mixtures on survival of Nephotettix vires-
cens and on rice tungro virus transmission.
V. Mriappan, R.C. Saxena, and K.C. Ling;
IRRI, Los Bafios, Lagurta.

Custard-apple oil, neem oil, and mix-
tures were found to be effective in re-
ducing the survival of the green leafhop-
per N. virescens (Distant) and its trans-
mission of the rice tungro virus (RTV).
Mean percentages of insect survival and
RTV transmission to plants sprayed with
oils at 5, 10,20,30 or 50% concentration,


Vol. 19












16 Philippine Phytopathology Vol. 19


81 percent. Fruits of sweet clones are capable of high germination 76%-100%
more susceptible to the disease than when kept for one to three days in dry
fruits of sour clones. Under laboratory receptacle.
room conditions, the mature spores were













ADDITIONAL SOOTY MOULDS IN THE PHILIPPINES


n- OLU-U1L IIu nbUWVlaVC KTIV c
3afios, College, Laguna. The se
;riculture, Institute of Technok

Ph.D. thesis of the senior auth
Is.

ABSTRACT


, icspecuveiy. ur
ir author is prese
, Tungsong (Sai-Y

University of the


li rmou UoIl uous uxnijonl


trichophila on Eris botrj
xyphium sp. on Ficus u,
--_ -A n-


. on ixora, rlumeria, (
japonica, Ireneopsis
oifolia and Sorghum


In a previous paper (Kriengyakul and cies identified based on the latest taxono-
luimio, 1983), the authors had reported mic concepts of the group. As indicated
ine species of sooty mpulds collected in in the previous paper, identification was
ie Philippines from leaves and fruits of based largely on Hughes' (1976) general
)me major and minor fruit crops. These concepts of the sooty molds and on Batis-
,ecies were: Chaetothyrium anonicola ta and Ciferri's (1962) and Hansford's
n Anona muricata (guayabano) and A. (1961) keys on Chaetothyriales and Me-
!uamosa (atis); Tripospoermum sp. on liolales, respectively. Notes were also
rtocarpus heterophylla (langka); Ante- made referring to Reynolds' series of
ztula trisepta and Meliola citricola on papers on foliicolous ascomycetes (Rey-
itrus spp.; Chaetothyrium quaranticum nolds, 1979, 1982) following his latest
r Lansium donesticum (lansones); Me- concepts on the taxonomy of plant sooty
Ola mangifera on Mangifera indica molds.
nango); Phaeochaetia psidii on Psidium
rajava (guava); and Chaetothyrium I. Asterdiella rubi (Stev. & Rold.) Hansf.
'zigii and Phaeochaetia syzigii on Syzi- Sydowia 10:50. 1957. Irenina rubi Stev.
urn communi (chico). & Rold., Philipp. Jour. Sci. 56:57. 1935.
It has been observed that one host can (Fig. 1).
Infected with 2 or more species of the
ioty mold or one sooty mold species can Colonies black, epiphyllous, circular,
feet 2 or more different hosts. While a up to 3 mm in diameter, velvety, thick,
w of these genera had earlier been scattered on the leaf surface. Hyphae
ported but of different species, all the brown to reddish brown, substraight,
iove, with the exception of Meliola branching opposite at wide angles, loosely
angifera, were described and reported reticulate, hyphal cells cylindric, 14.67-
r the first time in the Philippines. 20.54 u long, and 7.33-8.80 u broad.









18 Philippine Phytopathology Vol


17.60 u long; stalk cells cylindric or to brown, 14.67-19.07 u x 20.54-23.4
cuneate, 3.67-5.13 u long; head cells sub- (Class Coelomycetes, Order Sphaerc
globose to globose, 11.00-11.74 u long, dales, Family Sphaeropsidaceae).
and 11.74-13.20 u broad. Mucronate hy- On leaves of Capparis micracantha I


14.67-17.60 u long and 5.87-8.80
broad. Perithecia blackish-brown, globos
few, slightly verrucose, 148.57 u in diar
surface cells to 9.97 in high. Spor
brown, few, oblong, obtuse, 4-septat
14.67 u x 32.27-35.21 u, slightly co
stricted at septa. (Class Pyrenomycete
Order Meliolales, Family Meliolineae).
On leaves of Rubus faxinifolium Poi
Banaue, Ifugao province, Philippines, D
cember 24, 1982. CALP No. 8464.
Asteridiella differs from Meliola
that it does not form mycelial sete
while it differs from Irenopsis which do
not also form mycelial setae, in that t
latter bears perithecial setae. Other th
the above, the 3 genera which all belo:
to Order Meliolales, can easily be m
taken with one another.
Stevens and Roldan (1935) report
the type species on Rubus rosaefolium
the Philippines as Irenina rubi.

II. Asterostomella horrida Bat. & Ma
Bat. & Cif. 1959. Mycopathologia 11:
(Fig. 2).

Mycelium dark brown to black, e
phyllous, superficial, nearly covering 1
whole leaf surface. Hyphae slightly brov
cylindric, straight, cylindrical cells, 2.'
4.40 u x 14.67-26.41 u, branching alt
nate at wide angle. Capitate hyphopo,
opposite or alternate, cylindric, strain
and or bent, 10.27-14.67 u long; stalk c
short, straight, cylindric, 2.93-5.87 u
2.93-4.40 u; head cell oblong, cylindi
straight or bent, rounded end, 7.33-11.
u x 5.28-5.87 u. Mycelial setae no
Perithecia none. Pycnostromas d&
brown, shield like, numerous 82.
108.56 u in diam with 4-8 conidia. Pyc
diospores subglobose to oval, dark bro


This species is the imperfect stage (
Asterina capparidis Syd. & Butl. It w;
first reported in 1914 on Capparis hon
dea, Los Bafios, Luzon, Philippines (Bati
ta & Cifferi, 1959). Species are differed
tiated according to the size of pycnostre
mas and pycnidiospores.

III. Balladyna velutina (Berk. & Curt
Hohn., Boedijn. 1961. Persoonia 1(4
398 (Fig. 3).

Colonies black, amphigenous, circula
up to 2 mm in diam, scattered on the le;
surface, mostly epiphyllous, crowd
confluent, and then covering the who
leaf surface. Hyphae brown, cylindri
5-28-5.87 u broad, branched, septate
hyphal cells straight, 14-67-1907 u Ion
Hyphopodia alternate and lateral, 1-celle
lobed, 8.22-8.80 u. Mycelial setae dal
brown, numerous, septate, acuminate, o
tuse, 44-114.43 u long, 8.22-8.89 u bro;
at the base, 2.93-3.52 u at the top. Pe
thecia brown, subglobose, 49.88-70.42
high, 49.88-61.61 u broad, contain
asci with 8 subglobose, ascoporn
29.33-32.27 u in diam. Ascospores gra
ish brown to brown, 2-celled, oblor
constricted at septum, 14.67-20.54 u
7.92-9.39 u. (Class Loculoascomycett
Order Dothideales; Family Parodi6psid
ceae).
On leaves of Gardenia florida Lini
Zamboanga del Norte, Mindanao Islan
Philippines. September 1981. CALP N
8466.
Teodoro (1937) recorded this spec:
on Gardenia sp. in Laguna, Palawan, I
taan, and Rizal in the Philippines. T
present collection came from Zamboan
del Norte.









il Sooty Moulds in the Phili


IV. Chaetothyrium clavatisporum (Syd.)
Hansf. 1946. Comm. Mycol. Inst. Mycol.
Papa. No. 15, p. 150 (Fig. 5).
Mycelium dark brown, epiphyllous,
pelliculose, superficial on the leaf surface.
Hyphae hyaline to subhyaline, constricted
at septa; hyphal cells 4.40-5.68 u x 8.07-
14.67 u. Mycelial setae black, 182.87-
365.71 u long. Perithecia black, setose
with erect setae 91.42-102.86 u long and
8.00-85.71 u broad at the base. Asci hya-
line, subclavate, 14.67 x 32.27 7, 8 asco-
pores, aparaphysate. Ascopores hyaline,
clavate, slightly constricted at septum, 3
septate, 5.13-6.16 u broad and 23.47-
26.41 u long (Class Loculoascomycetes,
Order Dothideales, Family Chaetophyria-
ceae).
On leaves of xora coccinea Linn., Los
Bafios, Laguna province, Philippines. Au-
gust 1980. CALP 8471.
This species was reported on Ixora,
Psidium, Acrostichum in the Philippines
and identified as Aithaloderma clavatis-
poum by Sydow in 1913. Batista and
Ciferri (1962) reported that the descrip-
tion of Phaeochaetia clavatispora (Syd.)
Bat. & Cif. n. comb. agrees with that
original description of Sydow.

V. Conidiocarpus sp. Woronichi: Hughes.
1976. Mycologia 68:725 (Fig. 5).

Mycelium black, epiphyllous, pellicu-
lose, thick, velvety, covering the whole
leaf surface. Hyphae pale brown, cylin-
dric, septate, slightly constricted at septa;
hyphal cells 5.28-5.57 u x 5.86-17.60 u.
Pycnidia reddish brown to dark brown,
194.28-434.38 u high, composed of tight-
ly compacted, anastomosed, synnematous
cylindrical hyphae with long narrow cy-
lindrical stalks, 17.14-22.86 u broad, and
194.28 u long (more or less) swollen
above the middle to 28.57-34.29 u broad,
and 114.29 u long, with 11.43-13.71 u
broad, and 114.29 u long (more or less)
at the neck, terminate in an ostiole fringed
with hyaline, subulate, hvohal extensions.


Conidia hyaline, globose to slightly ellip-
soid, about 0.88-2.93 u in diam. (Class
Coelomycetes, Order Sphaeropsidales,
Family Sphaeropsidaceae).
On leaves of Ixora coccinea Linn., Da-
gupan City, Pangasinan province, Philip-
pines. January 1982. CALP No. 8481.
On leaves ofPlumeria acuminata Ait.,
Dagupan City, Pangasinan province, Phil-
ippines. January 1982. CALP No. 8481.
On leaves of Chrysophyllum cainito
Linn., Bontoc, Mountain Province, Philip-
pines. November 1982. CALP 8483.
On leaves of Fiscus sp., Banaue, Prov-
ince of Ifugao, Philippines. December
1982. CALP No. 8424.
On leaves of Cocos nucifera Linn., Los
Bafios, Laguna province, Philippines. Sep-
tember 1980. CALP 8486.
This species appears to be common to
economic crop plants in the Philippines.
It is commonly found in the tropics and
subtropics where only conidial stage is
formed (Hughes, 1976). Yamamoto
(1954) showed that Conidiocarpus is the
conidial stage of Scoria or Phragmocaphias
and Hughes (1976) was certain of its cap-
nodiaceous affinity due to its capnodia-
ceous hyphae.

VI. Helicomina trichophila (Stev.) M.B.
Ellis; Ellis. 1976. More Dematiaceous
Hyphomycetes. Comm. Mycol. Inst. p.
179 (Fig. 6).

Colonies dark brown, hypohyllous,
velvety, circular, to 1 cm in diameter or
effuse on the leaf surface. Hyphae sub-
hyaline, cylindric, broad, hyphal cells
2.35-2.93 x 8.07-14.67 u. Conidiophores
pale brown, loosely branched, septate,
20.54-117.36 x 3.23-4.11 u, with nume-
rous prominent cylindrical or conical den-
tates. Conidia pale brown, straight,
curved or flexous, 3-8 septate, 3.81-5.87
u x 58.68-79.22 u. (Class Hyphomycetes,
Order Moniliales, Family Dematiaceae).
On leaves of Eriobatrya japonica
(Thumb.) Lindl.).. Sagada, Mt. Province.


19









Philippine Phytopat]


Philippines. November 1982. CALP I
8487.
Ellis (1976, 1980) reported only 3 s
cies of Helicomina and the present sp(
men resembles closest H. trichopi
based on size of the conidia. In a rec
paper, Quimio and Abilay (1982) 1
reported and described unknown spec
of Helicomina on grape leaves in the P1
ippines but this appears to be disti
from the present collection based on
size of the conidia.

VII. Irenopsis penguetensis Stev. & Ro
Philipp. Jour. Sci., 56:39. 1935 (Fig.

Colonies black, circular, thin, velve
to 9 mm in diam, amphigenous, mos
epiphyllous, scattered on the leaf surfa
Hyphae pale brown to blackish bros
sinous to crooked, branching altern,
hyphal cells 14.67-35.21 ux 7.33-8,8C
Capitate hyphopodia brown, alterns
straight or bent, entire 20.54-30.81
long and 11.74-14.67 u broad; stalk c,
long, straight, cylindric, 8.80-23.47 1
8.07-8.80 u; head cells subglobose
angulose, 14.67-17.60 u x 11.74-14.6'
Mucronate hyphopodia pale brown
brown, ampuliform, separate or alternm
entire 16.14-23.47 u x 8.80-11.00 u. P
thecia blackish brown, globose, few,
142.86 u in diam, perithecia black
brown, globose, few, to 142.86 u in di,
perithecial setae 7-9, dark brown, ern
straight or bent, apex obtuse, 160 1
8.80 u, 3-5 septate. Spores brown, cy
dric, obtuse, 4-septate, to 44.01 u 1(
and to 17.60 u broad, constricted
septa. (Class Pyrenomycetes, Order Me
lales, Family Melilineae).
On leaves of Ficus irisana Elm.,
naue, Ifugao province, Philippines. Dec(
ber 1982. CALP No. 8488.
Irenopsis differs from Asteridiella
that its perithecia are setose. I. being
tensis is the only species reported
Hansford (1961), and was first descril
and reported in the Philippines on sevi


species or ricus.

VIII. Leptoxyphium sp. Speg.; Hugl
S 1976. Mycologia 68:777-778.
F Mycelium black, epiphyllous, cru
t superficial, covering on the leaf surfai
hyphae brown, cells cylindrical, 3.,
s 5.57 u x 5.80-14.67 u, constricted at s(
S tum, with irregular network or int
woven on the upper surface of the le;
Synnemata produced from short hypl
(solitary hyphae), with helical twisting
the axis, the outer surface frequent
S brown pigmented, singly or frequent
proliferate through the fertile head
produce another conidiogenous apex a
S higher level; proliferations result in linE
series of up to 4 heads on a single fruc
fiction, about 285.70 u high, conii
hyaline continuous or 1-septate, ov
3.52-8.80 u x 2.93-5.87 u. (Class Hypi
mycetes, Order Moniliales, Family S
S bellaceae).
s On leaves of Ficus ulmifolia Lam., I
S Bafios, Laguna province, Philippin
S August 1981. CALP No. 8489.
On leaves of Sorghum bicolor I
S Bafios, Laguna province, Philippin
January 1982. CALP No. 8490.
Species of Leptoxyphium are wor
S wide in occurrence either as a compone
S of mixed effuse sooty molds on leaves
as pure colonies, localized, scatter
restricted or to aggregated grandular 1
comes on leaves (Hughes, 1976). Th
have been reported in North Ameri
S Thailand, India and Malaya.
t This genus may be confused w:
S Conidiocarpus but it differs in that
never forms a cavity where spores
formed. Conidia of Conidiocarpus a
remain hyaline and never form septa.

IX. Meliola hyptidis Syd. 1910. Ai
n Mycol. 8: 36 (Fig. 9).
/ Colonies black, circular, thin, velve
S up to 7 mm in diam., amphigenous, me
1 ly epiphyllous, numerous, scattered


zU









tional Sooty Moulds in the P


he leaf surface. Hyphae brown to reddish
)rown, undulate to crooked, branching
oppositee or irregular at wide angles,
iyphal cells cylindric mostly 19.07-29.34
Sx 5.13-7.33 u. Capitate hyphopodia
)ale brown to brown, subglobose, alter-
late, spreading or antrorse, usually
straight, 14.67-20.54 u long, stalk cells,
:ylindric or cuneate straight, 2.93-7.33
i long, and about 5.87 u broad; head cells
;lobose to ovate 11.74 u long and 10.27-
.1.74 u broad. Mucronate hyphopodia
)ale brown, alternate or opposite, ampul-
iform, entire 16.14-23-47 u x 7.33-8.80
i broad. Mycelial setae blackish-brown,
:ylindric, erect, or slightly curve, simple,
)btuse, some slightly swollen at apex,
\-12 septate, entire 171.43-240 u long,
i.60 u broad, mostly grouped around
)erithecia. Perithecia blackish-brown, glo-
iose, verrucose 137.14 u in diam. Spores
)ale brown, oblong, obtuse, 4-septate,
>.54-11.00 x 29.34-33.74, slightly con-
tricted at septa. (Class Pyrenomycetes,
)rder Meliolales).
On leaves of Hyptis rhomboidea Maet.
' bal., Banaue, Ifugao province, Philip-
pines. December 24, 1982. CALP No.
1495.
This species was previously reported
>n Hyptis suaveolens and H. capitata in
he Philippines (Hansford, 1961).

C. Triposporium sp. Corda; Ellis, 1971.
)ematiaceous Hyphomycetes. Common
V. Mycol. Inst. p. 136-137 (Fig. 10).

Colonies black, amphigenous, pellicu-
ose, thick, dense, covering the leaf sur-
'ace. Hyphae pale olivaceous brown to
)rown, hyphal cells 5.13-16 u x 11.74-
!2.87 u. Conidiophore macronematous
)rown, 111.49 u long, 5.87-7.63 u broad
it the base and 3.81-4.40 u at apex, foot
ellss 10.27-11.74 u long. Condia brown,
vith arms diradiate to tetraradiate arms,
usually triposporium type, each arm 2-5
eptate, slightly constricted at septa,
14.67-44.09 u long, 7.33-9.10 u broad at


he base and 2.93-3.52 u broad at apex.
Class Hyphomycetes, Order Moniliales,
familyy Dematiaceae).
On leaves of Ficus retusa Linn., Los
lafios, Laguna province, Philippines.
arch 1981. Associated with Scoleoxy-
'hium sp. CALP No. 8506.
Ellis (1980) described only 1 species,
"riposporium elegans, found on dead
iood and herbaceous stems in Europe
nd North America. The present collec-
ion appears to be similar in conidia size
o T. elegans.


LITERATURE CITED

IATISTA, A.C. and R. CIFERRI. 1959.
Sistematica Dos Fungos Imperfeitos de
Picnostromas Com Himenio Invertido.
Mycopathologia ET Mycologia Appli-
cata 11:1-102.
IATISTA, A.C. and R. CIFERRI. 1962.
The Chaetothyriales, Beheft, Sydowia
3:1-129.

:LLIS, M.B. 1976. More Dematiaceous
Hyphomycetes. Cambrian News Ltd.
Aberystwyth, Dyfed, U.K. 507 p.

iLLIS, M.B. 1980. Dematiaceous Hy-
phomycetes. 2nd reprint. Cambrian
News Ltd. Aberystwyth, Dyfed, U.K.
608 p.

IANSFORD, C.G. 1961. The Melioli-
neae. A Monograph. Sydowia Beih.
2:1-806.

IUGHES, S.J. 1976. Sooty moulds, My-
cologia 68:693-820.

:RIENGYAKUL, V. and T.H. QUIMIO.
1983. Sooty Molds of Some Major and
Minor Fruit Crops in the Philippines.
Phil. Agr. 66:270-281.

)UIMIO, T.H. and L.E. ABILAY. 1982.
Some unreported fungal genera and


21









.rnmuppme rnytopa


species in the Philippines. Phil. Agr.
(3):253-258.

REYNOLDS, D.R. 1979. Follicolous
comycetes: 3. The stalked capnoi
ceous species. Mycotaxon. 8: 417-4

REYNOLDS, D.R. 1982. Follicolous
comycetes: 4. The capnodiace
Genus Trichomerium Spegazzini
Emend. Mycotaxon. 14 (1): 189-2

STEVENS, F.L. and E.F. ROLDt

A











Fig. 1




Z-2








Fig. 3
Fig. 1. Asteridiella rubi: capitate hy
phodia (A), mucronate hypho
dia (B), ascospore (C).

Fig. 2. Asterostomella horrida: myce
with hypophodia (A), pycni
spores (B), pycnidia (C).


> 1~i. rnfippme MeIouneae. rnm
J. Sci. 56: 47-80.
S-
TEODORO, N.G. 1937. An Enum
tion of Philippine Fungi. Dept.
and Comm. Manila Tech. Bull. No
S-
s
YAMAMOTO, W. 1954. Taxonomic
). dies on the Capnodiaceae II. On
species of the Eucapnodiaceae. A
Phytopathol. Soc. Japan 19:1-5.












Lc
Fig. 2













Fig. 4
- Fig. 3. Balladyna velutina: mycelia (
0- mycelial setae (B), peritheci
(C).

!1 Fig. 4. Chaetothyrium clavatisporum:
mycelia (A), setose peritheci
(B), ascospores (C).


22









I booty mouas in tne mini L


Fig. 5 Fi
















Fig. 8 I

Fig. 5. Conidiocarpus sp.: synnematous
pycnidia (A), and pycnidiospores
(B).
Fig. 6. Helicomina trichophila: mycelia
(A), and conidia (B).
Fig. 7. Irenopsis benguetensis: capitate
and mucronate hypophodia (A &
B), perithecial setae (C), ascospores
(D).


Fig. 7
















9 Fig. 10

Fig. 8. Leptoxyphium sp.: synnematous
conidiogenous cells (A & B),
close-up of fertile head (C).

Fig. 9. Meliola hyptidis: hyphopodia (A),
ascospores (B), perithecium (C).


Fig. 10. Triposporium: mycelia (A), co-
nidia (B).


ZJ









Philipp. Phytopi


EFFECTS OF FUNGICIDES, I
ON THE GROWTH OF TV
PAECILOMYCES LILA CINUS )

LUCIANA M. VILLA

Respectively, former graduate stuck
of agriculture, University of the Philippir

Portion of the Ph.D. Thesis of the
Los Baflos, Philippines.

ABST
The growth of the nematophag
son and Arthrobotrys clatlodes Drechs,
agar medium (OMA) containing pesticide
These fungi failed to grow in OMA con
ssicol (PCNB) 75 WP at 100, 500 and 1(
Zincofol 50 WP, Daconil 75 WP, and
growth of P. lilacinus by 92-98% at 1I
M-45 at 1000 ppm reduced growth by oi
The fungicides Zincofol 50 WP
reduced the growth of A. cladodess by I
at 1000 ppm reduced growth by only :
growth in Dithane M-45 and Galben
exception of Difolatan, all the 10 fui
growth of both fungi at 100 ppm indic
concentration.
The nematicides Furadan 3G ai
70 WP and Afalon 50 WP slightly affec
at 100 and 500 ppm. However, at 1001
27-69%. As expected nematicides and
most of the fungicides tested.



The discovery of Paecilomyces lilacint
(Thor) Samson and Arthrobotrys cladt
des Drechs. as effective biological contr<
agent against root-knot and potato cy:
nemadoes has stimulated our interest t
study some of the ecological factors thi
may affect their growth in the soil. Ri
ports have indicated that the growth c
these fungi in culture can be affected b
pH of the medium, temperature, light an
different nutrient media (Jatala, 1981
Reyes and Davide, 1975; Villanueva an
Davide, 1984). It has been assumed thi
a number of pesticides applied to the so
could also affect their growth. This stud3
therefore, was primarily conducted t


EMATICIDES AND HERBICIDES
) NEMATOPHAGOUS FUNGI
ND ARTHROBOTRYS CLADODES

UEVA and R.G. DAVIDE

nt and professor of Plant Pathology, Colleg
5 at Los Bafios, College, Laguna.

enior author, University of the Philippines


ACT
is fungi, Paecilomyces lilacinus (Thom.) Sam-
as adversely affected when grown on oatmeal
particularly fungicides at high concentration.
ining Difolatan, Delsene MX 78 WP and Bra-
0 ppm, respectively. Other fungicides such as
Irzate M-50 WP also drastically reduced the
0 ppm, whereas Galben 45 WP and Dithane
y 41.5 and 68.3%.
Daconil 75 WP, and Curzate M-50 WP also
-97% at 1000 ppm. However, Captan 50 WP
.1%. The fungus also maintained substantial
i WP even at high concentration. With the
icides tested did not generally suppress the
ing that they can grow substantially at lower

Nemacur 10G and the herbicides Sencor
I the growth of P. lilacinus and A. cladodes
ppm the growth was reduced by as much as
rbicides were less toxic to both fungi than


determine the effects of some fungicide
nematicides, and herbicides on t1
growth of P. lilacinus and A. cladodes i
oatmeal agar medium.

MATERIALS AND METHODS

Fourteen pesticide chemicals which
included two nematicides, carbofura
(Furadan 3G) and phenamiphos (Nemi
cur 10G); 10 fungicides, captafol wit
Zn Cu (Zincofol 50 WP), Captan 5
WP, Captafol (Difolatan), PCNB (Brass
col 75 WP), Daconil 75 WP, Dithan
M-45, Delsene MX-78 WP, Ridom
35 WP, Curzate M-50 WP, and Galbe
45 WP; and two herbicides, metribuse
(Sencor 70 WP) and linuron (Afalo









SFungicides, Nematicides, &


0 WP) were tested at 100, 500 and 1000
ipm to determine their effects on the
rowth of P. lilacinus and A. cladodes
solates. About 6 ml of each concentra-
ion were poured into a sterile petri dish
before pouring the oatmeal agar medium.
our replicate dishes were provided for
ach concentration level. Isolates of P.
lacinus and A. cladodes were introduced
nto each dish in the form of 4-mm my-
elial disc placed at the center. Four petri
dishes containing OMA with no chemical
dded served as control for comparison.
After seeding, the petri dishes were
incubated at room temperature (27-290C)
or five days after which the fungus
rowth was determine by taking the dry
eight of the medium. The percentage
education in growth of the fungus per
treatment was determined based on the
control.

Fable 1. Effects of some fungicides, nematicides

Dry Weight (mg.) of Mycelia
TREATMENT
0 100 Reduction

ungicides:

Zincofol 50 WP 42.25 11.25 73.4
Captan 50 WP 55.50 15.00 72.9
Difolatan 52.25 0 100.0
Brassicol 75 WP 33.25 30.50 8.3
Daconil75 WP 56.00 38.25 31.7
Dithane M-45 35.50 21.50 39.4
Delsene MX-78 WP 58.00 6.50 88.8
Ridomil 35 WP 27.50 26.25 4.5
Curzate M-50-WP 37.00 4.00 89.2
Galben 45 WP 53.00 33.75 36.3

ematicides:

Furadan 3G 52.75 46.00 12.8
Nemacur 10G 54.50 48.25 11.5

herbicides:

Sencor 70 WP 62.00 38.50 37.9
Afalon 50 WP 6125 43.00 29.8

Data are means of 4 replicate plates taken from 5-day old cu


RESULTS AND DISCUSSION

The data obtained are summarized in
ables 1 and 2. Evidently all the pesti-
ides tested had varying effects on the
growth of P. lilacinus and A. cladodes
n oatmeal agar medium. The inhibitory
effect was more pronounced at 1000
ipm. As expected both fungi were more
sensitive to the fungicide than the nemati-
ides and herbicides. Out of the 10
ungicides tested only three showed com-
ilete suppression of growth of both
ungi. These were Difolatan, Delsene
4X-78 WP, and Brassicol (PCNB). Both
ungi failed to grow in Difolatan even at
00 ppm whereas in Delsene P. lilacinus
lid not grow in 500 ppm while A. clado-
les showed no growth at 1000 ppm.
however, both failed to grow in 1000
ipm of Brassicol.

id herbicides on the growth of P. lilacinus.

,rowth in 4 Concentrations'
% %
500 Reduction 1000 ppm Reduction



1.00 97.6 1.00 97.6
10.75 80.6 7.00 87.4
0.00 100.0 0.00 100.0
21.50 35.3 0.00 100.0
10.25 81.7 4.25 92.4
14.50 59.2 11.25 68.3
0.00 100.0 0.00 100.0
24.25 11.8 4.25 84.5
2.25 93.9 1.75 95.3
31.00 41.5 31.00 41.5



23.75 55.0 18.75 64.5
39.75 27.1 39.70 27.2



35.50 42.7 23.00 62.9
33.50 45.3 18.75 69.4

res of P. lilacinus.


25









Philippine Phytops


Table 2. Effects of some fungicides, nem;

Dr
TREATMENT
0 100

Fungicides:
Zincofol 50 WP 49.00 23.25
Captan 50 WP 59.50 52.50
Difolatan 49.50 0
Brassicol 75 WP 29.00 20.75
Daconil 75 WP 43.50 9.50
Dithane M-45 45.00 20.25
Delsene MX-78 WP 56.75 5.00
Ridomil 35 WP 44.25 17.00
Curzate M-50 WP 58.25 20.00
.Galben 45 WP 54.25 24.00
Nematicides:
Furadan 3G 46.75 36.00
Nemacur 10G 37.75 26.75
Herbicides:
Sencor 70WP 58.00 35.25
Afalon 50 WP 53.00 32.75

'Data are means of 4 replicate plates taken from

On the other hand, fungicide GE
45 WP at 1000 ppm gave the least e
on the growth of the two fungi; redi
the growth of P. lilacinus by 41.5%7
A. cladodes by 67.7%. At 1000
Dithane M-45, Ridomil and Captan
milder effects on growth of P. lila
compared to Curzate, Daconil and
cofol which were more toxic had
98% growth reduction. The least 1
fungicide to A. cladodes was Cal
followed by Dithane M-45 and Gal
On the other hand, Zincofol and Da,
at 1000 ppm greatly affected gr<
with 95-97% reduction.


ciaes, ana neroiciaes on tme growing o1 A. ctaaoaes.

eight (mg.) of Mycelial Growth in 4 Concentrations'
% % %
Reduction 500 Reduction 1000 ppm Reductio


52.55 3.25 15.21 1.50 96.93
11.76 42.75 28.15 36.25 39.07
100 0 100 0 100
31.56 0 100 0 100
78.16 6.25 85.63 2.00 95.40
55.00 18.75 58.33 16.00 64.44
91.18 2.75 95.15 0 100
61.58 17.00 61.58 8.50 80.79
65.66 14.25 75.54 7.25 87.55
55.76 20.50 62.21 17.50 67.74

22.99 18.25 60.96 16.25 65.24
29.13 23.50 37.74 20.50 45.69

39.22 27.25 53.01 22.50 61.20
38.20 30.25 42.92 23.50 55.66

day old culture ofA. cladodes.

)en P. lilacinus and A. cladodes were a
ect to substantially grow at 100 ppm of
ing nematicides but the growth inhibit
Lnd became more pronounced at 1000 p
pm with Furadan 3G being more toxic tl
Lad Nemacur 10G. Likewise, herbicides S
ius cor and Afalon had milder effects
in- growth of both fungi as compared w
)2- some of the fungicide treatments. So
xic of the effects were comparable with t
an, of the nematicides. At the highest rate
en. 100 ppm Sencor and Afalon reduo
inil growth of both fungi by 61-63% a
ith 56-69%, respectively.
P. lilacinus and A. cladodes apparer


26









Fungicides, Nematicides & 1


can grow at low concentration of tungi-
cides, nematicides and herbicides. The
results showed that both fungi were able
to maintain substantial growth in 100-
500 ppm of the pesticide tested except
for Difolatan, Delsene and Brassicol.
Mankau (1968) reported that certain
nematophagous fungi can utilize low
concentration of nematicides as carbon
sources. We found also that low con-
centration of Hostathion and DBCP
did not affect the growth of some nema-
tophagous fungi (Ruelo and Davide,
1978).
With these results it is possible to find
instances in the field where P. lilacinus
and A. cladodes become less effective
as biocontrol agents of nematodes due
to the presence of high concentration of
some of the above pesticides in the soil.
Heavy accumulation of Difolatan, Bra-
ssicol or Delsene in the soil could serious-
ly affect the growth of these fungi.

LITERATURE CITED

JATALA, P. 1981. Biological control of
Meloidogyne species: Methodology for
preparation and establishment of Pae-
cilomyces lilacinus for field inocula
tions. Proceedings, third Research
Planning Conference on Root-knot
Nematodes, Meloidogyne spp. July 20-
24, 1984. Jakarta, Indonesia.


MANKAU, R. 1968. Effect of nematicides
on nematode-trapping fungi asso-
ciated with the citrus nematodes. Pit.
Dis. Reptr. 52: 851-855.

REYES, T.T. and R.G. DAVIDE. 1975.
Fungi for biological control of plant
parasitic nematodes. Phil. Phytopathol.
Bull. No. 3.


RUELO, J.S. and R.G. DAVIDE. 1979.


Studies on the control of Meloidogyne
incognita. II. The effectiveness of
nematode-trapping fungi alone and in
combination with chicken manure and
Hostathion. Philipp. Agric. 62: 153-
158.


VILLANUEVA, L M. and R.G. DAVIDE.
1984. Effects of pH, temperature, light
and different nutrient media on the
growth and sporulation of a nemato-
phagous fungus Paecilomyces lilacinus.
Phil. Agric. In Press.


27









Philipp. Phyti


EVALUATION OF THREE I
BIOLOGICAL CONTROL
GLOBODERA ROST(
SOME

R.G. DAVII

Respectively, Professor, Departi
Crop Protection Center, College of
Bailos, College, Laguna.
Supported by a research grant f
of the Vegetable Pests Management Pr



The effectiveness of three nen
Samson, Gliocladium roseum Bainie
potato cyst nematode (Globodera ros
in Madaymen, Buguias in Benguet 1
both inoculation techniques. The ti
effect, were generally more effective
tion in P. Ulacinus treatments range
ranged from 22.5 to 41.9%. A. clad
only 20.5% reduction of cyst count a
Only the combined tuber dip
was comparable to the effects of tl
Isazofos (Miral 10G). All other fung
the two nematicides.
All the fungal treatments sho
the check. The yield increase frorn
36.5% as compared to 59.4% in ]
G. Roseum gave 22.9 to 32.4% yi
increase. All treatments also resulted
first and second class potato tubers.
Moreover, water lily applied
count by 16.8% in the third month
significantly better than the check.
INTRODUCTION

The potato cyst nematode Globot
rostochiensis Woll. in the Philippines
recent discovery. It is now seriously
fecting some potato farms in Mouni
Province and Benguet and is contint
to spread to other areas (Versola
Khayad, 1982; Zorilla and Davide, 191
To protect the potato industry, a series
studies have been conducted to deve
effective control measures against
nematode. Results of our previous stui
indicated that biological control thro
the use of nematophagous fungi sucl


LMAIUrtHAiUU UIN.Ul rUK ITHE
OF POTATO CYST NEMATODE
"HIENSIS COMPARED WITH
EMATICIDES

; and R.A. ZORILLA

nt of Plant Pathology and Researcher, Nati
riculture, University of the Philippines at

m the National Crop Protection Center as a
ram.

DISTRACT

ophagous fungi (Paecilomyces lilacinus (Thor.)
and Arthrobotrys cladodes Drechs.) against the
chiensis Woll.) on potato cv. Isola was evaluated
ivince using dip, soil mix and combination of
isolates of P. lilacinus, which gave comparable
lan G. roseum and A. cladodes. The cyst reduc-
rom 31.9 to 50.8% whereas those of G. roseum
es treatment, applied only as tuber dip, showed
he third month after treatment.
id soil mix treatment of P. lilacinus from Peru
nematicides phenamiphos (Nemacur 10G) and
treatments were significantly less effective than

d significant increase in yield as compared with
he P. lilacinus treatment ranged from 20.3 to
mnamiphos and 39.2% in isazofos treatments.
I increase while A. cladodes gave 20.3% yield
I higher percentage yield increase of marketable

soil mix without the fungus reduced the cyst
suiting to a yield increase of 12.1% which was

Paecilomyces lilacinus (Thom.) Sam
and Arthrobotrys cladodes Drechs. cc
a effectively control G. rostochiensis v
a effects comparable to some nematic
f- like carbofuran and ethoprop (David
n Zorilla, 1983; Villanueva, 1983). P.
g cinus has previously been reported
d Peru by Jatala et al. (1979) as effect
). against root-knot namatode Meloidog
if incognita and a potato cyst nemat
p Globodera pollida, while Arthrobo
e spp. and other nematophagous fungi f
s been reported by Reyes and Da
h (1975) to be effective against root-k
is nematodes M. incognita. Recently Ja









ion of Three Nematophagot


(1983 personal communication), re-
ported an isolate of a yellow fungus
which proved more effective against
potato cyst nematode than P. lilacinus.
The fungus was later identified as Glio-
cladium roseum Bainier by Mrs. Gloria
Molina of the National Crop Protection
Center, UPLB.
This study, therefore, was conducted
primarily to test the effectiveness of
G. roseum, P. lilacinus and A. cladoes
against G. rostochiensis in comparison
with the nematicides phenamiphos
(Nemacur 10G) and isazofos (Miral 10G).

MATERIALS AND METHODS

The experiment was conducted in a
potato farm severely infested with the
cyst nematode G. rostochiensis in Maday-
men, Buguias, Benguet province from
Septemberl27, 1983 to January 17, 1984.
A randomized complete block design
with four replications per treatment was
used. Each replicate occupied a 1 x 4-
meter plot. The distance between plot
was one half meter while the blocks were
one meter apart. Each plot was planted to
two rows of potato cv. Isola 30 cm apart.
Each row had 13 hills of potato making a
total of 26.
The nematophagous fungi tested wer
G. roseum, P. lilacinus and A. cladoes
while the nematicides were phenamiphos
(Nemacur 10G) and isazbfos (Miral 10G)
applied at 3 kg a.i./ha. The isolates of
P. lilacinus (one from Peru and the other
from the Philippines) were included in
the test. P. lilacinus and G. roseum were
applied as tuber dip, soil mix and the
combination of both tuber dip and soil
mix, while A. cladodes, due to limited
space, was applied only as tuber dip. For
the tuber dip treatment the potato seed
pieces or tubers were immersed for 10
minutes in the spore and mycelial suspen-
sion of the fungus previously cultured for
one week in oatmeal agar in Petri dishes.
To prepare the suspension, the agar cul-


ture was homogenized in waring blender.
with tap water for a few seconds. The sus-
pension contained approximately 5,000,
1,000 and 500 spores/ml of P. lilacinus,
A. cladodes and G. roseum, respectively.
G. roseum did not sporulate well on oat-
meat agar, hence, the low spore concen-
tration.

For the soil mix treatment, G. roseum,
P. lilacinus and A. cladodes were first
separately cultured in chopped, sterilized
water lily substrate in ball jars as they
sporulate very well on this substrate. Two
weeks later, 40-g culture of each fungus
was then added to each hill of potato just
before planting. For the combined treat-
ment, the potato tubers or seed pieces
previously dipped in the fungus suspen-
sion for 10 minutes were planted in the
soil previously mixed with 40 g of 2-week
old water lily culture of the 3 fungi. A
treatment of water lily alone was in-
cluded as control.

The nematicides phenamiphos (Nema-
cur 10G) and isazofos (Miral 10G) were
applied at 3 kg a.i./ha or at 13.3 g/4 sq.
m. or 0.5 g/hill of potato. Seedpieces not
treated with the fungus or nematicide and
planted directly into the nematode in-
fested soil served as check for comparison.

The population density of G. rosto-
chiensis was determined before and after
treatment at monthly intervals. In each
plot 400 cc composite soil samples were
taken at 8-15 cm deep from three
sampling sites. These samples were placed
separately in plastic bags and brought to
the nematology laboratory of the Depart-
ment of Plant Pathology for nematode
analysis. A subsample of 100 cc per repli-
cation was air-dried in Petri dishes for
two days and was later placed in a 500-ml
beaker filled with water and mixed tho-
roughly with a stirring rod to allow the
cyst to float. The cysts were then picked
uD and, counted under a dissecting micro-


90









Philippine Phytopa


,scope.
The yield data of each treatment r
cate were taken at harvest time.
tubers harvested were classified as
class, second class and third class.

RESULTS AND DISCUSSION
Effects on the population density'
G. rostochiensis. The data (Table 1) i
cate that all the fungal treatments sig
cantly reduced the nematode popular
in the soil as compared with the i
treated check. The reduction ranged i

Table 1. Pre- and post-treatment cou
potato cv. Isola as affected b




TREATMENT Pre-Treat-
ment2

P liacinus
Peru Isolate
Tuber dip 130.2
Soil mix 132.0
Combination 128.0
Phil. Isolate
Tuber dip 119.0
Soil mix 154.0
Combination 141.7
G. roseum
Tuber dip 124.2
Soil mix 117.0
Combination 129.0
A. cladodes
Tuber dip 131.5
Water lily (Soil mix) 129.5
Nematicide4
Phenamiphos 10G 141.0
Isazofos 10G 122.0
Check 140.7

1Data are means of four plot re:
significantly different at 5% level with
2Soil samples were taken just be
3Soil samples were taken at har
4Both nematicides were applied


22.5 to 50.8% at the third-month cou
li- However, P. lilacinus appeared more
ie fective than G. roseum and A. cladod
st though not significant in some cases.
Only the combined tuber-dip and so
mix treatment of P. lilacinus from Po
showed comparable effects with those
of phenamiphos (Nemacur 10G) and isa
i- fos (Miral 10G) at the second and th
i- month count. On the other hand, oi
n phenamiphos treatment significant
i- reduced cyst count one month after tre
n ment.

of cyst nematodes Globodera rostochiensis
he fungal and nematicide treatments1

st counts per 100 cc soil
Post-treatment
1st 2nd 3rd % Conti
mo. mo. mo.3



8.5 b 56.3 b 70.7 b 45.7
3.5 b 60.3 b 77.0 b 41.7
0.5 b 52.0 a 63.0 a 50.8

5. b 72.50 b 81.0 b 31.9
7.2 c 91.25 c 87.5 c 43.2
8.2 b 74.5 be 79.0 bc 44.2

0.5 c 81.0 be 86.3 cd 22.5
0.7 b 59.5 b 83.5 b 28.6
4.7 b 68.0 be 75.0 b 41.9

5.0 d 91.0 c 104.5 d 20.5
8.3 d 100.7 c 107.8 d 16.8

6.7 a 40.7 a 52.0 a 63.1
2.7 a 50.2 a 55.0 a 54.9
4.2 e 193.3 d 194.3 e -

:ates, means followed by the same letter are r
MRT.
re application of the different treatments.
;t time.
3 kg a.i./ha.


iO









n of Three Nematophaeous


Better control effects have been ob-
served in the combined tuber-dip and soil-
mix treatment of either P. lilacinus and
G. roseum than when the two treatments
were separately applied. This indicates
that increasing the population density of
P. lilacinus in the potato tubers as well as
in the soil also improved the biological
control effectiveness of the fungus.
Although the two isolates of P. lilacinus
generally gave comparable effects in the
tuber-dip treatment, the Philippine isolate
was relatively less effective than the Peru
isolate in the soil-mix and the combined
treatment. The highest percentage control
by the Peru isolate was 50.8% in the com-
bined treatment while the Philippine
isolate had 44.2% control. The effective-
ness of these isolates may be further im-
proved by increasing the spore density
both in tuber dip and soil mix applica-
tions as well as by two or three additional
soil application during the growing period
of potato.
The effect of G. roseum on the cyst
nematode reduction was relatively lower
than P. lilacinus but in some cases the dif-
ference was not significant. Likewise, cyst
count in A. cladodes tuber dip treatment
was significantly higher than in P. lilacinus
but comparable with the effects of G.
roseum. The relatively low volume of
spores produced by these fungi in cul-
tures when used in the tuber dip and soil
mix treatments may account for its low
effectiveness.
On the other hand, water lily alone
.showed some control of the nematode. It
reduced the cyst nematode count by
16.8% as compared with the check. This
effect was not significantly different from
those of A. cladodes and G. roseum in
tuber dip treatment. That extracts of
water lily may have some gematicidal ef-
fects supports the result of our current
study (Guzman, 1983, personal commu-
nication). This finding could add more
valnh to the hinlnoical cnntrl hv P lila-


cinus, G. roseum and A. cladodes as they
are easily grown in water lily substrate.
By applying both the fungus and the
water lily into the soil a higher control
effectiveness against the. nematode may
be obtained.
Effects on the yield of potato. The dif-
ferent fungal treatments that showed
effectiveness against G. rostochiensis have
resulted in significant increase in yield of
potato (Table 2). These effects, however,
varied with the different methods of
applying the fungi to control the nema-
tode. Higher yield was obtained when the
Eungi were applied both as tuber dip and
soil mix with water lily as the substrate.
The yield increases ranged from 32.4 to
36.5% which is comparable to those ob-
:ained with isazofos (Miral 10G) treat-
ment (36.3%), but not as high as those
with phenamiphos (Nemacur 10G) treat-
ment (59.4%). The tuber dip treatment
with P. lilacinus and G. roseum gave rela-
tively higher yield increase than the soil
nix though not significant. The A. clado-
les tuber dip treatment gave 20.3%
yield increase whereas the water lily alone
gave the lowest yield increase of 12.1%,
>ut this is significantly higher than the
yield of the non-treated check. The two
P. lilacinus isolates gave comparable yield
increases regardless of the method of ap-
plication. Likewise, the yield increases in
G. roseum treatment in tuber dip, soil
mix, and the combination of both were
not significantly differefit and were com-
parable with similar treatments with
P. lilacinus and A. cladodes.
The data on Table 3 showed greater
yield increases of first and second class
potato due to the control of the cyst
nematode by the fungal treatments. How-
ever, none has surpassed the yield in-
crease of 116.45% first class and 77.50%
second class obtained from phenamiphos
treatment. On the other hand, the yield
increases were comparable with those of
isazofos treatment. For instance, the first


31









32


lippine Phytopatholi


d nematicide treatments on yield of potato


Yield per replication (kg/4 m2)
IlI IV Mean' Increase


9.8 9.0 94. bc 27.0
9.4 9.6 9.1 c 22.9
9.2 9.7 10.1 b 36.6

8.6 7.7 9.3 bc 26.0
8.1 9.5 8.9 cd 20.3
10.0 8.3 9.9 be 33.8

8.2 11.6 9.5 be 283
9.3 8.5 9.1 c 22.9
10.4 9.2 9.8 bc 32.4

8.0 8.4 8.9 cd 20.3
8.0 9.4 8.3 d 12.1

12.2 12.8 11.8 a 59.4
10.3 10.8 10.3 b 39.2
7.2 8.4 7.4 e

n a column are not significantly different al


increase as compared to 25.97% in Peru
isolate, while the second class yield foi
the Philippine isolate was 40.98% as com
pared to 64.66% for the Peru isolate
Both isolates gave comparable increases in
the first and the second class yield in the
combined tuber dip and soil-mix treat-
ment. The first class yield in G. roseum
treatment was much higher (61.90%)
than the Philippine and Peru isolates of
P. lilacinus (44.58%), but the second class
yield increase (45.94%) was comparable
to the Philippine isolate (44.16%) using
the tuber dip treatment. In the soil mix
treatment with G. roseum, first class yield
increase of 42.85% was comparable with
that of P. lilaGinus Phil. isolate (42.86%)
but higher than that of Peru isolate
(25.97%). Its second class yield was lower
than in both P. lilacinus isolates. The first
class yield increase in G. roSeum com-


Table 2. Comparison of effects of fungal an
cv. Isola.


TREATMENT I

P. lilacinus
Peru Isolate
Tuber dip 8.3 10.4
Soil mix 9.0 8.5
Combination 10.8 10.9
Phil. Isolate
Tuber dip 9.2 11.7
Soil mix 8.6 9.6
Combination 10.7 10.5
G. roseum
Tuber dip 9.0 9.4
Soil mix 8.8 9.8
Combination 11.1 8.4
A. cladodes
Tuber dip 8.7 10.8
Water lily (Soil mix) 7.4 8.4
Nematicides
Phenamiphos 10 G 11.9 10.4
Isozofos 10G 9.2 11.0
Check 7.0 6.9

'Means followed by the same letter ih
5% DMRT.

class yield increase in isazotos treatment
was 59.74% which was comparable with
that of G. roseum tuber dip treatment
(61.90%). Likewise, the second class yield
increase of 69.61% in isazofos treatment
was also comparable with that of the
second class yield in P. lilacinus (Peru
isolate) in the soil mix (64.66%) and com-
bined treatments (69.90%) and also with
the Philippine isolate combined treatment
(62.54%).
With the tuber dip treatment, the Peru
isolate of P. lilacinus gave a higher per-
centage yield increase in first class potato
(44.58%) than the Philippine isolate
(16.40%). On the other hand, the Philip-
pine isolate gave a second class yield of
45.95% as compared to 36.04% for the
Peru isolate.
With the soil-mix treatment, the Philip-
nine isolate cave 42.86% first class vield











Jan. & June 1983


Evaluation of Three Nematophagous Fungi


Table 3. The marketable tuber yield of potato var. Isola from the fungal and nematicide
treatments1



Treatment and Yield per replication (Kg/4 m2)
Class Yield
I I HI IV Mean Increase

P. lilacinus


3.40 3.0 2.75 3.35
4.25 3.6 4.85 3.85

3.40 2.90 3.75 2.91
4.25 5.30 3.05 5.66

4.65 2.30 3.25 3.36
4.00 4.55 5.00 4.78


4.15 2.45 2.15 2.92
3.95 4.35 4.15 4.13

3.35 1.75 2.55 3.40
5.25 4.85 3.75 3.99

3.30 3.00 3.00 3.22
335 5.55 5.00 4.60


4.70 3.55 3.65 3.75
530 4.55 3.90 4.08

3.25 2.95 3.65 3.30
4.30 4.55 3.90 3.91

2.65 2.30 3.75 3.39
3.85 4.90 3.75 4.06


Peru Isolate
Tuber dip
1st
2nd
Soil mix
1st
2nd
Combination
1st
2nd
Phil. Isolate
Tuber dip
1st
2nd
Soil mix
1st
2nd
Combination
Ist
2nd
G. rosewn
Tuber dip
1st
2nd
Soil mix
1st
2nd
Combination
1st
2nd
A. cladodes
Tuber dip
1st
2nd
Water lily (Soil mix)
1st
2nd
Nematicides
Penamiphos
1st
2nd
Isazofos
Ist
2nd
Check


1The third class was excluded as the tubers were too small and not marketable


bined tuber dip and soil mix treatment
was more or less comparable to those of
both P. lilacinus isolates but the second
class yield was lower.


Water lily alone gave comparatively
lower yield increase than the fungal and
nematicide treatments, but it increased
first and second class tuber yield by


3.25 4.00 2.25 2.70 3.05
3.30 3.20 4.15 3.50 3.52

2.95 3.50 1.45 3.85 2.83
2.30 2.75 4.60 3.75 3.20


5.55 5.20 5.30 4.10 5.04
4.85 3.25 5.20 6.70 5.00

3.50 4.05 3.30 3.90 3.69
4.35 4.85 4.55 4.85 4.8

2.50 2.70 1.00 3.05 2.31
2.90 3.60 1.50 3.35 2.85












18.3% and 13.u,/o, respectively, in te suspension or m me sou as wen as
The overall results of the experiment the time and number of applications into
showed that biological control of G. ros- the soil are fully investigated. Will they be
tochiensis on potato using P. lilacinus, more useful and effective if combined
G. roseum and A. cladodes could result in with each other and with less expensive
significant increase in potato yield (Fig. nematicides or with other methods of
1). However, the potential effectiveness control against the nematode? These need
of these fungi against the nematode can- to be answered to maximize their effect-
not be fully utilized until their optimum iveness.
requirements for substrates, spore density




i


Fig. 1. Effects of G. roseum (1) P. lila
of potato cv. Isola as compared m
cides Miral 10G (5) and Nemacur 1


Lus" (2) and A. cladodes, (4) on yield
h the untreated check (3) and the nemati-
G (6).


34









on of Three Nematophagou~


LITERATURE CITED

DAVIDE, R.G. and R.A. ZORILLA. 1983.
Evaluation of a fungus Paecilomyces
lilacinus for the biological control of
potato cyst nematode Globodera ros-
tochiensis as compared with some
nematicides. Phil. Agric. 66(4): 397-
404.

JATALA, P., R. KATENBACK and BO-
CANGEL. 1979. Biological control
of Meloidogyne incognita acrita and
Globodera pallida on potatoes. J. Ne-
matol. 11:303 (Abstr.).

REYES, T.T. and R.G. DAVIDE. 1975.
Fungi for biological control of plant
parasitic nematodes. Phil. Phytopathol
Soc. Bull. 3.

VERZOLA, E.A. and T.A. KHAYAD.
1982. Survey of cyst nematodes on
seed potato growing areas in Benguet.
Phil. Phytopathol. 18. 3 (Abstr.).

VILLANUEVA, L.M. 1983. Studies on
the fungi Paecilomyces lilacinus
(Thom.) Samson and Arthrobotrys
cladodes Drechs. for the control of
nematodes, Globodera rostochiensis
Woll. and Meloidogyne incognita Chit-
wood. Ph.D. Thesis, p. 158. University
of the Philippines at Los Bafios.

ZORILLA, R.A. and R.G. DAVIDE. 1983.
Host range, development and survival
of potato cyst nematode Globodera
rostochiensis on potato in the Philip-
pines. Phil. Agric. 66(4) : 439-447.


35









Philinn Phvtnnmth


6-43


IL, NEEM OIL, AND MIXTURES
ETTIX VIRESCENS AND ON
US TRANSMISSION

JXENA, AND K.C. LING

ant Pathology, International Rice Research
ist, Int'l Centre of Insect Physiology and
ate Entomologist, IRRI; and Plant Patholo-
ilippines.

T

ires were found to be effective in reducing
tens (Distant) and its tramission of the rice
insect survival and RTV transmission to
0% concentration, or mixtures at 1:1, 1:2,
mncentration were significantly less than in
ro custard-apple oil, and custard-apple oil
ntrations were distinctly superior to other
in, the lower was the insect survival and
ve and transmit RTV to oil-sprayed plants
mnts, the insect survived for more than 20
tus, custard-apple oil and neem oil possess
vision by the vector. The antifeedant and
1 neem oil and mixtures are of additional


cost of synthetic insecticides and the
growing awareness of ecological hazards
associated with their large-scale use have
evoked a worldwide interest in pest con-
trol agents of plant origin.
The potential of seed oils of custard-
apple, neem, and chinaberry (Melia azeda-
rach L.) for use against several common
rice insect pests has been demonstrated at
the International Rice Research Institute
(IRRI) (Saxena et al. 1981 a, b; Saxena
et al. 1984). Also, the incidence of the
ragged stunt virus disease transmitted by
the brown planthopper,Nilaparvata lugens
(Stal), was significantly reduced in rice
fields sprayed with a 12% crude neem oil
emulsion (Saxena et al. 1981a). Custard-
apple oil is reportedly used by farmers in
Vietnam for protecting rice crop from
leafhoppers and planthoppers (Brady et
al. 1978). A synergistic insecticidal acti-
vity comparable to DDT was reported in
combinations of custard-apple and neem


EFFECT OF CUSTARD-APPLE I
ON SURVIVAL OF NEPHO1
RICE TUNGRO VII

V. MARIAPPAN, R.C. S

Respectively, Postdoctoral Fellow in I
Institute (IRRI); Principal Research Scier
Ecology (ICIPE), Nariobi, Kenya, and Asso,
gist (Deceased), IRRI, Los Baflos, Laguna, F

ABSTRA

Custard-apple oil, neem oil, and mix
the survival of the green leafhopper N. vire
tungro virus (RTV). Mean percentages o
plants sprayed with oils at 5, 10, 20, 30, or
or 1:4 proportions (V/V) at 5, 10, or 20%
control plants. Treatments involving > 2
plus neem oil mixtures at all the three con
treatments. The higher the oil concentrate
RTV transmission. The insect failed to sur
3 days after oil application. On control p
days and transmitted RTV up to 5 days. 1
potential for suppression of RTV transrr
insecticidal activities in custard-apple oil a
value in the control of the pest.

Custard-apple (Annona squamosa L.)
and neem (Azadirachta indica A. Juss)
plants are widespread in many rice-growing
countries of South and Southeast Asia.
Although there is no commercial cultiva-
tion of these plants, they are grown over
fairly large areas in some countries. For
example, custard-apple plants occupy
nearly 45,000 ha of land in India and are
a source of considerable quantities of
nonedible oil (S.D. Thirumala Rao, per-
sonal communication). Likewise, there
are about 14 million neem trees in India
and the annual neem oil production
averages 83,000 tons (Ketkar 1976).
While antifeedant and insecticidal proper-
ties of these oils are well known in folk-
lore and in traditional agriculture, the
advent and acceptance of highly effective,
broad spectrum, synthetic insecticides
relegated them for use in the manufacture
of low quality soaps, detergents, lubri-
cants, paint thinners, etc. The increasing









stard-Apple Oil, Neem Oil, &


:ed extracts (Qadri et al. 1977). We,
therefore, tested the effect of custard-
pple oil, neem oil, and their mixtures on
he survival of the green leafhopper,
Tephotettix virescens (Distant), and on
:s transmission of rice tungro virus
RTV).

MATERIALS AND METHODS

Crude neem oil expelled from decorti-
ated seeds (1981 crop) was obtained
rom Mr. C.M. Ketkar, Technical Advisor
o the Neem Manurial Project, Poona,
ndia. Custard-apple oil was obtained by
nethanolic extraction of decorticated
eeds obtained locally. Oils were emulsi-
led in water with 0.1-1% 'Teepol' liquid
etergent individually and as their res-
,ective 1:1, 1:2, 1:4 (V/V) mixtures and
ested at different concentrations. Ten-
.ay-old Taichung Native 1 (TN1) rice
eedlings were sprayed separately with
he various oil emulsions at 0.5 ml/40
eedlings using a spray atomizer (Pierce
chemicall Co., P.O. Box 117, Rockford,
11. 61105, USA) 3 hours before exposure
o the vector. Control seedlings were
prayed with the detergent solution.
treated seedlings were placed individually
n glass test tubes (15 x 1.5 cm) and
arranged by treatments in racks. Newly-
merged N. virescens adults that had been
lowed a 4-day acquisition access feeding
in source plants (Ling 1972) were used as
he vector. For inoculation access feeding,
ne viruliferous adult was released into
ach test tube which was then covered
vith a polyvinyl cap. After 24 hours, the
eedlings were removed and transplanted
n pots. Freshly treated seedlings were
substituted in test tubes containing sur-
riving virulifeous insects. Successive ino-
:ulation access feeding of the survivors on
treated plants continued until the death
Af all the viruliferous insects. Disease
symptoms in inoculated seedlings were
observed starting 12 days after inocula-
tion.


RESULTS

Custard-apple oil, neem oil, an
fixtures reduced insect survival an


I their


ceding, nearly all insects survived in the
control. Survival was significantly less on
11 oil-sprayed plants the higher the oil
concentration, the lower the insect sur-
ival (Tables 1 and 3; Fig. 1). Insect sur-
ival continued to remain high (80-100%)
ven after 2 to 3 days feeding on control
seedlings. On the other hand, only 2% of
he insects survived at 2 days after feed-
ig on seedlings treated with 30% custard-
pple oil; none survived at 50% concen-
ration. At 3 days after feeding, survival
,ecame negligible on seedlings treated
tith lower concentrations of custard-
pple oil (Tables 1 and 3). A similar trend
ias observed in the reduction of insect
survival in treatments involving neem oil.
:ustard-apple oil and neem oil mixtures
iere much more effective than individual
mil treatments and hardly any insects sur-
ived 2 to 3 day feeding periods on seed-
ings treated with oil mixtures (Table 3).
Transmission of RTV by the viruli-
erous insect to oil-sprayed rice seedlings
vas represented by the number of in-
ected seedlings. One day inoculation
access feeding infected 60-69% of the
controll seedlings (Tables 2 and 4). In-
ection of oil-sprayed seedlings was signi-
icantly less at all concentrations of
;ustard-apple oil and oil mixtures, how-
!ver, neem was effective only at > 10%
concentrationn (Fig. 2). After 2 days of
noculation access feeding, 35.5-56% of
he control seedlings were infected; signi-
icantly less infection occurred in all oil
treatments. Infection of seedlings treated
vith 20% custard-apple oil or with oil
fixtures was < 7%. After 3 days of
feeding, few insects survived and only a
ew plants were infected. After 4 days, no
eedlings were infected because no insects
survived on oil-sprayed seedlings. How-
ever, on the control seedlings, the viruli-


J/









Philippine Phytopathology


Table 1. Survival of Nephotettix viresce
seedlings sprayed with custard-i
1981-82.

Oil concn.
(%) day
CAO NO
5 25 b 58 b
10 28 b 37 c,
20 23 bc 42 c
30 17 bc 34 c,
50 2c 27 d
Ob 96 a
(control:
water + 0.1% liquid detergent

aWithin a day, in a column, mean
cantly different at the 5% level by DIM
replicate.
bControl treatment was common t

Table 2. Rice tungro virus (RTV) infecti
apple oil (CAO) and neem oil (
insects. IRRI, 1981-82.

Oil concn.
(%) ____
CAO
5 25 b
10 19 be
20 19 bc
30 20 be
50 11 c
0b
(control: water + 0.1% liquid detergent)

aWithin a day, in a column, mean=
cantly different at 5% level by DMRT; a
cate.
bControl treatment was common tc


after 1, 2, and 3 days exposure on TN1 rii
ple oil (CAO) and neem oil (NO). IRRI.

Survival (%) N. virescensa
2 days 3 days 3 days
CAO NO CAO N
5b 24b Ob 7
6b 17 bc lb 6
6b 8bc lb 0
2b 3c Ob 0
Ob 3c Ob 0
87 a 80



followed by a common letter are not signif
T; average of 5 replications, 440 insects pt

)oth oils.

i in TN1 rice seedlings sprayed with custard
3) after T and 2 days exposure to viruliferou

XTV infection (%) of TN1 seedlings
day 2 days
NO CAO NO
27b 7b 14b
16 bc 4b 1 b
21 bc 2b 10b
14c llb Sb
12c Ob 10b
Sa 36 a


followed by a common letter are not signifi
rage of 5 replications, 440 insects per repli

oth oils.


38








































cantly anterent at tne 370 level oy vMKI ; average or 3 replications, jzu insects per
replicate.

Table 4. Rice tungro virus (RTV) infection in TN1 rice seedlings sprayed wrh custard-
apple oil (CAO) and neem oil (NO) and their mixtures after 1, 2, and 3 days
exposure to viruliferous insects. IRRI, 1983.a

RTV infection (%) of TN1 seedlings
Treatment Oil concn.
(%) 1 day 2 days 3 days
CAO 5 38 d 16 de 2 d
CAO 10 34 de 12 de Od
CAO 20 23 fg 7 ef Od
NO 5 67 ab 40 b 15 b
NO 10 56 c 28 c 8 c
NO 20 58 bc 20 cd Od
CAO + NO (1:1) 5 25 ef 6 fg 0 d
CAO + NO (1:1) 10 21 fg Oi Od
CAO + NO(I:1) 20 11 i Oi Od
CAO + NO (1:2) 5 21 fg 7 ef 0 d
CAO + NO (1:2) 10 19 fg 3 gh 0 d
CAO + NO (1:2) 20 15 ghi 0 i 0 d
CAO + NO (1:4) 5 17 fgh 3 gh 0 d
CAO + NO (1:4) 10 14 ghi 3 ghi 0 d
CAO + NO (1:4) 20 11 hi 1 hi 0 d
Control (water +
1% liquid detergent) 0 69 a 56 a 36 a

aWithin a day, in a column, means followed by a common letter are not signifi-
cantly different at the 5% level by DMRT; average of 5 replications, 320 seedlings per
replicate at the commencement.


ter 1, 2, and 3 days exposure to TN1 rice
: oil (CAO) and neem oil (NO) and their


Insect Survival (%)

1 day 2 days 3 days
62 cd 25 cd 5 c
52 d 15 de Oc
19 efg 2fg 0c
82 b 50b 19 b
70 bc 34 bc 7 be
52 d 17 de Oc
29 e 7 ef 0 c
16 efg 1 fg Oc
7g 0g Oc
23 ef 3 fg 0 c
16 efg 4 fg 0 c
7 g 0g 0c
13 efg 0 g 0 c
10 fg 0 g 0c
9 g 0g 0c

100 a 100 a 97 a

1^,,,,J 1-. -, , -__ __~ 1A ^-- ---L -* -*^:r


iadle 3. aurvival o0r vepnoerIu virescens
seedlings sprayed with custard-ap
mixtures. IRRI, 1983a

Treatment Oil concn.

CAO 5
CAO 10
CAO 20
NO 5
NO 10
NO 20
CAO + NO (1:1) 5
CAO + NO (1:1) 10
CAO+NO(1:1) 20
CAO + NO (1:2) 5
CAO + NO (1:2) 10
CAO+NO(1:2) 20
CAO + NO (1:4) 5
CAO + NO (1:4) 10
CAO + NO (1:4) 20
Control (water +
1% liquid detergent) 0
a.-.. . .











Philippine Phytopathology


Insect Survivl 0/.1
80 cAsio-iswOt .l
.5%.
S10%
60 20%

40



0
S 3
: 2 3


1 2 3


Seedlngs infected 1%)
S---d-WP--Ro- A0-
60- 5%

40

20


50
40 *O C n O oi0nn
40 (CA) ') CA0 2I A1



2203 2 3 1 3
2 3 1 2 3 1 a 3


80 nor I

60

40



0
5 10 20


5 10 20
01 concentration (%)


Oay


- CAO
*wo0
.NO
-.CAO.NO(I 1)




5 '0 20


Fig. 1. Average survival of N. virescens
exposed at different lengths of
time on'TN1 rice seedlings treated
with emulsions of custard-apple
oil, Neem oil and their mixtures.
IRRI, 1982-1983.






ferous insects continued to survive for
more than 20 days and transmitted RTV
up to 5 days.
DISCUSSION

Most insect damage to plants results
from direct feeding or indirectly from
transmission of pathogens during feeding.
Antifeedants that retard or disrupt feed-


40 clO A CAO I
((I 0 ( 41



0 2 3 1I 2 3





20



Fig.2. Average RTV infection of TN
.-.CM*O,2I 4)



5 10 20 5 10 20 5 10 20
01 conocntrotion (%)

Fig. 2. Average RTV infection of TN1
rice seedlings treated with emul-
sions of custard-apple oil, Neem
oil and their mixtures when ex-
posed to viruliferous N. virescens.
IRRI, 1982-1983.







ing activities of insect pests or vectors by
rendering plants unattractive or unpalata-
ble, offer a novel approach in pest and
vector management.
A significant reduction in food intake
by N. lugens, the whitebacked plant-
hopper Sogatella furcifera (Horvath), and
N. virescens occurred on rice plants
sprayed with oil of neem, chinaberry, or


VoL 19









istard-Apple Oil, Neem Oil,


custard-apple (Sacena et al. 1981a; 1984). limonoids (Jacobson 1981; Kraus et al.
Among the three seed oils tested, the oil 1981; Morgan 1981). We hope that the
of custard-apple was the most effective use of custard-apple oil and neem oil mix-
against N. virescens, causing significantly tures will not be as prone to the develop-
high adult mortality at doses of > 20 pg/ ment of resistance by N. virescens as
insect (Saxena et al. 1984). Recently, the would be ordinary insecticides. The anti-
insecticide potential of the oil from feedant and insecticidal activities in cus-
edible fruits of a Nigerian Shrub, Dennet- tard-apple oil and neem oil mixtures are
tia tripetala G. Baker, belonging to the of additional value in the control of the
custard-apple family, has also been pest.
reported (Iwuala et al. 1981). We found Application of oils is generally recom-
that custard-apple oil, need oil, and their mended for protecting crop plants from
mixtures considerably reduced insect insect-transmitted virus diseases. Accord-
survival on treated plants and transmis- ing to Simons and Beasley (1977), sup-
sion ofRTV. pression of transmission of stylet-borne
viruses by mineral oils was due to the
Although N. virescens is still con- accumulation of oil on the anticlinal wall
trolled effectively with insecticides in the of leaves where mineral oils acted mainly
tropics (Heinrichs 1979), Nephotettix as interfering agents. Nonetheless, Simons
cincticeps Uhler, a closely related pest (1981) stressed the importance of using
species became resistant to organophos- oil formulations with naturally occurring
phates and carbamate insecticides in antifeeding substances derived from
Japan (Kojima et al. 1963; Iwata and plants. Neem oil and custard-apple oil, in
Hama 1971; Kiritani 1972; Asakawa and addition to their inherent repellent, anti-
KV7ann 1071 nrl i Tii. fT4..- T -


span of time. Only a few insecticides are
now effective against N. cincticeps since
it has developed cross-resistance. Also,
none of these insecticides have been
found to be safe for the pest's natural
enemies, making integrated control diffi-
;ult (Kiritani 1976). Extensive use of
insecticides may also lead to the develop-
nent of insecticide resistant N. virescens
n the tropics.
The likelihood of insect pest develop-
ng resistance against plant derivatives
:omprising an array of chemicals causing
diverse behavioral and physiological ef-
',nte ie mlifh 1pae than when ineprtiridrl


also reduce V. virescens transmission of
RTV by acting as interfering agents.
Unlike insecticides that kill both pests
and predators outright, neem oil and
custard-apple oil are relatively inactive
against natural enemies of leafhoppers
and planthoppers which subsist on pests
rather than on plants (Saxena et al. 1984).
The biodegradable nature of these oils
(Saxena et al. 1981b) also minimizes the
hazards of environmental pollution.
Effective control of crop pests and
vectors by the small-scale farmer in de-
veloping countries of Asia and Africa has
been limited because of the prohibitive


41









Philippine Phytopathology


neem can be grown by farmers in mar-
ginal areas of Asia and Africa with mini-
mal maintenance and their oils can be
extracted using simple devices. Although
these oils may not match synthetic insec-
ticides in efficacy, even the partial pest
control obtained by using them is better
than no control at all. Effectiveness
against pests, safety for the environment,
low cost, and availability of these oils em-
phasize that they should be considered
seriously for pest and vector control.

LITERATURE CITED

ASAKAWA, M. and H. KAZANO. 1976.
Resistance to carbamate insecticides in
the green rice leafhopper, Nephotettix
cincticeps Uhler. Rev. Plant Prot. Res.
9:101-123.

BRADY, N.C., G.S. KHUSH and E.A.
HEINRICHS. 1978. Visit of the
IRRI Team to the Socialist Republic
of Vietnam, April 30 May 9, 1978.
International Rice Research Institute,
Los Bafios, Laguna, Philippines. 49 pp.

HEINRICHS, E.A. 1979. Control of the
leafhopper and planthopper vectors of
rice viruses. pp. 529-560. In K. Mara-
morosch and K.F. Harris (eds.) Leaf-
hopper Vectors and Plant Disease
Agents. Academic Press Inc., N.Y. 654
pp.

HUE-LIEN KAO, MING-YIE LIU and
CHIH-NING SUN. 1982. Nephotettix
cincticeps (Homoptera: Cicadellidae)
resistance to several insecticides in
Taiwan. J. Econ. Ent. 75:495-496.

IRVINE, F.R. 1955. West African Insec-
ticides. Colon. Plant Anim. Prod. 5:
34-38.

IWATA, T. and H. HAMA. 1971. Green
rice leafhopper, Nephotettix cincticeps
Uhler. resistant to carbamate insecti-


cides. Botyu-Kagaku 36:174-179.

IWUALA, M.O.E., I.U.W. OSISIOGU and
E.O.P. AGBAKWURU. 1981. Dennitia
oil a potential new insecticide: tests
with adults and nymphs ofPeriplaneta
americana and Zonocerus variegatus.
J. Econ. Ent. 74: 249-252.
JACOBSON, M. 1981. Neem research in
the U.S. Department of Agriculture:
Chemical, biological and cultural as-
pects. pp. 33-42. In H. Schmutterer,
K.R.S. Ascher, and H. Rembold (eds.)


42









Jan. & June 1983 Effect


indica A. Juss). Proc. 1st Int. Neem parvata lugens. pp. 171-188. In H.
Conf., Rottach-Egern 1980. 297 pp. Schmutterer, K.R.S. Ascher, and H.
Rembold (eds.) Natural Pestipides
LING, K.C. 1972. Rice virus diseases. In- from the Neem Tree (Azadirachta in-
ternational Rice Research Institute, dica A. Juss). Proc. 1st Int. Neem
Los Bafios, Laguna, Philippines. 142 pp. Conf., Rottach-Egern 1980. 297 pp.

LITSINGER, J.A., E.C. PRICE and R.T. P.B. EPINO, TU CHENG
HERRERA. 1980. Small farmer pest WEN and B.C. PUMA. 1984. Neem,
control practices for rainfed rice, corn chinaberry, and custard-apple: anti-
and grain legumes in three Philippine feedant and insecticidal effects of seed
provinces. Philipp. Entomol. 4:65-86. oils on leafhopper and planthopper
pests of rice. In Proc. 2nd Int. Neem
Conf., Rauisch-Holzhausen Castle
MORGAN, E.D. 1981. Strategy in the 1983 (in press).
isolation of insect control substances
from plants. pp. 43-52. In H. Schmut- G.P. WALDBAUER, N.J.
terer, K.R.S. Ascher, and H. Rembold LIQUIDO and B.C. PUMA. 1981b. Ef-
(eds.) Natural Pesticides from the fects of neem seed oil on the rice leaf-
Neem Tree (Azadirachta indica A. folder, Cnaphalocrocis medinalis. pp.
Juss). Proc. 1st Int. Neem Conf., Rot- 189-203. Ibid.
tach-Egern 1980. 297 pp.
SIMONS, J.N. 1981. Innovative methods
NAIDU, N.B., M.B. NAIDU, Z.H. OSMA- of control for insect-transmitted plant
NI and S.A. SALETORE. 1953.Studies viral diseases. pp. 169-178. In J.K.
on Annona squamosa (Sitaphal) seed. Mckelvy, Jr., B.F. Elridge and K. Mara-
Part II. The insecticidal fatty oil. morosch (eds.) Vectors of Disease
Indian Chem. Soc. J. Indus. News Ed. Agents, Interaction with Plants, Ani-
16:180-184. mals, and Man. Praeger Publishers,
New York 10175, U.S.A.
QADRI, S.S., H. RAO and B. BRAHMA-
and C.A. BEASLEY. 1977.
NAND. 1977. Effect of combining Visualization of oil on leaf surfaces -
some indigenous plant seed extracts
someont I...hi l ... Pit a technique. J. Econ. Entomol. 70:


11:21-23.

SAXENA, R.C., N.J. LIQUID and H.D.
JUSTO, Jr. 1981a. Neem seed oil, a
potential antifeedant for the control
of the rice brown planthopper, Nila-


Acknowl

The senior author is indebted to IR]
in Plant Pathology and to the Tamil Nad
station at IRRI. Dr. D.P. Lapis, associate p
Philippines, Los Bafios critically review
Department of Statistics, IRRI, analyzed


WATT, J.M. and M.G. BREYER-BRAND-
WIJK. 1962. The Medicinal and Poi-
sonous Plants of Southern and Eastern
Africa. Ed. 2, Edinburgh & London.
1457 pp.



rment

for the award of a post-doctoral fellowship
Agricultural University, India, for his depu-
essor of plant pathology, University of the
the manuscript. Ms. Grace Lasat-Reyes,
data.









Philipp. PhytopathoL 19: 44-49


ASSESSMENT OF LOSSES CAUSED BY TMV ORDINARY
STRAIN ON FLUE-CURED TOBACCO

LUZVEMINDA A. REVELLAME and VIRGILIO C. RUGUIAN

Science Research Specialist and Research Assistant, respectively, Philippine
Tobacco Research and Training Center, MMSU, Batac, Ilocos Norte, Philippines.
The assistance of Mr. Romeo Carasi and Mr. Solnacer Sugui in the preparation and
maintenance of the experimental field and gathering data is gratefully acknowledged.

ABSTRACT

The damage caused by TMV (orindary strain) on the growth, agronomic per-
formance and physical quality of the leaves of four flue-cured tobacco cultivars namely
*Balikbayan, MRS-3, NCBY, and Coker 254 was evaluated.
Time of inoCulating tobacco with the virus had significant influence on plant
height, leaf area, cured yield and crop value but not on the number of harvested leaves.
When inoculated at 15, 30, and 45 DAT, the respective percent losses compared to the
healthy plants were the following: average leaf area: 16.44, 32.21, and 22.82; cured
yield: 76.6, 36.8, and 34.4; grade index: 73.4, 23.1, and 23; and crop value: 92.4
46.0 and 49. The response of all four cultivars to infection followed similar trend. The
damage caused by the disease was greatest in plants infected early and decreased as
infection was delayed.
Reduction in yield and crop value was attributed to the deleterious effect of the
virus on plant growth, leaf weight, and physical quality of cured leaves.


One of the most serious and widely
distributed disease of tobacco is mosaic.
It is found in any place where the crop
is grown and causes considerable eco-
nomic losses to growers. In the United
States alone, annual losses from the
disease averaged to more than a million
dollar from 1960-65 period (Gooding,
1969). In 1975, Lucas estimated loss of
about 1% of the crop per year, and in
1976, 78 M $ (Collins, et al. 1977).

Information on the losses paused by a
certain disease to a crop is valuable in
establishing research priority and the
campaign for its control. In the Philip-
pines, mosaic was first reported in 1921
(Lee, 1921) and has always been regarded
as a highly destructive (PCARR, 1979)
disease of tobacco. However, report on the
quantity and quality of damage caused by
this disease under local condition is still
lacking. This study has the following ob-
jectives: 1) to assess the quantity and


quality of damage by TMV on flue-cured
tobacco at different times of inoculation
and 2) to determine the response of some
highly promising cultivars to the patho-
gen.

MATERIALS AND METHODS

Inoculum preparation and inoculation
The virus (TMV-ordinary strain) was
collected from infected tobacco in an ex-
perimental field of PTRTC and isolated
by the single lesion isolation technique
(Noordam, 1973). It was multiplied in
flue-cured tobacco cv Balikbayan in a
screenhouse.
The inoculum was a distilled water-
diluted sap (1:100 weight of tissue/
volume liquid) from the young laves of
infected plants. Celite powder was added
to make 1% of the inoculum.
Inoculation was made by gently rub-
bing the three youngest well expanded
leaves with cotton pads saturated with
inoculum.









Assessment of Losses


S Field Layout
The experiment was conducted in a
semi-upland field in Batac, Ilocos Norte.
A split-plot design in RCB with four repli-
cation was used. The different times of
inoculation, 15, 30, and 45 days after
transplanting (DAT) and uninoculated
control were the main plots and the culti-
vars, Balikbayan, MRS-3, Coker 254 and
NCBY, the sub-plots.
Forty day-old seedlings of approxi-
mately the same size were transplanted at
* a distance of 80 cm and 50 cm between
rows and hills, respectively. The main
plots were 1.0 m apart and the blocks,
1.5 m. Each sub-plot contained 5 rows of
plants with 12 hills per row. A single row
of TMV-resistant plant (cv Vamorr 50)
was planted around each uninoculated
plot (control) to minimize the spread of
the disease.
Fertilizers, 6-9-15 (30 g/hill) and 21-0-0
(10g/hill) were broadcasted (by hand) at
transplanting and dibbled 30 days after,
respectively. The field was irrigated four
times, twice by hill to hill method and
twice by furrow. Off-barring and hilling-
up were used to control weeds. The num-
ber of harvested leaves was counted per
priming and the average per plant taken
after all primings were finished. Plant
height was measured from the base of the
plant up to the last node below the in-
florescence at button stage (when 3-4 flo-
rets are opened in an inflorescence). The
average leaf area, cured yield (total har-
vested cured leaves), leaf grade index, and
crop value were computed using the fol-
lowing formulas:
leaf area = L x W x 0.6345 (constant)
where: L length of leaf
W = width of the broadest
partition of the leaf


Average leaf area -
Average leaf area of 10 leaves at priming
1 + ... + at last priming


Cured yield (t/ha) =
Wt. of leaves from all primings/plt (kg)
x Plant population/ha
100 kg/ton


Percent Grade A
Leaf grade index = 100 x Nu-
merical value of A
Percent Grade R

x Numerical value of R

where:
Percent Grade A =
Wt. of A/plot from all primings x 100
Total wt of all primings/plot
after classification

The same formula was used for the
other grades.
Numerical value per grade:


Grade


Numerical value
7
6
5


Crop value/ha =
Total wt of A (kg) from all
primings/plot x
Number of sample plt/plot
x Price of A/kg
x Plant population/ha +...

+ Total t of R (kg) from all
primings/plot

Number of sample pit/plot

x Price of R/kg x Plant population/ha


Number of primings x Price of R/kg


Jan. & June 1983








Philippine Phytopathology


KESULIS ANUJ UOILUUMUIN

In assessing the effect of TMV on
growth and performance of tobacco,
four flue-cured cultivars were artificially
inoculated at varying 'ages after trans-
planting. Three of these, Balikbayan,
NCBY, and Coker 254 are all susceptible
to TMV-ordinary strain (Luna, et al,
1981) and one, MRS-3, resistant (Chaplin
et al., 1969).

Symptoms
All cultivars showed pale, chlorotic
local lesions four days after inoculation
and was followed a day or two by vein
clearing of the youngest leaf. This indi-
cated that all cultivars were systemically
invaded by the pathogen. The typical
green mottling, blistering, and mosaic
were observed in all leaves succeeding
the inoculated ones. In some instances,
extensive necrosis of tissues or mosaic
burn was observed in the lower inocu-
lated and uninoculated leaves. At the ad-
vanced stage of infection, the leaves pro-
duced by the diseased plants particularly
those infected early were misshapen,
small, thick, and brittle with numerous
minute necrotic spots all over. Curling
down of lamina edge was common.
Based on symptomatology, it ap-
peared that all varieties, including MRS-3
were susceptible to TMV. The resistance
genes of MRS-3 was derived from Nico-
tiana glutinosa L. (Chaplin et al., 1969)
which is characterized by necrotic local
lesion without systemic invasion of ino-
culated plants. Thus, the observed syste-
mic infection of the test plants indicated
that the MRS-3 cv used in the experiment
was possibly not genetically similar to the
original cultivar.
This contention was further supported
by observation in the experimental areas
of the PTRTC where natural infection by
TMV was prevalent in plots planted to
MRS-3. Speculation on the probable


cuase or causes or tnis apparent change or
resistance in MRS-3 is beyond the scope
of this paper.
Time of infection vs tobacco growth and
performance
Table 1 shows that the time of infec-
tion by TMV on tobacco had significant
influence on height, average leaf area,
cured yield, grade index, and crop value
but none on number of harvested leaves.
All infected plants were shorter (102.7-
134.4 cm) than the healthy ones (173.9
cm) and their heights were comparable to
each other. The leaf area progressively in-
creased with increasing interval between
transplanting and infection. The largest
mean leaf area was observed from the
uninoculated plants (875.08 sq cm) and
the smallest (274.47 sq cm) from plants
inoculated 15 DAT. These findings con-
form with those of Danko (1979) and
Diallo and Mulchi (1981) who demons-
trated that the growth reduction on
tobacco resulting from TMV-infection is
directly related to the length of time the
virus stayed in the plants. It was greater
when plants are infected young and be-
came lesser as infection was delayed.
The cell division, differentiation, and
formation of leafprimordia were seeming-
ly not significantly inhibited by virus in-
fection as shown by the similar number
of harvested leaves in infected and healthy
plants. It did, however, affected the en-
suing growth and expansion of the leaf.
Specifically, this phenomenon was attri-
buted by Lucas (1975) to the reduction
of activity of marginal meristemsin syste-
mically infected tobacco leaves. Since the
number of systemically infected leaves
decreased as inoculum time was delayed,
it explains the observed progressive in-
crease in average leaf area.
The results further indicated that in-
fection by the virus may have significant-
ly inhibited cellular processes related to
apical growth and development. Accord-
ing to Matthews (1970) this common


40






























MRS-3 145.50 18.6 519.69 1.31 4.21 10794.44
NCBY 138.75 18.1 552.22 1.23 3.90 9770.31
Coker 254 140.40 18.2 576.25 1.29 4.06 10758.12
45 Balikbayan 117.33 16.2 712.31 1.28 4.01 10083.75
MRS-3 153.68 17.1 758.46 1.43 3.96 10292.81
NCBY 136.70 18.2 588.58 1.34 4.04 9875.00
Coker 254 145.70 17.8 632.73 1.24 4.03 8078.12
Uninoculated
Balikbayan 163.43 15.5 937.21 1.93 5.24 18342.56
MRS-3 188.15 18.3 894.54 2.11 5.38 20398.44
NCBY 165.70 17.2 828.84 2.09 5.27 19980.00
Coker 254 178.18 18.9 839.74 1.90 5.16 17870.62
Significance (F-test)
Time of inoculation ** ns ** ** ** **
Cultivars ** ** ** ns ns ns
Interaction ns ns ns ns ns ns
% CV (a) 13.3 18.20 16.00 21.0 18.0 24.00
(b) 10.4 8.6 11.6 13.7 11.0 18.00
Means for inoculation time
15 102.7b 16.81 275.47d 0.47c 1.39c 1429.81c
30 138.3b 17.7 589.65c 1.27b 4.03b 10184.47b
45 138.4b 17.3 673.02b 1.32b 4.01b 9582.42b
Uninoculated 173.9a 17.4 875.08a 2.01a 5.26a 19147.91a
Means for cultivar
Balikbayan 127.64b 15.9b 662.48a 1.23 3.62 9785.00
MRS-3 148.07a 17.8a 615.07a 1.33 3.72 10699.75
NCBY 135.82a 17.7a 555.50b 1.28 3.66 10301.65
Coker 254 141.02a 18.0a 580.18a 1.23 3.68 9558.12

'Means followed by a common letter are not statistically significant at 5% level by
DMRT.

observation among plants infected with ble yield (1.27 and 1.32 t/ha) which was
viruses may be due to alterations in the lower than the healthy (2.01 t/ha) but
synthesis, translocation, and effectiveness higher than plants inoculated at 15 DAT.
of various growth stimulants like auxins, The disease also had unfavorable ef-
cytokinins, and gibberelins. fects on the physical characteristics of
Consequent to the reduction in leaf cured leaves. These appeared dark or
area, the cured leaf yield was also reduced, greenish with scattered necrotic flecks,
Lowest yield (0.46 t/ha) was obtained were thick, brittle and easily shattered.
from plants inoculated 15 DAT. Those Ordering for one hour at dawn did not
-____-l-A A --A AC T A' 1---1 +1,-nn n 1--ra- T- A ---- rt -4a


Assessment of Loues


47


ordinary strain on plant height, area and
rield, grade index and crop value on flue-
;2.

Average
Leaf Cured Crop
Area Yield Grade Value
(sq cm) (t/ha) Index (P)

Means for Individual Treatments
289.75 0.44 132 1299.06
287.61 0.47 1.31 1313.31
252.35 0.48 1.46 1581.25
271.99 0.47 1.48 1525.62


Table 1. Time of infections effect of TM
number of harvested leaves, cure
cured tobacco. PTRTC-Batac. 198

Inocu- Harv4
lation Plant ablb
Time Cultivar Height Leav<
(DAT) (cm) (No


15 Balikbayan 101.25 15.1
MRS-3 107.50 17.2
NCBY 102.15 17.1
Coker 254 99.18 17.2








Philippine Phytopathology


abnormalities was also in direct propor-
tion with length of infection of the plant.
The chlorotic areas of infected tobacco
leaves are thinner than the green areas
because of the reduction in palisade cell
length and smaller intercellular spaces
(Lucas, 1975). This morphohistological
abnormality may account for the necrotic
spots and the brittleness of infected
leaves. On the other hand, the dark color
maybe related to the biochemical changes
due to viral infection like reduction in
nicotine, starch, and reducing sugars but
greatly increased total N-content of the
leaf.
The locally existing grading system in
tobacco is more dependent on the phy-
sical characteristics of cured leaves parti-
cularly color and leaf length. Thus, the
grade index and subsequently, crop value
were also reduced in similar manner as
yield (Table 1). Highest grade index (5.26)
and crop value (P19,147.00) were ob-
tained from uninoculated plants and the
lowest grade index of 1.39 and crop value
of P1,429.00 were from plants infected
15 DAT. Those infected 30 and 45 DAT
had similar grade index (4.01-4.03) and
crop value (P9,582.40 P10,184.45).

Response of cultivars
There was no variety x inoculation
time interaction. Table 1 shows that plant
height, number and average leaf area of
harvested leaves, yield, grade index, and
crop value were all reduced with similar
trend regardless of the variety. These
findings are in agreement with a related
study of Gwynn (1977) involving some
TMV-resistant (local lesion and symptom-
less) and susceptible test cultivars of flue-
cured type where no significant inter-
actions between entries and disease condi-
tion was detected in two years of experi-
mentation.
Among the varieties, significant dif-
ferences were obtained only for plant
height, and the number and average area


of harvested leaves. Balikbayan was the
shortest (127.6 cm) had the least number
(15) but the biggest leaves (662.48 sq cm).
MRS-3, Coker 254 and NCBY had
similar height (148.7, 141.02 and 135.82
cm, respectively) and number of leaves
(18). The first two had comparable leaf
area with Balikbayan (615.07 and 580.18
sq cm). NCBY had the smallest leaf
(555.50 sq cm).

Infection time vs losses in leaf area, grade
index and crop value
When compared to healthy plants,
varying percent losses in growth and per-
formance parameters were obtained from
different times of inoculation. Percent
losses in leaf area, cured yield, grade in-
dex, and crop value were highest in plants
infected earliest (15 DAT) and become
lesser as inoculation was delayed to 30
and 45 DAT (Table 2). Furthermore, al-
though the percent losses in leaf area at
15 DAT inoculation was only 68.4% the
resulting losses in yield (76.6%, grade in-
dex (73.43%), and crop value (92.5%)
were very high. It may be possible that
reduction in yield was not caused solely
by the reduced leaf area but also reduced
weight per unit leaf area.
The effect on grade index and crop
value might have been compounded since
these two measures are both functions of
yield (weight) and physical characteristics
of cured tobacco. As cited by Lqcas
(1975), Chaplin (1964) found that with
30% reduction in tobacco yield from
TMV infection, the crop value is reduced
by 50%.


Vol. 19









Assessment of Losses


Table 2. Effect of time of inoculation wil
average leaf area, cured yield,
tobacco. PTRTC, Batac, 1982.

Inoculation Average leaf Cm
Time (DAT)1 area (sq cm)2 (

15 68.44a 71
30 32.21b 31
45 28.82b 3,


1DAT = days after transplanting.
2Means followed by a common lette
DMRT.



LITERATURE CITED

CHAPLIN, J.F., T.J. MANN, D.F. MAT-
ZINGER and J.L. APPLE. 1969. Regis-
tration of MRS-1, MRS-2, MRS-3 and
MRS-4 tobacco germplasm. Crop
Science 9:681.

COLLINS, W.K., S.S. HAWKS, JR., F.W.
CONGLETION, T.E. REAGAN, F.A.
TODD, R. WATKINS and C.R. PUGH.
1976. 1977 Tobacco Information.
Misc. Extension Publication AG-46.

DANKO, J. 1979. TMV and PVY in-
fection during various stages of tobac-
co growth and their influence on har-
vest. Tob. Abstr. 23(4):268.

DIALLO, I. and C.L. MULCHI. 1981. In-
fluence of time of infection by TMV
and TEV on agronomic, chemical and
physical properties of tobacco cv. Md
609. Tob. Sci. 25:1-5.

GOODING, G.V. JR. 1969. Epidemialo
gy of Tobacco Mosaic Virus on Flue-
Cured Tobacco in North Carolina.
North Carolina Expt. Sta. Tech. Bul.


TMV ordinary strain on the percent loss in
ide index, and crop value of flue-cured
*

Yield Grade Index Crop Value
ia) (f)

6a 73.43a 92.5a
ib 23.06b 46.00b
1b 23.43b 49.25b



ire not significantly different at 1% level by




No. 195. 14 p.

LEE, A.A. 1921. Observations on pre-
viously reported or noteworthy plant
diseases in the Philippines. Phil. Agric.
Rev. 14:422-434.


LUCAS, G.B. 1975. Diseases of Tobacco
(3rd ed.). Biological Consulting Asso-
ciates. Raleigh, North Carolina, 593 p.

LUNA, D.A., E.G. RAQUEL and S.G.
SUGUI. 1981. Screening tobacco for
resistance to mosaic. Philipp. Tob.
Abstr. 87.

PCARR, 1979. Philippine Recommends
for Tobacco. 127 p.

MATTHEWS, R.E.F. 1970. Plant viro-
logy. Academic Press. New York. 778p.


NORDAM, D. 1973. Identification of
Plant Viruses. Methods and Experi-
ments. Centre for Agricultural Pub-
lishing and Documentation. Wanengin,
Netherlands. 207 v.


Jan. & June 1983












PHYTOPATHOLOGICAL NOTE: INCIDENCE OF SUGARCANE RUST
(PUCCINIA MELANOCEPHALA H. & P. SYDOW) IN THE
VICTORIAS MILLING COMPANY DISTRICT
OCCIDENTAL NEGROS, PHILIPPINES IN 1982

R.J. SERRA, F.C. BARRED and A.P. TIANGCO

Respectively, Sugarcane Pathologist, Head, Variety Improvement and Crop Pro-
tection Units, and Director, Sugarcane Research Division, Victorias Milling Co., Inc.,
(VICMICO), Negros Accidental.

ABSTRACT

In a stratified random survey conducted from July to September 1982 at Vic-
torias Milling Co., milling district in Negros Occidental, Philippines, sugarcane rust
(Puccinia melanocephala H. & P. Sydow) was found frequently associated with Phil71-
226 and to a lesser degree with Phil58-260 and VMC67-611. The other commercial
varieties, viz, VMC71-238, Phil65-53, Phil71-15, Phil66-07 and the upcoming VMC71-
39 were found highly resistant to the disease.
The extent of infestation ranged between 40.0% 46.4% of the total area
planted to Phil56-226 which was about 3,367-4,243 hectares regardless of stratification
(lowland, intermediate and upland). Based on the characteristics and nature of occur-
rence, the disease was believed to have been endemic. The temperature, rainfall and
relative humidity were some of the major factors which favored the development of
the disease. Recommendations to manage the disease were included.

Under Philippine condition, sugarcane ciated only with two Phil varieties (Phil
rust normally occurs during the summer 56-226 and Phil56-260) in the province


Barredo (1980) confirmed the above ob-
servation and noted that the incidence
decreased with the advent of the rainy
season and the infected plants recover.
The disease was reported in the Philip-
pines in 1922, and was identified as
caused by Puccinia kuehnii (Krug.) Butler
(Lee, 1922; Ocfemia, 1931; 1939). Egan
(1980) commented that the rust species
present in the Philippines could be
P. kuehnii but recommended that the
identification be rechecked for confirma-
tion. In a survey done by Atienza and
Quimio (1981), it was reported that
P. kuehnii was found associated with spe-
cimens collected from Pampanga, Tarlac,
Cebu, Leyte, Iloilo, Capiz and Negros
province and was apparently the domi-
nant species causing sugarcane rust in the
Philippines. On the other hand, P. mela-
nocephala H. & P. Sydow was found asso-


pines.
However, the recent outbreak of
sugarcane rust in the Victorias Mill Dis-
trict could not be explained by either of
the previous reports and survey results.
Firstly, the incidence occurred during the
rainy months (early June to October) and
secondly, the symptoms and morpholo-
gical appearance differ from those of
P. kuehnii but seem to resemble those of
P. melanocephala. A similar incidence was
also noted in 1981 but was not properly
attended to. However, the infestation in
1982 was rather widespread and alarming.
Phil56-226, which is still the major varie-
ty in the district (and in the Philippines)
occupying a total area of 9,139 hectares
which is about 29% of the whole district
area was severely affected (Table 1).
It this regard, a survey was conducted
to determine the extent of the infestation












Table 1. Hectarage and percentage area
coverage of sugarcane varieties
planted at the VMC mill district
in Negros Occidental, Philip-
pines, in 1982.

Total area Percentage
Variety planted in coverage
hectares

1) Phil56-226 9,139 29.4
2) VMC67-611 8,042 25.9
3) Phil58-260 5,058 16.3
4) Phil66-07 4,470 14.4
5) VMC71-238 1,932 6.2
6) Phil65-53 309 1.0
*7) Phil67-23 218 0.7
8) VMC67-315 205 0.7
Total 29,374 ha.

and confirm the association of the rust
species with known symptoms and mor-
phological description. Other possible
contributing factors viz. relative humidity,
temperature and rainfall were likewise
taken into account.

MATERIALS AND METHODS

A stratified random sampling method
was used in the survey conducted from
July to September, 1982. The whole dis-
trict was stratified into three zones: low-


Table 2. Stratified frequency distribution of the reaction of 2-6 month-old Phil56-226
to sugarcane rust


Stratification Moderate Percent Severe Percent
frequency frequency


Jan. & June 1983


Phytopathological Note


land, the intermediate, and the upland.
From each of the strata, 9-10 representa-
tive haciendas were randomly selected as
survey areas based on the district's par-
cellary map. A total of 34 fields were sur-
veyed for the lowland area, 20 fields for
the intermediate and 28 fields for the up-
land. Infestation was rated moderate
when average leaf infection from the first
unfurled to the last functional leaf ranged
from 1.0-13.5% and severe when average
leaf infection ranged from 13.6-100%.
The frequency distribution was then used
to estimate the extent of infestation in
the district.
Samples were collected and brought to
the laboratory for examination and iden-
tification based on symptomatological ex-
pression and morphological appearance of
urediospores and teliotospores.

RESULTS AND DISCUSSION

Extent and Nature of Infestation
Based on the frequency distribution,
infestation ranged from 40.0%-46.4% of
the total area planted to Phil56-226
which totalled to about 3,367 has.-4,243
hectares (Table 2). Canes between 2-4
months at the onset of the infection were
severely affected while canes 5 months
old and above were least, if not affected
by the disease. Older canes seem to have
gradually gained resistance, in which case


Lowland
Intermediate
Upland


55.9
63.3
53.6


44.1
40.0
46.4
43.2


Total









Philippine Phytopathology


could be explored and utilized as a part
of an integrated control against sugarcar
rust (Liu, 1979). Hence, susceptible varie-
ties with excellent agronomic characteris-
tics could still be grown profitably.
The sudden widespread distribution of
the disease in alarming degree suggests
the possibility that it could have been
endemic and that the recent incidence
could be less attributed to any outside
source. Plant pathologists from Philsucom
agree with the above mentioned specula-
tions (through personal communication).
As a matter of fact they commented that
some of the specimens collected several
years back were found to be P. melano-
cephala. During a separate survey con-
ducted at the Hawaiian Philippines Mill
district about 17 km away from VMC,
they observed the same rust species
frequently associated with Phil56-226
during the same months of 1982.

Symptoms and Signs
The symptoms start as minute necro-
tic spots concentrated mostly on the
upper 2/3 of the leaf and apparent on
both surfaces of the infected leaves.
These spots increase in length with time
and later turn dark brown and coalesce
with each other forming bigger and larger
pustules. Both newly developed and rup-
tured pustules could be found on the
undersurface of the infected leaves. In-
fection was observed to occur from leaf
+ 2 to the oldest functional leaf, in in-


creasing severity. In some instances, only
the unopened leaf is spared from in-
fection.
These symptoms were commonly asso-
ciated with Phil56-226 but less with other
commercial varieties viz. VMC67-611 and
Phil58-260. VMC71-38 and Phil66-07
were highly resistant (0-5% leaf infection)
to the disease, even when planted adja-
cent to Phil56-226 highly infected with
rust.
Microscopic examination of leaf samples
collected from the infested field revealed
dark brown to cinnamon brown, echinu-
lated urediospores which are either ellip-
soidal or obovoidal. These were lined
with uniformly formed walls. Dark brown,.
two-celled teliotospores were likewise
observed, all of which were characteristics
ofP. melanocephala.
Based on these observations, the rust
species was identified asP. melanocephala
H. & P Sydow. This was confirmed by
Dr. H. Koike, a Research Plant Patholo-
gist of the U.S. Department of Agricul-
ture during his visit to the VMC Sugar-
cane Research Station last Nov. 5, 1982,
together with some Philsucom plant
pathologist.

Climatic conditions during disease
occurrence
The maximum and minimum tempera-
ture recorded from July to September
were 31.60C and 22.2 C, respectively
(Table 3). Moreover, rainfall data averaged


Table 3. Prevailing climatic conditions during the period of occurrence of suarcane rust
at VMC mill district1

Temperature (OC)
Rainfall Relative
Months (1982) Ave. Mx. Aw. Min. (mm) Humidity

July 31.5 23.0 146.2 82.3
August 31.6 23.1 248.5 81.9
September 31.2 22.2 188.6 83.0
'Data collected from the VMC weather station located at the Main Experimental Station, Victorias,
Negros Occidental.


Vol. 19









PhvtoDatholonical Note


194.4 mm during the same period. High-
est precipitation occurred during the
month of August at 248.5 mm. Liu and
Bernard (1979) reported that these condi-
tions are rather very conducive for the
germination of urediospores of P. melano-
cephala. These factors undoubtedly con-
tributed to the high incidence of the dis.
ease.


however, reducing the area planted to
Phil56-226 to avoid the "mono-variety
plantation system" will help prevent
epidemics.
Burning the trash of infested field
after harvest could be one of the easiest
and effective control measures to reduce
inoculum level.


January. Since an abrupt change of seases in the Philippines. Proc. 6th
variety could not be done, this system Cong. I.S.S.C.T., Baton Rouge, p. 183.
could be adopted temporarily. Ifpossible, 189.


r%









I


t Membership in ,ti pine Phytc
jn>

soiety-Te Editorial Board, howei
tions of exceptional merit. It may
articles of interest to the Society.
2. Manuscripts must be reports of ori
should have not been published elsi
accept or reject the manuscript is final
3. The manuscript should be typed on
throughout.
4. The author's name should follow th
and acknowledgements should follow
5. Papers other than Notes maybe org
tion, Materials and Methods, Result
Literature Cited.
6. In the text, citations should be bl
(1967) or (Ou and Nuque, 1967).
Nuque and Silva (1967) should appea
7. Literature citation should be in alp]
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Serials with Title Abbreviations mt
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8. Tables should be numbered consecut
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9. Figures should add clearly to an un.
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10. See latest journal of Philippine Phy
papers to be submitted to the journal
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THOLOGY published semi-annually in English, College, Laguna,
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PHIL. PHYTOPATHOLOGICAL SOCIETY, INC. UPLB-CA, College, Lagu
: PDM Press Inc. Don Roces Ave., Quezon
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