• TABLE OF CONTENTS
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 Front Cover
 Front Matter
 Information for authors
 Abstracts of papers accepted for...
 Some physical properties and suscept...
 The initial movement of abaca mosaic...
 Synthetic compost for spawn production...
 Cultivation of auricularia...
 Phytopathological note - Leaf blight,...
 A proposal: Compilation of host...














Title: Journal of Tropical Plant Pathology
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Permanent Link: http://ufdc.ufl.edu/UF00090520/00007
 Material Information
Title: Journal of Tropical Plant Pathology
Series Title: Journal of Tropical Plant Pathology
Physical Description: Serial
Language: English
Publisher: Philippine Phytopathological Society
Place of Publication: Philippines
Publication Date: 1966
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Bibliographic ID: UF00090520
Volume ID: VID00007
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electronic_oclc - 54382605
issn - 0115-0804

Table of Contents
    Front Cover
        Front Cover 1
        Front Cover 2
    Front Matter
        Title Page
    Information for authors
        Page i
    Abstracts of papers accepted for presentation at the third annual meeting of the Philippine phytopathological society, NSDB Pavilion, July 23-24, 1966
        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
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
    Some physical properties and suscept range of the abaca mosaic virus
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
    The initial movement of abaca mosaic infection among the stalks in a hill of abaca
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
        Page 36
        Page 37
    Synthetic compost for spawn production of agaricus bisporus
        Page 38
        Page 39
        Page 40
        Page 41
        Page 42
        Page 43
        Page 44
        Page 45
        Page 46
        Page 47
        Page 48
    Cultivation of auricularia polytricha
        Page 49
        Page 50
        Page 51
        Page 52
    Phytopathological note - Leaf blight, purple spot and chlorotic streak of sugarcane in Negros Island, Philippines
        Page 53
        Page 54
        Page 55
        Page 56
        Page 57
        Page 58
    A proposal: Compilation of host index
        Page 59
        Page 60
Full Text
DELFIN B. LAPIS
;' ; Dept. of Plant Pathology
College of Agriculture U.P.
College, Lamoa




VOL. II January and Jun, 66 Nos. 1 and 2


PHILIPPINE PHY F ATHOLOG.,

PUBLISHED BY
THE PHILIPPINE PHYTOPATHOLOGICAL SOCIETY



CONTENTS:

Abstracts of Papers Accepted for Presentation at the Third Annual
Meeting of the Philippine Phytopathological Society, NSDB
Pavilion, July 23, 24, 1966 .......................... 1

Some Physical Properties and Suscept Range
of the Abaca Mosaic Virus .............................. 22
Lydia Velasco-Magnaye and A. L. Eloja

The Initial Movement of Abaca Mosaic Infection
Among the Stalks in a Hill of Abaca ................ ..... 31
A. L .Eloja and M. T. Opefia

syntheticc Compost for Spawn Production of Agaricus Bisporus .... 38
Priscilla Rubio and R. V. Alicbusan

yVultivation of Auricularia Polythrica ........................... 49
Jane D. Borromeo and Don R. Reynolds

Phytopathological Note -
Leaf Blight, Purple Spot and Chlorotic Streak
of Sugarcane in Negros Island, Philippines ................ 53
J. R. Rivera and I. B. Cano


A Proposal: Compilation of Host Index ......... .......... ...











THE PHILIPPINE PHYTOPA'


Founded on October 0t962


The P. P. S. Co c. _
President, H. A. CUSTODIO, Bureau of Plant Induis U8 a
Retiring President, O. R. EXCONDE, University of the Phi ppmes, College, Laguna
Vice-President, MA. SALOME DEL ROSARIO, University of the Philippines, College,
Laguna
Secretary, R. G. DAVIDE, University of the Philippines, College, Laguna
Treasurer, IMELDA JOANO-QUINTANA, University of the Philippines, College, La-
guna (vice PRISCILLA CHINTE-SANCHEZ, effective July, 1966)
Editor-in-Chief, A. N. PORDESIMO, University of the Philippines, College, Laguna
(vice E. F. ROLDAN, effective July, 1966)

Councilors
VICTORIA MENDIOLA-ELA, University of the Philippines, College, Laguna (Luzon)
L. N. GIBE, Bacolod City (Visayas)
A. L. ELOJA, Bureau of Plant Industry, Davao City (Mindanao)

Sustaining Associate
VELSICOL, CHEMICAL CO., c/o ESFAC, Makati, Rizal



PHILIPPINE PHYTOPATHOLOGY
Official Organ of the Philippine Phytopathological Society

EDITORS
A. N. PORDESIMO, Editor-in-Chief, Department of Plant Pathology, University of
the Philippines, College, Laguna (vice E. F. ROLDAN, effective July, 1966)
A. L. MARTINEZ, Citrus Experiment Station, Bureau of Plant Industry, Lipa City
M. S. CELINO, Philippine Coconut Administration, Diliman, Quezon City
B. P. GABRIEL, University of the Philippines, College, Laguna
M. E. LOPEZ, Philippine Sugar Institute, Manila
F. A. AQUILIZAN, University of the Philippines, College, Laguna

BUSINESS MANAGEMENT
Business Manager, ROMULO F. P. QUEMADO, Union Carbide Phil., Inc. P.O Box
677, Manila (vice R. I. CAPINPIN, effective January, 1966)
Subscriptions: Cominunications should be addressed to Mrs. Imelda Joano-
-Quintana, College, Laguna. Subscription price: P2.00 per copy for domestic and
U.S.$1.00 elsewhere. The Philippine Phytopathology is published semi-annually
during the months of January and June with its first issue in January, 1965. Deliveries
overseas are not guaranteed; foreign mailings are made at the subscriber's risk.
Membership in The Philippine Phytopathological Society: Information concerning
membership in the Philippine Phytopathological Society will be supplied by the
Secretary upon request. Advertisements: rates may be secured from the Business
Manager. No endorsement of any statement of claims made in advertisements is
assumed by this Journal or by the Philippine Phytopathological Society.











INFORMATION FOR AUTHORS


At least one author must be a member of The Philippine Phytopathological
Society. A letter of transmittal from the responsible official within his institution
should preferably accompany any manuscript.

Manuscript: Two copies should be submitted, typed on 8 1/2 x 11 inch paper
double space throughout, including tables, legends, and citations. Ample margins
should be left on each side and bottom. Atithor's position, acknowledgments, ac-
ceptance date, etc., should follow author's name, and will not appear as footnote.
Papers other than Notes may be organized conveniently under: Abstract, Review
of Literature (if needed), Materials and Methods, Results, Discussion, and Literature
Cited sections. Further subdivisions of the Results section mqy be desirable.
Avoid footnotes. The page number and author's name should .appear in the
upper right-hand corner of each manuscript page. The author's institutional
address should appear beneath his name.

Tables should be numbered consecutively, and 'each typed on a separate page.
Tables must have descriptive headings and should be understandable without
reference to the text. Lower case superscript letters are to be used for footnotes
to tables. Pages containing tables should follow Literature Cited, and should be
numbered accordingly.

Figures (graphs, line drawings, and photographs) should add clearly to an
understanding of the paper. The size and arrangement of figures should corres-
pond to Journal page. Combine illustrations in composite cuts when possible, and
number each unit to correspond with the text figure reference, using consecutive
Arabic numerals. Label each illustration in pencil on the reverse side with the
figure number and author's name. Legends for figures should be typed together
on a separate numbered page following the tables.

For style details follow: Conference of Biological Editors, Committee on Form and
Style. 1964. Style Manual for Biological Journals (Second Edition). Amer. Inst.
Biol. Sci. Washington, D.C. 117 p. Authors are urged to have one or more col-
leagues read a manuscript critically before Submitting it for publication. Manus-
cripts and editorial correspondence should be sent to the editor-in-chief. Sub-
mission implies nonsubmission elsewhere'"nd (if accepted) no publication else-
where in the same form without consent.












ABSTRACTS OF PAPERS ACCEPTED FOR PRESENTATION
AT THE THIRD ANNUAL MEETING OF THE PHILIPPINE
PHYTOPATHOLOGICAL SOCIETY NSDB Pavilion,
July 23, 24, 1966


(Arranged alphabetically according to first author's surname)
Mycorrhiza from two Philippine plants. B. A. Advincula and
Don R. Reynolds. The two Philippine wild plants Aleurites tris-
perma Blco. and Angiopteris sp. commonly growing in Mount Ma-
quiling were found inhabited by endophytic mycorrhizal fungi of
vesicular-arbuscular and arbuscular type of endotrophic mycorrhiza,
respectively. Different culture media were used and several meth-
ods were employed to induce the growth of the fungus from the
root tissue. However, these attempts were not successful, hence
identification of the endophytes was not possible. Differential
staining of the fungus and the root tissues in 1% aqueous solution
of safranin and counterstained with 1% alcoholic aniline blue was
useful for comparative and descriptive observations.
Chemical control of soybean rust. C. R. Batoon and Luz
Rubia. A split-plot experiment was conducted to find a fungicide
that can effectively control soybean rust caused by Uromyces sojae.
Three fungicides (Shell Copper, Copper Lonacol, and Fungicide
658) were used at two different rates (3 and 5 g/gal of water) and
sprayed at 7-, 14-, and 21-day intervals.
Statistical analysis of the yield data showed no significant dif-
ferences between fungicide treatments. The differences between
the spraying intervals of 7 and 14, and 14 and 21 days were not
significant, but significant between 7 and 21 days. The difference
between the rate of applications 3 and 5 g/gal of water was not
significant, but the differences between any treatment and the con-
trol were significant.
Cultivation of Auricularia polytricha. Jane Borromeo. The
substrate used in the cultivation of A. polytricha (Mont.) Sacc. was
a mixture of sawdust and rice bran at 1:5 ratio containing 2 to 3%









PHILIPPINE PHYTOPATHOLOGY


brown sugar. The medium was placed in wide-mouthed bottles and
autoclaved for 1 hr at 20-lb pressure. Each bottle was seeded with
mycelial fragments obtained from two-week old cultures in malt agar
and incubated at room temperature for about a month until the
bulk of the substrate was almost completely covered with mycelial
growth. This constituted the spawn.
Limbs of Balete (Ficus retusa) and Anabiong (Trema orienta-
lis) were tested as wood substrate. For each species, two pieces,
each measuring about 6 inches in diameter and 3 ft long were
used. Holes of about 1 cm in diameter and in depth and distant
from each other vertically by 12 cm and about 9 cm on the circum-
ference were bored. Into each, a pinch of the spawn was intro-
duced. This was subsequently covered with bark plugs of the
same diameter. The seeded holes of one piece of each species
were sealed with paraffin while those of the other piece were left
unsealed. The wood logs were piled in criss-cross fashion, covered
with wet newsprints and kept under a shed. Watering was done
as often as necessary to keep the logs moist. Fructification were
produced after 3 months. The unsealed holes were easily acces-
sible to small insects while the bark plugs failed to remain in
place.
Influence of various proportions of sand to loam on the po-
pulation dynamics of Rotylenchus reniformis in bush "sitao".--
R. H. Calinga and A. V. Palo. Pot. experiments were conducted
to determine the influence of varying proportions of clay loam soil
and fine sand on the multiplication of the reniform nematode
(Rotylenchus reniformis Linford & Oliveira) in bush sitao [Vigna
(sesquipedales x sinensis)] No. 1. The ratios of sand to loam were
as follows: 4:0, 4:1, 4:2 and 4:3. The inoculum levels were 0
(control) and 2,000 larvae per pot.
At the end of the growing period of the host, the rate of re-
production of the nematodes in the soil increased with the in-
creasing proportion of sand to loam.
There was a significant difference in yield between the inocu-
lated and the control plants. Similarly, there was a significant dif-
ference in yield in the 4:0 and either the 4:1 or 4:3 ratios. The in-
teraction between the 2 levels of inocula and loam soil and sand
mixtures was significant.









ABSTRACTS


The serological relationship of the abaca mosaic virus with
other rod-shaped plant viruses. B. S. Castillo. A method of
preparing antiserum against AMV abacaa mosaic virus) is de-
scribed.
In cross-protection studies, antiserum of AMV was reacted
against antiserum preparations of FMV (Fresia mosaic), PV2
(Phaseolus virus II), GMV (Galtonia mosaic), HMV (Hyacinth
mosaic), CMV (Croccus mosaic), IMV (Irish mosaic), NMV (Nar-
cissus mosaic), NGV (Narcissus Grijis), OMV (Ornithogalum mo-
saic), SMV (Sugarbeet mosaic), TBV (Tulip break), OnMV (Onion
mosaic), PXV (Potato X), PSV (Potato S), PMV (Potato M), PYV
(Potato Y), and TMV (Tobacco mosaic).
Microprecipitin tests at 1:20 dilution was used in the studies.
A method of purifying AMV on corn is also described.
Serological and physical properties indicated that OMV and
AMV are closely related. Electron microscopic studies showed rod
particles for these two viruses. CYV (Cucumber yellows) and AV
(Aspermy virus) are closely related but neither is related to AMV.
Electron micrograph showed that CYV and AV particles are
spheres.
The zonate chlorosis of citrus. C. S. Celino, U. V. Molino,
R. E. Cortez and A. A. Salibe. A disease whose symptoms closely
resemble those described as characteristic of zonate chlorosis in
Brazil was observed in citrus groves in Batangas and Laguna prov-
inces, in the Bicol region, and in Oriental Mindoro. The typical
symptoms are concentric chlorotic areas on mature leaves. The
same symptoms develop in green fruits but apparently the fruits
are not as much affected in the Philippines as they are in Brazil.
The zonate spots are small at first but may enlarge to about an
inch in diameter. The varieties most severely affected in the Phil-
ippines are Szuwuikom, Ladu and Szinkom mandarin (Citrus reti-
culata Blanco); sweet orange (C. sinensis Osbeck); Calamondin
(C. madurensis Loureiro); and pumelo (C. maxima Merrill).
When seedlings of Ladu mandarin were exposed to natural in-
oculation by placing them under affected trees of Szuwuikom man-
darin, all seedlings developed zonate chlorosis symptoms within 75
days. Young seedlings of different citrus types were also exposed
to natural inoculation in the same fashion. Difference in the sus-









PHILIPPINE PHYTOPATHOLOGY


ceptibility of these different varieties was visible and a rating sys-
tem was made that permitted to establish the following decrescent
order of susceptibility: Marsh seedless grapefruit, Szuwuikom
mandarin, sweet orange, sour orange, Troyer citrange, Rough.lem-
on, Eureka lemon, trifoliate orange, Comprida citron and C. ma-
crophylla.
Preliminary trials on its control where Szuwuikom mandarin
in potted plants were sprayed with a miticide (Chlorobenzilate
25%), an insecticide (Malathion 57%.), and a fungicide (Cuprox
50%) every 12 days and were subsequently subjected to inocula-
tion indicated that the test plants were protected only when the
miticide was used. Those sprayed with the insecticide and fungi-
cide developed more lesions than the non-sprayed control plants.
Apparently the disease is associated with the presence of certain
mite species that may cause the disease either by introducing a
toxin or a localized virus into the plant tissue. Determination of
mite species that may cause the disease by introducing either a
the Lipa Experiment Station.
Psorosis of citrus. R. E. Cortez and D. M. Nora. Symp-
toms resembling those described for psorosis, were noted in trees
of certain citrus varieties. These are bark scaling, blind pocket,
concave gum, and oak-leaf pattern on young leaves. Some infected
trees were indexed at the Lipa Experiment Station using sweet
orange seedlings as indicator. All inoculated plants showed the typ-
ical flecking symptom on young leaves as described for psorosis.
Further indexing work included apparently healthy looking trees
to determine the incidence of psorosis among the commercially
grown varieties. Results of this study indicate that out of 196
trees consisting of 40 varieties obtained from different citrus-grow-
ing areas of the Philippines, 30% were found to be carrying the
psorosis virus. Varieties found infected were Szinkom, Ponkam,
Szuwuikom, and Kishin mandarin (Citrus reticulata Blanco); King
mandarin (C. nobilis Loureiro); Santa Cruz mandarin (C. unshiu
Marcovitch); Valencia, Pineapple, Ming Lau Chiang and Washing-
ton Navel orange (C. sinenis Osbeck); Marsh seedless grapefruit (C.
paradisi Macfadyen); and Sunwuilak and Amoy Mantan pumelo
(C. maxima Merrill). Apparently, there also exist psorosis-free
lines of these different varieties.









ABSTRACTS


Reaction of citrus types and varieties to exocortis virus. R.
E. Cortez and A. A. Salibe. Exocortis or scaly butt is a virous dis-
ease of trifoliate Poncirus trifoliata Raf. and some of its hybrids,
Rangpur limes and other mandarin-lime (Citrus limonia Osbeck),
and some other citrus types. It is characterized by the stunting of
trees and scaling of the bark of the intolerant rootstocks. Sensitive
varieties may also develop symptoms of yellowing and splitting of
the bark of young branches. Certain selections of Etrog citron
(C. medical L.) show leaf symptoms.
The exocortis disease presently has a limited importance to the
citrus industry of the Philippines because intolerant citrus types
are not used as rootstocks. But it may become as important prob-
lem in case trifoliate, Troyer citrange and other varieties are used
as rootstocks.
A survey of virous diseases in citrus groves of the Philippines
revealed exocortis symptoms in the rootstock [possibly Kusaic lime
(Citrus limonia Osbeck)] of some trees of Szinkom mandarin (C.
reticulata Blanco) and in the branches of Tahiti lime trees (C. la-
tifolia Tanaka).
From various citrus areas, 196 outstanding trees representing
different scion varieties grown in the Philippines were selected and
indexed for the presence of the exocortis virus. Rangpur lime and
Etrog citron were used as indicator varieties. Three test plants
were used to index each of the selected trees. Results already
available indicated the presence of the exocortis virus in 26% of
the trees. Infected trees were: 4 out of 15 Szinkom mandarin (re-
presenting 26.6%); 1 out of 3 Ponkam mandarin (33.3%); 1 Clemen-
tine mandarin; 9 out of 16 Valencia orange (56.2%); 1 out of 2
pineapple orange (50.0%); 3 out of 4 Marsh seedless grapefruit
(75.0%); 1 out of 2 Eureka lemon (50%); 5 out of 7 Tahiti lime
(71.4%); 1 Tenhai pumelo; and 1 Ming Lau Chiang orange. These
results indicate the existence of lines of these citrus varieties that
are infected and free from the exocortis virus. In most cases, in-
fected trees are symptomless carriers of the virus and propaga-
tions from these trees using exocortis-intolerant rootstocks may
result in great losses to the citrus grower.










PHILIPPINE PHYTOPATHOLOGY


In the indexing program, differences in the incubation period
and in the severity of symptoms in the indicator plants suggest the
existence of different strains of the exocortis virus.
Influence of soil temperature on the development and sex ratio
of Meloidogyne incognita. R. G. Davide and A. C, Triantaphyllou.
- Nematode development and sex ratios were determined at tem-
peratures of 15, 20, 25, 30, and 35 C. In each of 5 temperature
tanks, 20 tomato plants, var. Rutgers grown in 4-inch clay pots
were placed in water-proof glazed pots. Each plant was inoculated
with 400 larvae of M. incognita. Observations on nematode devel-
opment at each temperature were made by examining one plant
from each treatment at various time intervals. When the majority
of the nematodes were found to reach maturity at any temperature
level the sex of the nematodes was determined.
The rate of development was influenced by the temperature at
which the plants were grown. Within 10 days after inoculation, the
majority of the nematodes recovered from plants at 30 C and 35 C
were adult females and in 13 days they were already producing
eggs. Most of the nematodes at 25 C reached adulthood 13 days af-
ter inoculation and started producing eggs 2 to 3 days later. At 20
C most of the nematodes became adult females 19 to 27 days after
inoculation and started producing eggs within 30 days. Nematodes
in plants at 15 C reached the adult stage in 38 to 50 days and pro-
duced eggs 60 days after inoculation.
The percentage (5 to 9%) of males among the sexually differ-
entiated nematodes was relatively high at the low temperature level
of 15 C. At all other temperatures the males constituted less than
1% of the sexually differentiated nematodes present in the roots.
Plant-parasitic and soil nematodes associated with lowland
rice fields. R. G. Davide, O. R. Exconde and F. D. Fuentes. A
survey of plant-parasitic and soil nematodes in several lowland
rice fields in Laguna, Rizal, Quezon, and Bicol Region was made
during the months of February and April, 1966. Soil samples col-
lected from 39 localities showed 11 genera of nematodes asso-
ciated with rice plants at various stages of growth. These are
Dorylaimus, Tylenchus, Tylenchorhynchus, Radopholus, Helicoty-
lenchus, Trichodorus, Aphelenchus, Hoplolaimus, Pratylenchus,
Xiphinema, and Longidorus. Dorylaimus and Tylenchus were most









ABSTRACTS


common in 16 and 9 localities, respectively. Tylenchorhynchus,
Radopholus, and Helicotylenchus were found in 3 localities; Tri-
chodorus, Aphelenchus, and Hoplolaimus in 2 localities; Pratylen-
chus, Xiphinema and Longidorus in one locality. Soil samples from
9 localities were completely free of these nematode genera.
Bacterial wilt resistance on 16 tomato lines. J. R. Deanon,
Jr. and B. P. Rodriguez. Sixteen lines of tomatoes selected from
previous screening test by the Vegetable Crops Section were fur-
ther evaluated for resistance to bacterial wilt during the 1965 dry
season.
At fruiting stage (65 days from germination) lines 1169 and
5010 were observed to be the most resistant while at turning stage,
lines 1169 and 1207 appeared to be the most resistant.
Line 1169 registered the lowest bacterial wilt index. It had
also the least number of plants affected by the disease.
Line 5015 had the greatest equatorial fruit diameter while line
5013 had the most number of marketable fruits. However, the
heaviest yield of marketable fruits was obtained from line 1169.
Some viruses transmissible to, and causing mosaic or mosaic-
like symptoms on abaca. A. L. Eloja and Lydia Velasco-Magna-
ye. Based on host range and gross symptomatology, the viruses
transmissible to, and causing mosaic or mosaic-like symptoms on
abaca may be classified into four groups, viz., abaca mosaic virus
(AMV), grass mosaic virus (GMV), batad (Coix lachryma Jobi)
mosaic virus (BMV), and Crotolaria mosaic virus (CMV).
AMV is the most prevalent and destructive on abaca. It causes
typical severe mottling, some degree of leaf malformation, and
stunting of plants. Its natural reservoirs are abaca, Canna indica
and Maranta arundinaceae. On the last two species, AMV also in-
duces a severe type of mosaic. It has been experimentally trans-
mitted by several aphid species and by sap inoculation to corn,
Digitaria sanguinalis, and Echinochloa colona.
GMV has been isolated from corn and grasses particularly
Echinochloa colona, Digitaria sanguinalis, Rottboellia exaltata, Im-
perata cylindrica and Paspalum conjugatum. On abaca, C. indica,
and M. arundinacea, GMV induces very mild symptoms which are
distinct from those of AMV. On corn it is usually more severe than









PHILIPPINE PHYTOPATHOLOGY


AMV but on D. sanguinalis and E. colona, the symptoms produced
by AMV and GMV are indistinguishable.
BMV is similar to GMV in almost all respects except that GMV
does not infect batad (C. lachryma-Jobi L.). In fact, among the
four virus groups only BMV can infect batad.
GMV is the only virus that has dicot and monocot hosts. While
the host range of all the three other viruses are confined to mono-
cots, GMV has been transmitted to Nicotiana tabacum, N. glutinosa,
Commelina benghalensis, Gomphrena globosa, Lycopersicon escu-
lentum, and corn. On abaca the symptoms produced by GMV dif-
fer appreciably from those by AMV. The spindle-shaped yellowish
streaks on the leaves and petioles, which are so typical in AMV in-
fection do not appear in GMV-infected abaca.
The initial movement of abaca mosaic infection among the
stalks in a stool of abaca. A. L. Eloja and M. T. Opefia. An
attempt was made at the Davao Experiment Station, Davao City,
to study the initial movement of the abaca mosaic virus in abaca
hills. Naturally infected abaca stools ranging in age from 6 months
to about 3 years were dug, their underground connections deter-
mined, and the individual corms or rootstocks separated. The larger
corms were divided into a number of seedpieces depending on the
size and number of eyes in these corms, while smaller ones were
planted in toto. All the seedpieces derived from each hill were
properly identified, planted individually, and observed critically
for germination and appearance of mosaic symptoms.
Among the 53 infected hills, infection in 36 or 67.92% started
in mother stalks, while in 16 or 30.19%,, infection started in the
suckers. In one hill (1.98%), the mother plant and three suckers
were observed to be showing mosaic symptoms at the same time
making it impossible to determine the pathway of infection.
In the 16 hills with infected suckers, movement of the virus to
other stalks in the same hill was considered to take place in 13 or
81.25% of these hills. On the other hand, the virus appeared to
move only in 9 or 27.1%. of the 36 hills with mother-stalk infection.
No virus movement was considered to take place in the remaining
73.9% of those hills with infected mother plants.
SWhen 2 or more stalks in a hill were showing mosaic symp-
toms, majority of the stalks in that hill were already invaded by









ABSTRACTS


the virus, but in hills where only 1 stalk was noticeably infected,
the virus appeared confined only to the stalk manifesting the symp-
toms.
Some evidence suggests that an abaca corm may only be par-
tially invaded by the abaca mosaic virus.
The relationship between Echinochloa and abaca mosaic vi-
ruses. A. L. Eloja and Ma. Salome del Rosario. Echinochloa
mosaic virus (EMV) was readily transmitted by sap inoculation
and by Aphis gossypii Glover and Rhopalosiphum maidis (Fitch.).
It was experimentally transmitted to abaca, Canna indica, Maran-
ta arundinacea, corn, Echinochloa colona, Digitaria sanguinalis and
Paspalum conjugatum, all of which except the last mentioned spe-
cies are also susceptible to abaca mosaic virus (AMV). The symp-
toms produced by EMV were similar to those produced by AMV
on the first three species, more severe on corn, and indistinguish-
able from those caused by AMV on E. colona and D. sanguinalis.
The physical properties of EMV were closely similar to those of
AMV. Reciprocal cross-protection tests between the two were ne-
gative but serological tests with each other's antisera and with
sugarcane mosaic virus antiserum were positive. These together
with their close similarities in symptomatology and host range,
physical properties, and methods of transmission were considered
sufficient to establish strain relationship between the two viruses.
Pathogenicity and cultural behavior of Ustilago maydis. O.
R. Exconde, Gregorio M. Lopez and S. A. Raymundo. The corn
smut fungus, Ustilago zeae (Beck.) Unger was successfully grown
in artificial culture medium. Of the several media tried, abundant
growth was observed in potato-sucrose-malt-extract agar. The op-
timum temperature for growth of the fungus was 28 C; the opti-
mum pH was 8. Sporidia produced in vitro culture had an average
size of 3.08 x 20.0 microns. Spores from smut balls had an average
diameter of 8.9 microns.
Corn plants inoculated with pure culture of the organism ex-
hibited symptoms of the disease within 10 days after inoculation.
Test of susceptibility of 4 varieties showed that Philippine Hybrid
No. 3 was the most susceptible. Inoculation of 7 plant species re-
lated to corn yielded negative results.









PHILIPPINE PHYTOPATHOLOGY


SThe mode of infection by stem rot fungi. S. P. Y. Hsieh and
S. H. Ou. A cut stem method was developed to study the mode
of infection of Helminthosporium sigmoideum Cav. and H. sigmoi-
deum var. irregulare Cralley & Tullis, the causal organisms of stem
rot disease of rice. Cut stems of field-grown or potted rice plants
at flowering stage were used. The cut stems were about 30 cm
long with an internode and a basal node. The method of inocula-
tion follows: bits of mycelium-sclerotia from PDA culture were
placed on leaf sheath with or without wounded slits and on stem
with or without punctures. The causal organisms hardly pene-
trated through unwounded tissue of the rice plant and only a small
lesion, if any, developed. In wounded leaf sheath or culm, they
incited infection readily. The entire internode became rotted and
sclerotia formed in 10 days on susceptible varieties. Identical
results were obtained from cut stems and standing stems when
inoculation through wounds was employed. The cut-stem-wound
inoculation was found very useful, simple and rapid. This can be
used in pathogenicity test and in screening for resistant varieties.
Further study revealed that appressoria were formed abund-
antly by both organisms upon hyphal contacts with the surface of
leaf sheath or stem. The formation of appressoria was not specific.
They could be formed in covered slides, cellophane, and many grass
species but not on filter paper and agar. Infection cushions were
formed only by H. sigmoideum and constituted its major infection
organ. The formation of infection cushions was non-specific. It
was noted on many non-host grasses but not on the glass slides or
other non-living materials.
Detached leaf technique for blast inoculation. H. T. Hsu and
S. H. Ou. A detached leaf technique was developed and found
useful for testing resistance of rice plants to the blast disease
caused by Piricularia oryzae Cav.
Leaves of rice plants were cut into sections of about 6 cm long.
Four to 6 leaf sections were arranged on the filter paper sufficiently
wetted with culture solution in petri dishes. Another filter paper
with the central area (4 x 5 cm) removed was placed over to hold
the edges of the leaf sections in place between the two filter pa-
pers. After inoculation with spore suspension the petri dishes were
covered and incubated at a temperature ranging from 21 to 23 C.









ABSTRACTS


Typical blast. lesions developed on leaf sections of susceptible va-
riety within 4 days after inoculation. Similar results were ob-
tained on inoculated rice leaves undetached from the source of the
leaf sections.
Monosodium phosphate, 0.01 M at pH 6.8 was found satisfac-
tory for detached leaf culture. Benzimidazole, 60-80 ppm, was the
most suitable chemical for maintaining the green color of excise
leaves. Detached leaves retained the green color longer under in-
direct light than under dark or direct light. Temperature higher
than 26 C caused severe damage to the detached leaves.
The small quantity of plant materials and the small space
needed in this inoculation technique are advantageous in certain
studies on the blast disease.
Unsuitable host response of coffee to several species and iso-
lates of the root-knot nematode, Meloidogyne. C. P. Madamba
and J. M. Sasser. The effects of four different Meloidogyne spe-
cies on coffee (Coffea arabica L.) were studied. Species used in-
cluded one isolate each of M. arenaria (Neal) Chitwood, M. incog-
nita (Kofoid & White) Chitwood, and M. javanica (Treub.) Chit-
wood, and several isolates of M. hapla Chitwood. Inoculum level
was held constant at 10 egg masses and the experiment was con-
sidered as a factorial design, species and isolates being the two
factors.
The top and root weights of all Bourbon coffee seedlings ino-
culated with the above species and isolates were lighter than those
of the non-inoculated control 28 days after inoculation. Lengths
of the various lateral root categories of inoculated plants were like-
wise generally shorter than those of the controls. At 56 days after
inoculation, only seedlings inoculated with any of the three isolates
of M. incognita have recovered. Only top weights of seedlings ino-
culated with either M. hapla or any of the three isolates of M. java-
nica were significantly lower than those of the controls. But roots
of these seedlings were either thickened, swollen or galled as in
the case of those inoculated with M. hapla. Measurements of the
various root categories showed that seedlings inoculated with M.
javanica had significantly less and shorter primary and secondary
lateral roots. Additional studies suggested that Bourbon coffee.
seedlings were less tolerant than the Typical variety.









PHILIPPINE PHYTOPATHOLOGY


A comparison of host response indicated that Bourbon seed-
lings inoculated with M. incognita isolates reacted differently from
one another, whereas differences among seedlings inoculated with
M. javanica isolates were not significant.
Various root malformations and discolorations were observed
in inoculated coffee seedlings. A certain M. hapla isolate induced
typical hapla galls and giant cell formation in Bourbon coffee seed-
lings, but the nematodes had not developed beyond the second
stage. Further tests showed that 2 out of 6 M. hapla isolates in-
duced galling in Bourbon coffee. Root malformations and signi-
ficant reduction in lateral root length and number resulted in re-
duced leaf size in all inoculated plants and leaf chlorosis in some.
Larval development beyond the second stage was rare in coffee
roots inoculated with the various Meloidogyne species and isolates.
Majority that have entered the roots developed beyond the migra-
tory second stage but were sexually undifferentiated up to 56 days
after inoculation. In M. hapla, all advanced second stage larvae
and adults observed at 56 days after inoculation were males.
Results of these studies further substantiate previous findings
that failure of the root-knot nematode to mature in roots of un-
suitable host plants does not preclude damage to these plants.
These studies also suggest presence of biotypes in M. incognita
and M. hapla.
Yield response of some vegetable and field crops to soil fumi-
gation for the control of plant parasitic nematodes. C. P. Ma-
damba, J. R. Deanon, Jr., G. B. Bantoc, Jr. and C. G. Goseco. -
Several nematocides were tested for the control of several nema-
tode species of the genera Meloidogyne, Helicotylenchus, Hoplolai-
mus, Tylenchorhynchus, and Hemicycliophora that abound in soil
at:the UPCA Central Experiment Station where the following crops
were grown: cucumber, var. Pixie; okra, var. Smooth Green; cow-
pea, var. Los Bafios No. 6; lima bean, var. Habas; bitter gourd,
Sta. Rita strain; peanut, var. Spanish White; and flue-curing to-
bacco, var. Golden Harvest. Results showed significant increase in
yield of the crops. Yield response in cucumber and okra were
highly significant. Weight and number of fruits based on 15 bi-
weekly pickings in cucumber showed that plants grown in soil
treated with Dowfume W85 (ethylene dibromide), Nemagon 20G









ABSTRACTS


(1-2 dibromo-3-chloropropane), Agrene (benzyl-N-dithiocarbamate),
and Zinophos (phosphatic nematocide) exceeded markedly the over-
all yield of the controls. Similarly, yield of okra grown in plots
treated with the above chemicals, D-D (dichloropropane-dichloro-
propene), Dowfume MC-2 (methyl bromide) and Union Carbide
Experimental No. 21149 10G were significantly higher than those
of the controls. There were also strong indications of increased
yield in the other crops tested.
Most of the soil fumigants induced early maturity in cucum-
ber such that the peak of harvest was generally attained three
weeks earlier than that of the control.
Additional data on cucumber, okra, lima bean, cowpea, and
peanut also showed beneficial carry-over effects of soil fumigation
for at least two successive growing seasons.
These results demonstrated the limiting role of plant parasitic
nematodes in crop production. It is apparent that under condi-
tions of severe infestations, nematode population must be reduced
to a certain point to realize more profits from crops.
Wheat rust at the Cagayan Valley Rice and Corn Experiment
Station. J. M. Manglicmot and 0. M. Lawas. The performance
of 1,340 wheat varieties and strains, composing 1,421 accessions, in-
troduced from 24 countries were evaluated for adaptability to local
conditions and for rust resistance.
During the growing seasons between 1962 and 1965, however,
the low incidence of rust did not permit evaluation of these acces-
sions for rust resistance. Moreover, further tests were made im-
possible by the gradual loss of accessions occasioned by their in-
ability to produce sufficient number of seeds for subsequent trials.
This loss indicated clearly that wheat cannot be produced in the
area as profitably and successfully as rice or tobacco.
Resistance of isolates of Piricularia oryzae to fungicides. -
A. S. Manzanilla, Jr. and 0. R. Exconde. The ability of 6 monos-
porial isolates of Piricularia oryzae Cav. to acquire tolerance to
Arasan 75, Orthocide 75, Blasticidin S, and Panogen 15 was deter-
mined thru serial transfers on maximal non-lethal concentrations
(MNLCs) of the fungicide-media. When subcultured serially on
fungicide-free medium, all the resulting tolerant isolates, except
isolate 10 on Blasticidin S medium, retained their capacity to grow









PHILIPPINE PHYTOPATHOLOGY


on the maximal non-lethal concentration of the fungicide medium.
Some isolates grew on fungicide medium with concentration that
was 2 ppm higher than its original maximal non-lethal concentra-
tion, while the more tolerant isolates grew on fungicide-medium
with doubly higher concentration than their originally-tolerated
MNLCs. Serial transfers on the MNLCs of Panogen 15 medium and
the gradually-increased concentrations of Orthocide 15 medium
caused cultural variations on 3 isolates. Continuous growing on
gradually-increased concentrations of Orthocide 15 medium caused
some apparent changes in the appearance of the conidia of 1 iso-
late. Tolerance to fungicide did not change the capacity of the iso-
lates to sporulate on steamed water hyacinth.
A virus associated with vein yellowing and apparent stunting
- A. L. Martinez. Vein yellowing and apparent of sweet potato.
stunting of sweet potato in some plantings in Lipa City were found
associated with a virous infection. The virous nature of these abnor-
malities was determined by sap-transmission. The vein yellowing
on the leaves of sap-inoculated plants was observed in 3 to 5 weeks
following inoculation. The possibility that this virus is related to
the sweet potato feathery mottle virus or the internal cork virus
is being investigated.
Exocortis virus in Philippine citrus. A. L. Martinez and N.
M. Sebastian. Until May, 1965, exocortis in Philippine citrus was
thought to be restricted to the Szuwuikom mandarin. This virus
is now known to occur in four other varieties, viz., Ladu, Pineapple
orange, Szinkom, and Valencia orange. Detection of exocortis was
made possible with the use of Etrog citron as indicator which
showed symptoms within 1 to 6 months following inoculation.
In the indexed trees, 90% of Szuwuikom, 30% of Ladu, 10% of
Szinkom, 100% of Pineapple orange, and 60% of Valencia were
found infected. The principal means of spread of exocortis in
groves have been mild because of the use of tolerant rootstocks.
Severe effects occurred when susceptible rootstocks were adopted.
Mechanical transmission of a citrus virus to an herbaceous
plant. A. L. Martinez and N. M. Sebastian. Trees of Szinkom
mandarin which were found carrying tristeza-seedling yellows virus
complex contained a virus or viruses readily transmitted to white
sesame. The virus has been recovered from young leaves of citrus









ABSTRACTS


trees. The symptoms induced on inoculated white sesame seed-
lings composed of vein clearing followed by a mosaic pattern, dis-
tortion and reduction in size. The virus became more invasive to
white sesame by continued passage thru the same plant. Attempts
to transmit the virus from white sesame to other herbaceous spe-
cies and to citrus seedlings failed. Its relation to any of the known
citrus viruses cannot yet be determined.
Wood rotting fungi: Poria. E. M. Mendoza and C. V. Arenas.
- Twelve species of Poria, 10 from Mount Maquiling and 2 from
Mount Banahaw were tentatively identified based on Lowe's classi-
fication. Three of these already identified to species are Poria stra-
minea, P. vincta, and P. tricolor. The remaining 9 species which
have not yet been identified are simply designated as species 1, 2, 3,
etc. for convenience in referring to them.
Reaction of rice varieties to the blast disease in six regions of
the Philippines. S. H. Ou, F. L. Nuque and J. P. Silva. The
upland short row blast nurseries were used in testing several hun-
dreds of rice varieties in six cooperating stations located in differ-
ent regions of the Philippines to identify varieties with broad spec-
trum of resistance and to study the physiologic race patterns of
Piricularia oryzae Cav.
Five varieties, viz., Te-tep, D25-4, Kam Bau Ngan, Dular, and
Pah Leuad 29-8-11 exhibited a broad spectrum of resistance to
physiologic races at all stations. These may be used in crossing
with high yielding but blast susceptible varieties to incorporate re-
sistance. Another 20 varieties showed resistance in most of the
regions. Of the 12 Seed Board varieties included in the test, FB
121 proved to be the most resistant followed by BE-3. All the up-
land varieties were susceptible to blast.
Differences of race patterns in six stations may be noted on
several varieties. For instance, Ta-poo-cho 2 and Ladang were
highly resistant in Southern Luzon, Central Luzon, Bicol Region,
Northern and Southern Mindanao but were highly susceptible in
Northern Luzon and Western Visayas.
Correlation of resistance to bacterial leaf blight of rice at seed-
ling and flowering stages. S. H. Ou, F. L. Nuque and J. P. Silva.
- One hundred and nine varieties were inoculated with isolate B72
of Xanthomonas oryzae both at seedling (4-5 leaves) and flowering









PHILIPPINE PHYTOPATHOLOGY


stages. Three expanded leaves at the seedling stage and the flag
leaf at flowering were inoculated by needle puncturing at the mid-
dle point between the tip and the base of each leaf. Readings on
the size of lesion and other symptoms (pale yellow leaves and
"kresek") of the seedling were taken 20 days after inoculation.
The results showed a positive correlation (r = 0.8495) in re-
sistance or susceptibility between the two stages. A corresponding
scale of disease intensity between the two stages has been worked
out. Reaction at either stage can gauge the degree of resistance of
a variety.
This finding has made convenient the screening for varietal
resistance, selecting hybrid population in breeding program, study-
ing inheritance of resistance, etc. as the plant may be tested at
any of the two stages.
Inheritance of resistance to blast disease. S. H. Ou, F. L.
Nuque, Fe Divinagracia and J. P. Silva. Six resistant and 5 sus-
ceptible varieties were crossed to study the mode of inheritance of
resistance to the blast disease. The resistant varieties were Katak-
tara DA 2, Chianung Yu 280, K10B28-1, Ta-poo-cho 2, GP231 x H012,
and Pah Leuad 111. The susceptible varieties were Khao Tah Ha-
eng 17, Taichung Native 1, Tjere mas, BPI-76 (sensitive) and BPI-
76 (non-sensitive, Bicol strain). Twelve isolates of Piricularia ory-
zae, viz., 1-110, 1-120, 1-129, 1-143, 1-142, 1-116, 1-104, 1-31, 1-42,
1-29, 1-92, and I-9 were used.
F, seedlings from all crosses between resistant and susceptible
parents showed resistant reaction against single isolate of the fun-
gus. In 51 out of 68 experiments, the F2 seedlings segregated into
3:1 ratio, indicating that blast resistance is controlled by a single
dominant gene. However, 9:7 and 15:1 ratios were likewise ob-
tained indicating two-gene difference between resistant and suscep-
tible parents. These data also suggest that 2 pairs of genes are in-
volved in some crosses. Results obtained from F, progenies of 10
selected crosses gave additional evidence supporting the monogenic
mode of inheritance. The F2 resistant lines verified at the F. gene-
ration closely fitted to the segregation ratio of 1 breeding true for
resistance to 2 segregating lines. In the backcrosses, a 1:1 ratio of
resistant to susceptible was consistently obtained. This indicates








ABSTRACTS


that inheritance of resistance to the blast disease is governed by a
single dominant pair.
In addition to these genetic results, it was also demonstrated
that the resistance can be easily transferred by the backcross
method to susceptible but otherwise desirable varieties. Incorpo-
rating the blast resistance into currently used varieties may be
achieved without difficulty. One should, however, select the re-
sistant parents with broad spectrum of resistance to physiologic
races.
Growth and yield of rice plants infected with tungro virus. -
M. K. Palomar and K. C. Ling. Rice plants of varieties BPI-76
and IR9-60 at different ages were artificially inoculated with the
tungro virus using the leafhopper, Nephotettix impicticeps Ishihara,
as vector.
The percentage reduction in height of infected BPI-76 were
31, 25, and 11 for plants inoculated at 10, 30, and 60 days old, re-
spectively; while those of IR9-60 were 52, 35, 15, and 4 for the
corresponding ages of 15, 30, 45, and 60 days. The number of
tillers produced by infected plants varied. Tillering was reduced
when the plants were inoculated at 60 days. There was no signi-
ficant difference between the total number of leaves produced by
healthy and diseased plants.
Loss in yield from Tungro-infected IR9-60 was higher than that
of BPI-76. In both cases, infected plants produced fewer, lighter,
and often dark brown grains. The reduction in yield of IR9-60
was 74% when infected at 15 days, 55% at 30 days, 50% at 45 days,
and 31% at 60 days; whereas in BPI-76 yield was reduced by 61%
when infected at 10 days, 26% at 30 days, and 18% at 60 days.
Philippine Auricularia. D. R. Reynolds. "Taingang daga"
or jelly fungi of the genus Auricularia are kr.own locally as an in-
gredient in "pansit" and vegetable dishes. Although the dried fruit
bodies command a fair price, there is no commercial cultivation
of this organism in the Philippines. Reinking reported 2 species as
being sold in Philippine markets and have been experimentally
grown on a number of local woods. Methods have been developed
in China for wood cultivation.
Dr. N. G. Teodoro lists some 13 species for this genus in his
1937 "Enumeration of Philippine Fungi." Of the 10 species recog-









PHILIPPINE PHYTOPATHOLOGY


nized in Lowy's monograph, 8 are recorded for the Philippines.
Two or 3 of these are evidently suitable for human consumption
and commercial production.
Lowy utilized internal morphology to separate the species. The
Philippine species may be tentatively identified according to the
length of the hair on the abhymenial side of the fruit body.
Three recently recognized diseases of sugarcane in Negros Is-
land, Philippines. J. R. Rivera and I. B. Cano Three new or
unrecorded diseases of sugarcane in this country were found to
occur in various places of Negros Occidental in 1964. These are
leaf blight, red leaf spot or purple spot, and chlorotic streak.
Leaf blight caused by a fungus, Leptosphaeria taiwanensis
(Mat. et Yam) Yen et Chi, was observed to be common on cane
varieties POJ 3016, Phil 54-42, B37/172 and H37/1933 during August
to December.
Red leaf spot or purple spot was found affecting POJ 3016, NCo
310, Co 440, Phil 54-60, Phil 53-33 and Alunan cane.
Chlorotic streak which is attributable to a virus was first ob-
served on H38-2915 and B43/62 in low-lying poorly-drained fields
of Hda. San Jose, La Castellana on October 28, 1964 by the senior
author and Dr. C. A. Wismer of HSPA, Hawaii. Further ocular
survey of the fields at a later date showed that POJ 3016 and Alu-
nan canes were also affected by the disease. Preliminary studies
on transmission so far undertaken indicate that the disease is
transmitted through cane cuttings. The disease appears more pre-
valent in poorly-drained areas and in ratoon crop. After several
surveys and field visits, 4 varieties were found highly susceptible
to the disease. These cane varieties tentatively classified accord-
ing to their reaction to chlorotic streak are: H38-2915 and B43/62,
heavily infected (leaf streaking on four or more leaves); POJ 3016
and Alunan, moderately infected (leaf streaking at least on two
leaves).
Identification of the virus in Centrosema pubescens through
transmission, host range and physical property studies. Ma. Sa-
lome del Rosario, O. R. Paguio and E. C. Clemente The mosaic
virus of Centrosema pubescens Benth. was identified through a
study of its modes of transmission, host range and physical prop-
erties. The virus, tentatively designated as Centrosema pubescens









ABSTRACTS


mosaic virus (CPMV), was readily transmitted either by sap or by
aphids, but not through the seed. Aphis gossypii Glover and A.
craccivdra Koch vectored the virus from diseased Centrosema to
healthy ones.
Chenopodium amaranticolor Coste and Reyn. was found to be
a local lesion host of the virus. Except this plant, the host range
of CPMV appears to be restricted to the Leguminosae.
Studies on the physical properties of CPMV revealed that it is
an unstable virus. It could not withstand a dilution of more than
1:1000. Its thermal death point lies between 55 and 60 C for 10 min-
utes. The virus loses infectivity after 48 hours in vitro and 5 days in
vivo under ordinary room temperature. It was also found inacti-
vated by a 60-minute exposure to 70% alcohol and formaldehyde at
1:100 concentration; and by a 10-minute exposure to 95% alcohol,
and nitric acid at 1:100 to 1:1000 concentrations.
This study showed that CPMV is very similar to the Centro-
sema mosaic virus reported by van Valsen and Crowley in Papua
and New Guinea.
The tristeza virus complex of citrus. A. A. Salibe, R. E. Cor-
tez and F. R. Husmillo. The tristeza virus is considered to exist
in a number of strains. The more virulent strains apparently occur
in mixtures with milder strains. They all induce decline and death
of susceptible scion-rootstock combinations, typical examples of
which are trees of sweet orange and tangerines on sour orange
rootstock. They all induce leaf-vein clearing and stem pitting on
plants of the Key Lime type. Other citrus types may also develop
mild to severe wood pitting when infected, depending on the de-
gree of intolerance of their tissue and the virulence of the virus
strain they are infected with. Young seedlings of certain citrus
types, like Eureka lemon and sour orange that have tissues highly
sensitive to tristeza virus are severely affected. They develop yel-
low leaves and remain stunted which together constitute the symp-
tom known as seedling yellows.
Graft and insect inoculation using the aphid Toxoptera citri-
cidus Kirk collected in commercial groves, resulted in decline and
death of young plants of Szinkom mandarin on sour orange root-
stock within 6 to 8 weeks after inoculation. Budwood collected









PHILIPPINE PHYTOPATHOLOGY


from 62 trees of different citrus varieties in the Batangas area,
Bicol region, Oriental Mindoro, and Mindanao was graft ino-
culated to lime seedlings. All test plants developed symptoms
characteristic of tristeza. Budwood from some of the tree sources
was used to inoculate Eureka lemon, Sour orange, Orlando tangelo
and Rangpur lime. All induced seedling yellow symptoms on Eu-
reka lemon and Sour orange. Others induced yellowing of leaves,
stunting, and stem pitting on the other indicator plants.
The current status of the ring spot disease of coffee in the
Philippines. R. B. Valdez. A survey on the incidence of ring
spot on over 2,000 introduced and local Arabica coffee trees was
conducted. A total of 128 different accessions obtained from 17
coffee-growing countries and 7 accessions obtained from 7 prov-
inces in the Philippines showed ring spot symptoms. The percent-
age of infected plants increased yearly from 40.7 in 1962, 49.0 in
1963, 64.9 in 1964 to 72.8 in 1965.
Six different types of ring spot symptoms on the leaves have
been observed and described, viz-, chlorotic ring spot, necrotic com-
plete ring spot, necrotic incomplete ring spot, yellow ring spot,
oak-leaf pattern and vein necrosis.
Transmission through seed has been further established in
Coffea excelsa with 16.9% infection obtained within 1 year and 9
months after the seeds were planted. In C. arabica, seed transmis-
sion has been demonstrated for the first time with 25% infection
obtained 5 months after the seeds were planted and in 2 cases the
symptoms were observed on cotyledonous leaves.
Post infection development of Meloidogyne. Helen Zapanta
and C. P. Madamba. Studies on the post-infection development
of Meloidogyne incognita (Kofoid & White) Chitwood under green-
house conditions showed that infective second stage larvae can
reach maturity as early as 15 to 16 days after penetration into roots
of a susceptible tomato variety (line 3015). The majority of the
adults attained the egg-laying stage 22 to 28 days after penetration,
although some were observed at this stage as early as 17 to 21 days
after entry.
The second larval molt occurred 15 to 16 days after penetra-
tion. The third molt followed within a few hours and the fourth, 2









ABSTRACTS 21

to 5 days later. Gall formation was observed as early as the fifth
day after the larvae have entered the root.
No males were found in this study, suggesting that the nema-
tode reproduces parthenogenetically.
The slight differences of these findings from those in other
countries with respect to the time required for the development
of the different larval stages suggest variations in the developmental
pattern of Meloidogyne species according to the geographical area
where they are found. The development of root knot nematodes
is apparently faster in the Philippines.















SOME PHYSICAL PROPERTIES AND SUSCEPT RANGE
OF THE ABACA MOSAIC VIRUS


LYDIA VELASCO-MAGNAYE and A. L. ELOJA
Davao Experiment Station, Davao City


ABSTRACT

A number of plant species were tested for natural AMV infections and
for susceptibility to the same virus. Field sources of the virus were con-
fined to only three species, viz., Musa textilis Nee (cultivated and wild),
Canna indica, L. and Maranta arundinacea L. On these, the symptoms
produced were severe mottling, reduction of leaf size and stunting of the
plant. The virus was experimentally transmitted to cultivated abaca, C.
indica, M. arundinacea, Echinochloa colonum (L.) Link., Zea mays L., Rott-
boellia exaltata L., Digitaria sanguinalis (L.) Scop., Imperata cylindrica (L.)
Beauv., Setaria palmifolia and to several wild abaca species. On corn, the
virus induced mild mottling which tended to disappear later as the infected
plant aged. AMV on E. colonum, R. exaltata, I. cylindrica, D. sanguinalis,
and S. palmifolia produced typical mosaic symptoms.
Nicotiana tabacum L., N. glutinosa L., Lycopersicon esculentum Mill., Cap-
sicum annum L., Gomphrena globosa L., Chenopodium amaranticolor Coste
and Reyne, Cucumis sativus L., Phaseolus vulgaris L., Vigna sesquipedalis L.,
Centrosema pubescens Benth., Crotolaria juncea L., Calopogonium muconoides
Desv., Paspalum conjugatum Berg., Coix lachryma-Jobi L., and Commelina
benghalensis L., were not infected by AMV in both sap and aphid ino-
culations.
The dilution end-point of crude sap from AMV-infected corn was between
1:1,1000 and 1:5,000 and the thermal inactivation point was between 50 and
55 C. At room temperature of 26 to 32 C, infective sap was still infectious
after 10 hr but not after 24 hr. Frozen crude sap remained infective for
2 weeks while sap expressed from frozen infected leaves for 3 weeks.



Earlier workers (Calinisan, 1938; Ocfemia and Celino, 1938;
and Juliano, 1951) reported that abaca mosaic virus (AMV) was
transmissible only by aphid inoculation. Consequently, no investi-
gations on the in-vitro properties of the virus were made and even
studies on its suscept range were limited.









ABACA MOSAIC VIRUS


Eloja et al. (1962) published the first account on the transmis-
sion of AMV by sap inoculation. It was at the Rothamsted Experi-
mental Station in England where the physical properties of AMV
obtained from the Philippines was first studied and reported (Eloja
and Tinsley, 1963).
A separate study (Benigno and del Rosario, 1965) on some of
the physical properties of AMV was carried out simultaneously with
our present work here in the Philippines which may be regarded as
the origin and natural "habitat" of this virus.

MATERIALS AND METHODS

The virus. Two AMV isolates, one obtained by Eloja et al.
(1962) and the other by Eloja and Tinsley (1963), were used in this
work. Later, however, these two isolates could not be distinguished
from each other on the basis of suscept range and symptom expres-
sion by their suscepts.
The isolates were maintained by regular transfers to corn, var.
Yellow Flint. Occasionally, they were test-inoculated to abaca to
see that there was no change of the virus as indicated by the symp-
toms produced on abaca seedlings.
Test plants. The different species of test plants were ger-
minated from seeds. They were grown in an insect-proof green-
house which was sprayed wtih aphicides once in 2 weeks. Only
Maranta arundinacea was propagated from rootstocks. After inoc
ulation, the experimental plants were kept in small insect-proof
cages which were similarly sprayed with aphicides.
Determination of natural suscept range. The natural suscept
of AMV was determined by inoculating corn and abaca seedlings
with viruses from plants and weeds which were naturally infected
or suspected to be naturally infected with a virus. During the 4-
year period (1957 to 1961), a number of species were collected and
tested to determine if they were naturally harboring AMV.
Determination of experimental suscept 'range. Several plant
species were artificially inoculated with AMV to test their suscep-
tibility. The first inoculation was by sap from infected corn, var.
Yellow Flint. When the plants thus inoculated developed no symp-
toms, 3 similar trials were made. When all these failed, aphid
transmission by either the corn aphid, Rhopalosiphum maidis









PHILIPPINE PHYTOPATHOLOGY


(Fitch) or the cotton aphid, Aphis gossypii Glover was resorted to.
In either case the aphids were allowed only short acquisition feed-
ing. At least four trials were made using aphids. In each trial
whether it was by sap or by aphids at least 6 plants were inoculated.
If no symptoms were observed in any of the inoculated plants 30
to 45 days after inoculation, retrieval by both sap and aphid trans-
mission were made using the symptomless inoculated plants as
source of inoculum. This was done to determine if any of the in-
oculated species were symptomless suscepts of AMV.

RESULTS
Natural sources of AMV. Inoculation of abaca seedlings by
aphids which had fed on naturally-infected C. indica, M. arundi-
nacea, cultivated abaca as well as wild abaca resulted in the pro-
duction of typical symptoms of abaca mosaic (Fig. 1). Inocula-
tions utilizing infected plant sap as inoculum were not as success-
ful possibly due to the presence of inhibitors in the sap of these
species or to the low virus content of the sap. The symptoms of
naturally-infected Canna, Maranta, and abaca were not any differ-
ent from those of artificially-infected plants. At a distance natu-
rally-infected Canna (Fig. 2) and abaca were usually yellowish.
Viewed closer they were smaller than healthy plants and the leaves
were severely mottled. Spindle-shaped streaks were evident on
the leaf blade. The leaves were more brittle than those of healthy
ones and the leaf margins were usually curled inwards and wavy.
Infected M. arundinacea exhibited a dark green mottle, so that the
leaves of infected plants were darker than those of healthy ones,
although much reduced in size (Fig. 3).
Mosaic viruses from pepper (Capsicum annum), tobacco (Ni-
cotiana tabacum), Commelina benghalensis and a ringspot virus
from Gomphrena globosa were not communicated to abaca.
Natural mosaic infections from corn (Zea mays), Digitaria
sanguinalis, Echinochloa colonum, Coix lachryma-Jobi, Andropogon
halepensis, Paspalum conjugatum, Imperata cylindrica, Rottboellia
exaltata and Setaria palmifolia were transmitted to abaca but the
symptoms were not typical of AMV infection. The symptoms con-
sisted of 1 to several light greenish spindle-shaped streaks on the








ABACA MOSAIC VIRUS


*1 i


Fig. 1. Abaca leaf infected with AMV (left).
At right is healthy leaf.










PHILIPPINE PHYTOPATHOLOGY


Fig. 2. Leaf of Canna infected with AMV (left) and
healthy leaf (right). Note mottling.


r *;
r~-JI 1
%~












ABACA MOSAIC VIRUS


T- -4
8.: ( aF


Fig. 3. Leaves of A. arundinaceae showing mild (left) and
severe (center) mottling. At right is healthy leaf.


^ "r"









PHILIPPINE PHYTOPATHOLOGY


abaca leaf blade. Some leaves often appeared without any discer-
nible symptoms.
A mosaic virus naturally occurring on Crotolaria juncea and
other Crotolaria species was aphid-transmitted to abaca but not
by sap. The symptoms produced on abaca were atypical of AMV
infection. Crotolaria mosaic virus on abaca produced irregularly-
shaped light green areas on the leaf blade. The absence of spindle-
shaped streaks served as a diagnostic feature of Crotolaria mosaic
virus on abaca.
Hosts infected by artificial inoculation. C. indica, M. arun-
dinacea, and abaca were susceptible to artificial inoculation with
AMV. The symptoms resulting from artificial and natural infec-
tions are similar to those described above.
Corn, var. Yellow Flint, was also artificially infected with AMV.
Infected corn seedlings exhibited a mild mottle which tended to
disappear with age of the infected plants.
AMV was likewise communicated to D. sanguinalis, E. colonum,
I. cylindrica, S. palmifolia and R. exaltata. Severe mosaic symp-
toms resulted when these were artificially inoculated with AMV.
Artificially-infected plants were indistinguishable from those nat-
urally infected with viruses which when transmitted to abaca
caused only very mild symptoms.
AMV was neither transmitted to nor recovered from artificially
inoculated Nicotiana tabacum, N. glutinosa, Lycopersicon esculen-
tum, Capsicum annum, Gomphrena globosa, Chenopodium amaran-
ticolor, Cucumis sativus, Phaseolus vulgaris, Vigna sesquipedalis,
Centrosema pubescens, Crotolaria juncea, Calopogonium muco-
noides, Commelina benghalensis, Coix lachryma-Jobi and Paspalum
conjugatum.
Physical Properties. Ten ml samples of crude sap from in-
fected corn untreated and heated at temperature of 40, 45, 50, 55
and 60 + 1 C for 10 min gave 66.7, 49.1, 15.8, 0, and 0% infection
on corn, respectively. The thermal inactivation of AMV is, there-
fore, between 55 and 60 C.
Crude sap of AMV-infected corn when inoculated immediately
after extraction gave 73.8% infection but the same sap inoculated
after 10 hr at room temperature of 26 to 32 C infected only 36.1%
of the inoculated corn seedlings. When inoculated 24 hours after









ABACA MOSAIC VIRUS


extraction it was no longer infective. Infection still resulted after
inoculation with infective sap stored for 2 weeks in the freezer
compartment of a refrigerator but the same inoculum kept for 3
weeks in the freezer lost its infectivity. Sap from infected corn
leaves similarly frozen for 3 weeks were still infective.
The dilution end-point of AMV was between 1/1,000 and 1/
5,000. At 1/1,000 dilution infective crude sap gave 37.5% infection
while the undiluted sap gave 66.7%..

DISCUSSION

Although abaca is susceptible to some mosaic viruses naturally
occurring on a number of cultivated plants and weeds, the typical
AMV was isolated only from C. indica, M. arundinacea, and cul-
tivated as well as wild abaca. Both the natural and experimental
suscepts of AMV appear confined to the monocots, indicating a
narrow range of suscepts. No dicot and local-lesion host was found.
We do not consider abaca mosaic as caused by cucumber mo-
saic virus (CMV) as suggested by Calinisan (1934) and Holmes
(1939) because some plant species which are usually infected
readily with CMV and its strains were not susceptible to AMV.
Our failure to isolate AMV from weeds like E. colonum, P. con-
jugatum, A. halepensis, D. sanguinalis, and Rottboellia exaltata
which are very common in abaca plantations, is noteworthy. This
finding and the limited natural sources of AMV underscore the
significance of using disease-free planting materials and the inten-
sive roguing of infected plants in abaca mosaic control. Field
population of C. indica, M. arundinacea and wild abaca are con-
sidered insignificant sources of AMV. This leaves only infected
abaca itself as the main source of inoculum. The importance of
weeds as sources of inoculum has perhaps been over emphasized,
however, understandable considering that many grass weeds are
suscepts of AMV. The absence or rarity of natural AMV infections
on these weeds may be explained only after thoroughly studying in
detail the habits of the insect vectors as they affect the spread of
the virus in the field.
Our data on the physical properties of AMV in this study are
much higher than those reported by Eloja and Tinsley (1963). The
discrepancy may be due to differences in conditions under which











PHILIPPINE PHYTOPATHOLOGY


the two investigations were conducted. Either the much colder
temperature, lower light intensity, and shorter daylight in England
may have rendered the test plants less susceptible, the virus less
virulent, or the infected plants have lower virus content. From this
view point it is important to indicate the conditions under w-k.ih
the investigations were undertaken when reporting on the physical
properties of a virus.


LITERATURE CITED

BENIGNO, D. B. and MA. SALOME E. DEL ROSARIO. 1965. Mechanical trans-
mission of the abaca mosaic virus and some of its physical properties.
Phil Agr. 49: 197-210.
CALINISAN, M. R. 1934. Notes on a suspected "mosaic" of abaca in the Phil-
ippines. Phil. J. Agr. 5: 225-258.
CALINSAN, M. R. 1938. Transmission experiments of abaca mosaic. (Progr. Rept.
No. 1). Phil. J. Agr. 9: 309-313.
ELOJA, A. L., L. V. MAGNAYE and J. A. AGATI. 1962. Studies on the abaca
mosaic disease. I. Sap transmission of the abaca mosaic virus. Phil. J.
Agr. 27: 75-84.
ELOJA, A. L. and T. W. TINSLEY. 1963. Abaca mosaic virus and its relation-
ship to sugarcane mosaic. Ann. Appl. Biol. 51: 253-258.
HOLMES, F. O. 1939. Handbook of phytopathogenic viruses. Burgess Publ. Co.,
Minneapolis, Minn., 221 p.
JULIANO, JORGE P. 1951. A study of the mosaic disease of abaca, or Manila
hemp plant (Musa textilis Nee), with special reference to sources of ino-
culum and possible transmission of the virus by mechanical means. Phil.
Agr. 34: 125-132.
OCFEMIA, G. O. and M. S. CELINO. 1938. Transmission of abaca mosaic. Phil.
Agr. 27: 593-598.













THE INITIAL MOVEMENT OF ABACA MOSAIC INFECTION
AMONG THE STALKS IN A HILL OF ABACA

A. L. ELOJA and M. T. OPERA
BPI, Davao Experiment Station, Davao City


ABSTRACT

Among 53 infected hills observed, infection in 36 or 67.92% started
in mother stalks, while in 16 or 30.19%, infection started in the suckers.
In 1 hill the mother plant and 3 suckers exhibited mosaic symptoms
at the same time so that it was impossible to determine where in-
fection had started. In 16 hills with sucker infection, movement of
the virus, to other stalks in the same hill was considered to take
place in 13 or 81.25%. On the other hand, the virus appeared to
move in only 9 or 25% of the 36 hills with mother stalk infection. No
virous movement was considered to take place in the remaining 75%.
Where 2 or more stalks in a hill were showing mosaic symptoms,
majority of the stalks in that hill were already invaded by the virus,
but in hills where only 1 stalk was obviously infected, the virus
was usually confined to that stalk manifesting the symptoms. In some
instances both healthy and diseased seedpieces were obtained from
stalks that were apparently infected through movement of the virus
from an originally infected stalk.


One of the most effective measures employed in the control
of the abaca mosaic is the roguing of diseased plants as soon as
these are noted. Two methods of roguing are generally recognized.
"Complete roguing" refers to the removal of the entire hill wherein
an infection has been observed, regardless of the number of stalks
showing mosaic symptoms. "Partial roguing" on the other hand
refers to the removal of the diseased stalk or stalks only. In so do-
ing, however, it is inevitable that some healthy stalks that are ob-
structing the removal of the diseased stalk including its corm,
should also be removed.
As to which of the two methods should be practised has al-
ways been a subject of controversy. Abaca planters contend that
complete roguing is uneconomical and impractical. The Bureau
of Plant Industry, on the other hand, has always been in favor of









PHILIPPINE PHYTOPATHOLOGY


complete roguing, believing that partial roguing is not only ineffec-
tive but even dangerous. It maintains that because of the systemic
nature of plant viruses, it is likely that healthy-looking stalks in
an infected hill already contain the abaca mosaic virus and that
these stalks will eventually manifest mosaic symptoms. In the
meantime the disease will have spread to the other healthy plants
in the plantation. This argument, however, although anchored on
sound phytopathological principles is mainly presumptive because
there have been no investigations on the movement of the abaca
mosaic virus in a hill of abaca.
This study was therefore conducted from 1959 to 1962 at the
Davao Experiment Station. It was mainly designed to obtain some
information on the movement and distribution of the abaca mo-
saic infection in a hill of abaca. It was hoped then that any in-
formation on this facet of the abaca mosaic problem would be of
help in resolving the controversy between the adherents of partial
and complete roguing.

MATERIALS AND METHODS

A study with closely similar objectives was started as early as
1953 by Mr. B. S. Castillo who used whole abaca corms planted in
large cans and kept inside insect-proof cages. Later the present
workers used corms planted directly in soil inside a large green-
house. In these two instances the plants did not grow normally
so that no worthwhile results could be obtained.
In 1959, it was decided to utilize infected field-grown plants
taken from abaca lots within the vicinity of the Davao Experiment
Station laboratory. The plants in these lots were critically exam-
ined weekly for mosaic infection. Any hill with one or more
stalks showing unmistakable symptoms of mosaic infection was
dug up immediately, cleaned of roots and soil materials, and washed
so that the interconnections between stalks could be shown in de-
tail. For convenience, interstalk relationship were recorded as
follows: The first stalk in the hill which eventually gave rise to
all the other stalks was designated as "mother" (M), thus MI, M2
and M, referred to the first, second and third (in the order of
height) stalks that originated from a single planting material. The
stalks immediately arising from the "M" stalks were designated as









INITIAL MOVEMENT OF ABACA MOSAIC INFECTION


"daughters" (D), those arising from the "D" were "granddaugh-
ters" (G) and those arising from "G" were "great granddaughters"
(GD). Stalks arising from the same parent were referred to as
"sisters."
Once the interstalk 'relationships had been recorded and each
stalk appropriately labelled, all the stalks including the infected
ones were separated, the rootstocks extracted and then prepared
for planting. Bigger rootstocks were divided into seedpieces while
smaller ones were planted whole. All the seedpieces prepared from
an infected hill were planted either in large earthen pots or di-
rectly in the soil inside the greenhouse. The plants were observed
regularly for date of germination and appearance of mosaic symp-
tonis.

RESULTS AND DISCUSSION
SMovement of Infection. A total of 53 infected hills ranging
from 6 months to over 3 years were dug, separated and planted.
The number of stalks to a hill ranged from 3 to 31. There were
more hills with mother (M) stalk infections,- than those with sucker
infections. Of the 53 infected hills, 36 or 67.92% were with in-
fected M stalks while only 16 or 30.19% were with infected suck-
ers. The 16 hills with sucker infections consisted of 12 hills with
daughter (D) stalks diseased; 3 with diseased granddaughters (G),
and 1 hill with diseased great granddaughter (GD) stalks.
In one of the 53 infected hills, the mother stalk and 3 daugh-
ters were all diseased so it was difficult to determine where infec-
tion had started.
Virous movement had apparently taken place in 23 or 43.4%
of the 53 hills. There were more cases of virous movement among
those hills with sucker stalk infections than among those with mo-
ther stalk infections. The virus was considered to move in 13 or
81.25% of the 16 hills with sucker infections. On the other hand,
the virus appeared to move in only 9 or 25% of the 36 hills with
mother infections. In the remaining 27 hills (75%), mosaic infec-
tion was confined to those stalks that were originally diseased.
In hills with mother stalk infections there was necessarily no
upward movement of infection, but lateral movement between mo-









PHILIPPINE PHYTOPATHOLOGY


their stalks arising from 1 planting material occurred in 2 hills, in
addition to downward movement to the daughter stalks.
Movement of infection in hills with sucker infections was tri-
directional-downward from the infected stalks to their daughters,
upward from daughters to mothers, and lateral between sister
stalks through their mothers, or original planting material in the
case of upward, and direct lateral movements, respectively. How-
ever, downward movement occurred in only 3 cases but movement
upward following the ascending order of relationship occurred in
10 out of the 13 cases. In most instances, infection reached only
the mother stalk but in 1 instance it went as far as the grandmo-
ther and in 3 instances it went laterally to the sister stalks.
It will be noted from the preceding observations on sucker-
infected hills that the abaca mosaic virus apparently moves upward
from daughter to mother stalks more frequently than vice versa.
This fact may perhaps help to explain why there were less instances
of virous movement in mother stalk infections. The nature of these
infections necessarily precludes the possibility of upward move-
ment of the virus.
This observation appears to be contrary to what was expected.
It was held likely that abaca mosaic infection would move more
frequently from mother to sucker rather than the reverse, because
the younger stalks were deriving sustenance at one time or another
from the mother plants. Virous movement is generally believed
to follow the translocation of food materials within the plant.'
Number of diseased stalks in a hill and its relation to method
of roguing. Of the 53 infected hills observed, there were 3 in
which more than 1 stalk were showing mosaic symptoms 2 in-
fected stalks in 2 hills, and 3 infected stalks in the third. Mosaic
infection had moved in all these 3 hills which consisted of 44 stalks
from which 64 seedpieces were obtained. Upon germination 33 or
51.56% came out diseased. The 33 diseased seedpieces came from
24 or 54.54% of all the stalks.
The other 50 hills had only 1 infected stalk in each hill. In 14 or
28% of these hills the abaca mosaic virus appeared to have already
moved to other stalks, but in the remaining 36 hills (72%) infec-
'Bawden, F. C. 1956. Plant viruses and virus diseases. 3rd ed. Chronica Bo-
tanica Company, Waltham, Mass., 355 p.









INITIAL MOVEMENT OF ABACA MOSAIC INFECTION


tion was still confined to the original infected stalks. The 50 hills
consisted of 377 stalks which gave rise to 601 seedpieces. On plant-
ing and germination, 67 or 17.78% of the stalks yielded infected
seedpieces while 108 or 17.97% of the seedpieces came out mo-
saicked.
It appears that it would indeed be uneconomical to rogue out
completely hills having only 1 infected stalk, since less than 20%
or 1/5 of the stalks in these are infected. Partial roguing would
be practical and effective provided that the rootstocks of the in-
fected stalks are carefully removed.
In hills where more than 1 stalk are already showing mosaic
symptoms, partial roguing would be ineffective since majority of
the stalks may already be infected. The chances of Ihe disease re-
curring in the remaining healthy-looking ones would be great and
the danger of these hills serving as source of inoculum would be
imminent.
Possibility of obtaining planting materials from infected hills.
- Of the 665 seedpieces obtained from the 53 infected hills, only
141 or 21.2% came out diseased. The remaining 78.8% were
healthy. This observation indicates the possibility of obtaining
disease-free planting materials from infected hills. In places where
the supply of planting materials is a critical problem, rogued-out
hills may serve as source of planting materials. It is obvious that
the stalks showing mosaic symptoms should be automatically dis-
carded since all seedpieces derived from them will be diseased.
The healthy-looking stalks, however, will yield healthy plants as
well as a few infected ones. Those infected will manifest mosaic
symptoms immediately or soon after germination. Through a sys-
tem of periodic critical examination and roguing, especially during
the first 2 months after germination, all those infected will be eli-
minated in due time.
Evidence of partial rootstock invasion by the abaca mosaic
virus. In 10 out of the 53 infected hills studied there was some
evidence that the abaca mosaic virus had only partially invaded
some rootstocks. The 2 typical examples below illustrate this phe-
nomenon:
1. Hill No. 10 consisted of 15 stalks 1 mother stalk (Mi),
8 daughter (D) stalks (D, to D8), and 6 granddaughters (GD) aris-









PHILIPPINE PHYTOPATHOLOGY


ing from D1, D2 and D,. Stalk D1 was mosaicked. On germination,
the 7 D and the 6 GD stalks gave rise to all healthy plants. The 3
seedpieces from DI (MID a MIDb and MD,) which were originally
infected came out all diseased. One of 3 seedpieces (M.) derived
from the M1 stalk showed mosaic symptoms 6 days after germina-
tion but the other 2 (MIb and M o) remained healthy until the ter-
mination of observation 4 months after planting.
2. Hill No. 17 (Fig. 1) had 15 stalks Mi with Di to D6; Ma
with Di to D4; and 3 G's arising from MIDi, M2Di; M2D2. M1 was in-
fected. All the 4 seedpieces obtained from M1 were observed to be
infected 2 to 11 days after germination, MD la 20 days after germina-
tion but MID, remained healthy. Similarly M2d and M2, were observed
to be mosaicked within 9 and 33 days after germination, respectively,
but M2 and M, did not develop any mosaic symptoms.


M D3


Fig. .l Diagrammatic representation of Hill No. 17 showing downward (M1 to MID1) and lateral
(MI to J,) movement of infection and the apparent partial invasion of two stalks (MID and i~)
by the abaca mosaic virus. (O.P. x original planting material; = developed mosaic symp-
toms; () remained healthy).









INITIAL MOVEMENT OF ABACA MOSAIC INFECTION


This evidence of partial invasion of abaca rootstocks by the
abaca mosaic virus was noted in 8 other hills where movement ot
virus had apparently taken place. It was observed only on those
stalks to which the virus had apparently moved after it had com-
pletely invaded and manifested its symptoms in one of the other
stalks in the hill.


REMARKS AND RECOMMENDATIONS

In abaca hills where only 1 stalk is showing mosaic symptoms,
it is likely that the abaca mosaic virus is still confined to that 1
stalk manifesting the symptoms, so that "partial" roguing may be
effective provided that the infected stalk, together with its root-
stock, is removed. After thus removing the infected stalk, the hill
should be marked and watched closely for the chance appearance
of mosaic symptoms in any of the remaining stalks.
If 2 or more stalks in a hill are infected, "complete" roguing
should be resorted to. Partial roguing would not be practical since
most of the stalks in that hill are likely to be invaded already by
the abaca mosaic virus.
In places where the supply of planting materials is a critical
problem, rogued-out hills may serve as source of planting materials
provided all infected rootstocks are immediately discarded and pro-
vided further that the seedpieces coming from the healthy-looking
stalks are observed critically for the appearance of mosaic symp-
toms. Any infected plant should be eradicated immediately.














SYNTHETIC COMPOST FOR SPAWN PRODUCTION
OF AGARICUS BISPORUS


PRISCILLA RUBIO and R. V. ALICBUSAN
Undergraduate thesis student and Instructor IV, respectively, Department
of Plant Pathology, U.P. College of Agriculture, College, Laguna.
This work is a portion of the senior author's undergraduate thesis.


ABSTRACT
Synthetic compost for spawn production of Agaricus bisporus (Lang.)
Singer was prepared from rice straw, dried banana leaves, dried water lily
to which was added in series ammonium sulfate, urea, calcium sulfate, and
superphosphate at varying proportions. Composting was accomplished with-
in 20 days at 50 C in an incubator. In the process of decomposition, peculiar
odor, change in texture and loss in weight of plant materials were noted.
The fungus grew rapidly in water lily plated in petri dishes or contained
in bottles followed, in descending order, by banana leaves; rice straw and
banana leaves; rice straw; banana leaves and water lily; banana leaves and
water lily; rice straw alone; and rice straw and water lily.
Preliminary studies of growing Agaricus mushroom using either the
plated or bottled spawn of synthetic compost yielded mushrooms in an
air-conditioned room with temperature range of 14-20 C and 50 to 68%
relative humidity.


Horse manure and straw are the standard constituents of com-
posts used in the cultivation of Agaricus mushrooms. Horse ma-
nure provides nutrients for the mushrooms; straw supplies carbon
and fibrous structures necessary for aerobic growth of the myce-
lium. Composting makes the nutrients from the horse manure and
straw readily available to the organism. But in certain countries
horse manure is either scarce or costly. In the Philippines, for
instance, horses are rare and only small quantities of manure can
be obtained. Furthermore these horses are commonly fed with
molasses. It is believed that good quality manure should come
from healthy work horses which are fed not with molasses but
with straw.









AGARICUS BISPORUS


In order to remedy the scarcity and lack of good-quality horse
manure, substitutes have been suggested by earlier workers who
attempted to produce an economical and good synthetic compost
by using farm wastes and inorganic chemicals.
Lambert (1929) and Hein (1930) who used nitrogen fertilizers
and phosphates as substitutes for horse manure showed that nor-
mal mushroom could be produced although yield was low.
Waksman and Reneger (1934) prepared synthetic composts by
adding alfalfa and ammonium phosphate to the straw to facilitate
its decomposition by the addition of "green material" with a high
moisture content. They also prepared composts of tobacco stem
and straw. In any case, the yields were variable.
Sinden (1938) prepared synthetic composts consisting of
straw, urea, and wheat. Urea was selected as a source of nitrogen
,because it left no inorganic residues; wheat was added to help re-
tain the heating capacity of the compost. The best yield he ob-
tained per sq ft of bed surface was about 1/3 less than that of ma-
nure compost. p e-, 0-,-
As a result of extensive experimentation, Stoller (1943) asserts
that a ton of synthetic compost with 70% moisture should con-
tain about 13 lb N, 4 lb P20O and 10 lb K2O.
Bone meal, calcium cyanide, soil, baled straw and chopped
tobacco composed the synthetic compost of Rettew and Thompson
(1948). Yoder and Sinden (1954) made use of ground cobs and
hay as substitutes for horse manure. In order to obtain yield
equal to or better than that obtained when horse manure compost
was used, they found that it was necessary to control the maximum
temperature reached during pasteurization and the circulation of
fresh air. Under such conditions, the yield was from 2 to 21/2 lb
per sq ft. Singer's (1961) own experiment showed that admixtures
with mineral salts produced normal yield of mushroom. Some-
times the yield was even superior because better aeration was pro-
vided.
In the experiments of Rao and Block (1961), various waste ma-
terials such as garbage, sewage, sludge, sawdust, newsprints, straw,
and bagasse, mixed with chemicals, were composted. These were
found to be suitable media for growing mushroom.









PHILIPPIfE PHYTOPATHOLOGY


The present study was conducted in the Department of Plant
Pathology, College of Agriculture, University of the Philippines to
determine 1) the right combination of plant materials and inor-
ganic chemicals for the proper development of mushroom myce-
lium, and 2) the proper conditions necessary in making the spawn.


MATERIALS AND METHODS

Three kinds of plant materials were used either singly or in
combinations at 1:1 proportion on a 100-kg basis, namely:
Rice straw
Rice straw and banana leaves (1:1)
Rice straw and water lily (1:1)
Water lily
Banana leaves
Banana leaves and water lily (1:1)
Rice straw, banana leaves and water lily (1:1:1)
Four chemicals, each used at 3 rates of application, were added
to the plant materials during the composting process. These were:
Rate of application (kg/100 kg)
Chemicals
1 2 3
Ammonium sulfate 1.0 2.0 3.0
Urea 0.4 0.8 1.2
Calcium sulfate (gypsum) 2.0 3.0 4.0
Superphosphate 2.0 3.0 4.0

Composting. The organic material was placed in gallon jars
and soaked in water for 4 hours to make it pliable. Thereafter
the jars were transferred to an incubator of 50 C. Two days af-
ter, the desired rate of ammonium sulfate and about 70 ml of tap
water was added to each jar. After 4 days the mixture was turned
over for the first time; the desired rate of urea was added. After
the second turning, calcium sulfate or gypsum was added; and
after the third, superphosphate was added at the desired rates of
application. The process was accomplished within 20 days. Dur-
ing the process, color, odor, and texture of the test materials were
noted. Loss in weight after composting wa also recorded. .









AGARICUS BISPORUS


After the composting period, brewer's grains (previously
soaked and rinsed in water to remove the molasses) were added at
the rate of 1 to 2 parts by weight of the compost. This constituted
the spawn substrate which was either placed in petri dishes (Fig.
1) or in bottles. In one experiment, about 1 cm thick or gently
compacted compost was placed evenly in each dish. In another,
small-mouthed (2-cm diam.) bottles were used; the substrate was
placed inside the bottles little by little until they were sufficiently
filled. With the aid of a bamboo stick, about 15 cm long and 2 cm
in diameter, a bore at the center was made to facilitate the intro-
duction of the seeding material. In either case, the substrate was
autoclaved at 20 psi for 2 hours.
The spawn. Pure culture of A. bisporus grown on potato-
dextrose-yeast-extract agar for 1 month at 20 C was introduced
into each culture dish or bottle. The plated cultures were incu-
bated for 2 weeks and the colony diameter measured. The bottled
cultures were incubated until the substrate was densely covered
with mycelium. In both instances, the seeded substrate was incu-
bated at 20 C.
Experimental design. All experiments were conducted in a
randomized complete block design, with each trial replicated 3
times.


RESULTS AND DISCUSSION

Odor, color, texture, and loss in weight of the composting ma-
terials. After the addition of ammonium sulfate and urea to the
decomposing plant materials, strong ammonia odor which was very
distinct in water lily, was emitted. At this stage the compost
changed pH toward the acid side (pH 5.4). After the addition of
gypsum and superphosphate, the odor gradually changed to that
of bland-earth until composting was accomplished. At this stage
the pH reverted to neutral.
During the composting process, all the plant materials grad-
ually turned dark. No color difference was discernible to distin-
guish the addition of chemicals at any level.


41










PHILIPPINE PHYTOPATHOLOGY


Rice straw alone and in combination was pliable and easily
tore off after the composting process. Banana leaves and water
lily were rendered more pliable than the rice straw. The decom-
position at high temperature, coupled with microbial actions, must
have caused all these changes.
Loss in weight after composting (Table 1) was highest in rice
straw and water lily combination and was statistically significant
at chemical application rates 1 and 3. This was followed by rice
straw and banana leaves but without significant differences among
the 3 rates of chemical application. Loss in weight was low in water
lily but differences among the 3 rates of chemical application were
highly significant.

TABLE 1. Loss in weight of plant materials composted with chemicals used at
3 increasing rates of application a

1 2 3
Plant Material Mean
Application Rate M
Rice straw and banana leaves (1:1) 20.6 25.6 16.8 21.0
Rice straw and water lily (1:1) 31.5 36.5 37.0 35.0
Banana leaves and water lily (1:1) 20.6 20.2 20.5 20.4
Rice straw 31.3 33.3 35.2 33.3
Banana leaves 13.3 20.3 12.6 15.4
Water lily 19.6 7.6 13.0 13.4
Rice straw, banana leaves and water lily (1:1:1) 26.0 20.3 19.3 21.9
H SD ........... ............ 0.01= 6.26
0.05 = 5.21
a Ammonium sulfate, urea, gypsum, and superphosphate mixed with plant ma-
terials in succession during the composting process, each used at 3 application
rates (e.g. rate 1 was composed of 1, 0.4, 2.0, and 2.0 kg/100 kg wt of substrate)
of the above chemical, respectively, etc. Data are in grams, representing average
of three replicates at each indicated rate of application.

Mycelial growth of A. bisporus on the substrate. Typical
fungous growth on plated substrates are represented in figure 1:
Colony diameter was the criterion used to test differences among
various substrates. The widest colony diameter was recorded on
water lily. Poor growth was recorded on rice straw combined with
water lily. No significant differences were noted among plant ma-
terials but significant differences were obtained among the 3 rates
of chemicals (Table 2).









AGARICUS BISPORUS


Fig. 1. Plate cultures of Agaricus bisporus after 14 days on corn-
posted (1) rice straw and banana leaves, (2) water lily
alone, (3) banana leaves and water lily, (4) rice straw, ba-
nana leaves, and water lily.










PHILIPPINE PHYTOPATHOLOGY


TABLE 2. Colony diameter of A. bisporus in plated substrate composed of plant
materials to which was added in succession 4 chemicals at 3 rates of
application during the composting process a

Plant Material Application Rate b
Plant Material Mean
i 2 3
Rice straw and banana leaves (1:1) 2.86 1.55 1.73 1.71
Rice straw and water lily (1:1) 0.00 0.70 0.40 0.36
Banana leaves and water lily (1:1) 2.49 1.25 1.11 1.62
Rice straw 1.22 2.48 1.46 1.72
Banana leaves 1.53 2.72 2.93 2.39
Water lily 3.00 2.17 2.64 2.60
Rice straw, banana leaves, and
water lily (1:1:1) 1.42 1.15 2.70 1.76
H SD ...................... 0.01 = 0.87
0.05 = 0.72
a Data represent average of 3 replicates at each application rate. Chemicals
used were ammonium sulfate, urea, gypsum, and superphospate mixed in that
sequence with plant materials during the composting process.
b Three increasing rates were employed, e.g. at rate 1, ammonium sulfate was
used at 1, urea, at 0.4, gypsum and superphosphate each used as 2 kg. per 100 kg.
wt. of plant material, etc. Figures are in inches.


With the data on colony diameter and loss in weight of plant
materials after composting, it could be inferred that the :materials
with the least loss in weight provided the best growth for A. bis-
porus. Water lily and banana leaves, each used alone, were the ma-
terials which showed the least loss in weight after composting and
at which were produced the widest fungous colony diameter. The
bottled cultures yielded similar results as the plated cultures. Wa-
ter lily was invariably the first to become filled with mycelial
growth. In all the substrates, mycelial growth was characterized
by white thread-like filaments which were readily seen adhering to
the inner sides of the bottled cultures. It took more than 1 month
for a 1-liter bottle to become covered with mycelial growth.
Mushroom production. Preliminary studies on growing
Agaricus mushroom from plated and bottled spawn yielded normal
mushrooms (Figs. 2, 3 and 4). The bedding materials were synthetic
compost consisting of rice straw composted for 20 days in the same
manner as described above. The synthetic compost was contained
in flats 12" x 24" x 10". The seeded flats were placed in an air-con-









AGARICUS BISPORUS


Fig. 2. Pin-heads of A. bisporus on synthetic compost.




ditioned room with a temperature range of 14 to 20 C, and relative
humidity of 50 to 68%. The first harvest of mushroom was made
37 days after spawning. Yield was not yet comparable with the
average harvest of 2.5 lb per sq ft of bed space as reported from
other countries, but the mushrooms were undoubtedly of good
quality. More study on composting, care of the beds and control
of pests and diseases is necessary in order to obtain additional in-
formation concerning the cultural and environmental requirements
of this mushroom before it could be grown in commercial scale
under Philippine conditions.











PHILIPPINE PHYTOPATHOLOGY


Fig. 3. Cluster of mature A. bisporus.










AGARICUS BISPORUS


Fig. 4. Six developmental stages of A. bisporus (from right to left).











48 PHILIPPINE PHYTOPATHOLOGY

LITERATURE CITED

HEIN, I. 1930. Straw composts for mushroom culture. Mycologia 22: 39-42.
LAMBERT, E. B. 1929. Normal mushrooms from artificial manure. Science 70:
126-128.
RAO, S. S. and S. S. BLOCK. 1961. Experiments in small-scale composting. Dev-
elopments in Industrial Microbiology 3: 326-340.
RETTEW, C. R. and A. J. THOMPSON. 1948. Manual of mushroom culture.
Toughkenamon, Pa. 272 p.
SINDEN, J. W. 1938. Synthetic composts for mushroom culture. Pa. Agr. Exp.
Sta. Bull., 365, p. 1-27.
SINGER, R. 1961. Mushrooms and truffles. University Press, Great Britain. 272 p.
STOL-ElRT D. B. 1943. Preparation of synthetic composts for mushroom culture.
Plant Physiol. 18: 397414.
WAKSMAN, S. A. and C. A. RENEGER. 1934. Artificial manure for mushroom
production. Mycologia 26: 3845.
YODER, J. B. and J. W. SINDEN. 1954. Synthetic compost in America. Mush-
room Science 2: 133-139.













CULTIVATION OF AURICULARIA POLYTRICHA


JANE D. BORROMEO and DON R. REYNOLDS
Graduate Student and Instructor, respectively, Department of Plant Patho-
logy, U.P. College of Agriculture, College, Laguna.

ABSTRACT
The commercial method of cultivating Auricularia polytricha (Mont.) Sacc.
in Taiwan was tested under Philippine conditions. Fructifications were pro-
duced after 3 months. Suggestions are made for possible commercial pro-
duction of this species.


Auricularia polytricha (Mont.) Sacc., known in Tagalog region
as "taingang daga," has become a valuable ingredient in many
Chinese dishes. The fruit body has a convenient consistency for
marketing; it swells by becoming partly gelatinous when wet and
shrinks to a brittle sheet-like layer when dry.
Reinking (1921) was able to grow this fungus without diffi-
culty on some 40 species of wood along Molawin Creek in College,
Los Bafios, Laguna.
Recent collections in the Ocfemia Mycological and Phytopatho-
logical Herbarium in the U.P. College of Agriculture show that 7
out of 9 species in the genus are found in the Philippines. Of these
A. polytricha is widely distributed throughout the archipelago.
An article1 by Wu (1956) on the production methods used in
Taiwan is the only locally available literature on the commercial
cultivation of Auricularia. Singer (1961) in his comprehensive
treatment of mushroom cultivation only mentions that the fruit
bodies are not taken from inoculated logs but rather "wood nat-
urally infected with the desired mushroom."
Wu (1956) presented cultivation details and discussed the more
important factors involved in the process. He also mentioned the
wood species recommended as substrates, the corresponding num-
1 Translated by Mr. S.P.Y. Hsieh, IR.R.I. scholar from Taiwan.









PHILIPPINE PHYTOPATHOLOGY


ber of days necessary for the fruit bodies to emerge, and the quality
of the fructifications produced on each of them. Two Philippine
woods mentioned were Ficus retusa and Trema orientalis.
This preliminary study employing the Taiwan method of pro-
duction was conducted to determine the possibility of a large scale
production of'A. polytricha in the Philippines.

MATERIALS AND METHODS
The cultivation of A. polytricha involved 2 major processes:
1) the preparation of the spawn, and 2) actual log cultivation.
The spawn substrate was a moist mixture of sawdust and rice
bran at a 5:1 ratio. This mixture was placed in wide mouthed bot-
tles and autoclaved for 1 hour at 20-lb pressure. Into each bottle
was introduced mycelial fragments obtained from 2-week old cul-
tures on malt agar and incubated at room temperature for 1 month
until the bulk of the subtrate was almost completely covered with
mycelial growth.
For actual cultivation, recently cut limbs of Ficus retusa ("ba-
lete") and Trema orientalis ("Anabiong") were tested as wood
substrates. Two pieces of each species were used; each measured
about 3 ft long and 6 inches in diameter. Holes were bored through
the bark with the aid of a cork borer. They were about 1 cm in
diameter and in depth and separated from each other vertically
by 12 cm. Along the periphery of the limb the holes were about 9
cm apart. A pinch of spawn was introduced into each hole. This
was subsequently covered with a bark plug that snugly fitted the
hole. Bark plugs were obtained by means of a cork borer from
logs of the corresponding species. Holes of one piece of each spe-
cies were sealed with paraffin while those of the second piece were
left unsealed. The logs were then stacked in criss-cross fashion,
covered with several thickness of wet newsprint and kept under a
shade. Watering was done as often as necessary to keep the logs
moist.

RESULTS AND DISCUSSION
Fructifications were produced after 3 months a period that
was twice longer than that reported by Wu (1956). The fruit bo-









CULTIVATION OF AURICULARIA POLYTRICHA


dies emerged only from the holes that were sealed with paraffin.
Less than 50 fruit bodies were formed. The unsealed ones were
attacked by small insects and the bark plugs failed to remain in
place.
According to Mr. S.P.Y. Hsieh 2 who has successfully employed
this method in Taiwan, the low fruit-body yield was due to in-
sufficient humidity and aggravated by the insect problem.
It is conceivable that a more desirable method of cultivation
can be devised that would 1) eliminate the use of logs per se, 2)
not involve crude introduction of spawn into holes bored into wood,
3) take less time for fruiting, and 4) allow more growth and fruit-
ing control. Auricularia seems to develop naturally by growing
through the decaying wood tissue. At fruiting time in the natural
habitat, the hyphae may be seen to accumulate as a layei just un-
der the bark layer where the bodies will appear. The fructifications
develop through cracks or crevices in the bark. Similarly, fruit
body tissues develop at the mouth of opened spawn jars; the tis-
sues form as a layer and develop on the surface in monstrositous
form.
If some sort of substitute log could be devised which would
meet the conditions above, perhaps production on a commercial
scale would be possible. A desirable condition would be the util-
ization of widely available local materials. For example, bamboo
tubes filled with a suitable waste product which can support the
rapid growth of spawn, such as "ipil-ipil" (Leucaena glauca L.)
leaves and even sawdust, could serve as a substitute for the rotting
wood. The mycelium could develop inside bamboo sections
throughout the introduced substrate and fruit via holes or slits
cut in the bamboo surface.
If such a method will be feasible for Auricularia, then simi-
larly cultivated mushrooms such as the Shitakii mushroom [Len-
tinus edodes (Berk.) Sing.] can be produced in the same fashion.
The Philippines has the advantage over Taiwan of a continuous
warm season. With sophisticated cultivation, some of the multi-
million dollar mushroom market could be captured.
2 Personal communication.











52 PHILIPPINE PHYTOPATHOLOGY

LITERATURE CITED

REINKING, O. A. 1921. Philippine edible fungi. In W. H. Brown. Minor products
of the Philippine forest. Phil. Bur. For. Bull. 3, p. 97-147.
SINGER, R. 1961. Mushrooms and truffles. Interscience Publ., Inc., New York.
p. 171-172.
WU, C. 1956. Auricularia can be cultivated artificially. [In Chinse] Harvest 10: 22.













PHYTOPATHOLOGICAL NOTE


LEAF BLIGHT, PURPLE SPOT, AND CHLOROTIC STREAK
OF SUGARCANE IN NEGROS ISLAND, PHILIPPINES
J. R. RIVERA and I. B. CANO

Sugar Research Supervisor III and Plant Pathologist, respectively, Philippine
Sugar Institute, Bacolod City.
Published with the approval of Philippine Sugar Institute officials concerned
with technical papers.



From August to November, 1964, three unrecorded sugarcane
diseases were found at several places in Negros Occidental.
LEAF BLIGHT. This disease was commonly on POJ 3016, Phil.
54-42, B37-172, and H37-1933 in several localities. Diagnosis was
primarily based on symptomatology and identity of the associated
fungus, Leptosphaeria taiwanensis Yen et Chi. The symptoms re-
semble closely those described by Matsumoto (1952) and Hughes,
et al. (1964). Small narrow, elliptical or elongated yellowish spots,
visible on both leaf surfaces, first appear on immature leaves. These
spots soon become dotted with reddish tint and develop into elon-
gated, reddish-brown streaks which often coalesce into bands separ-
ated by narrow green portions of the leaf (Fig. 1). In the advanced
stage, the affected leaves die and dry. Severely infected plants ap-
pear reddish-brown at a distance. External hyphae are produced
on lesions at the nether surface of leaves; black fruiting bodies de-
velop along the margins of old lesions. We have observed this dis-
ease frequently associated with yellow spot and we like to think
that it had long existed in this island long before. Although its
distribution and economics has yet to be determined, it may soon
be widely distributed throughout the island especially in mill dis-
tricts where POJ 3016, B37-172, and H37-1933 are planted in com-
mercial scale. It may occur in epiphytotic proportions when sus-
ceptible new cane varieties are planted in large scale.










PHILIPPINE PHYTOPATHOLOGY


Fig. 1. Typical symptom of leaf blight on B37-172.
At extreme right is normal leaf.









LEAF BLIGHT, PURPLE SPOT, AHD CHLOROTIC STREAK


The control measures advocated by earlier investigators are
burning of trash after harvest and use of resistant varieties. In
Taiwan POJ 2883, POJ 2878, F.109, F.134, and Co.285 are listed as
very susceptible; NCo 310, F.108, F.107, and F.132 as slightly re-
sistant; and POJ 2725, and F.29.43 as highly resistant (Matsumoto,
1952; Hughes, et al. 1964).

PURPLE SPOT OR RED LEAF SPOT. The disease is characterized by
red or purplish-red spots on either surface of the leaf. Lesions are
circular, elliptical or irregular when 2 or more spots coalesce (Fig.
2). We found numerous dark brown perithecia on old lesions. Our
morphological and microscopic studies of the perithecia, asci, and
ascopores obtained from infected leaves revealed that they resem-
ble closely those of Dimeriella sacchari (B. de Haan) Hansford
(Matsumoto, 1952; Hughes, et al. 1964). In Victorias, La Carlota,
and La Granja Station, we found the disease affecting POJ 3016, NCo
310, Co 440, Phil 54-60, Phil 53-33, and Alunan. We also observed
the disease on some un-numbered seedlings of the 1963 series in
the La Granja Station. We believe that the disease may also be
present in sugarcane areas in Luzon. Its distribution and economic
importance is not yet well understood.

CHLOROTIC STREAK. Long yellowish to whitish streaks with ir-
regular margins characterize this disease (Fig. 3). This symptom
pattern is discernible on both leaf surfaces. In some infected stalks,
we observed reddened vascular bundles at the nodes.

The disease was first observed on H38-2915 and B43-62 at Ha-
cienda San Jose, La Castellana, Negros Occidental in Ocober, 1964
(Wismer and Rivera, 1964). It was common on canes growing
along the border of poorly drained fields. We observed it to be
more prevalent on ratoon crops. We attribute the primary causal
factor to a virus.










PHILIPPINE PHYTOPATHOLOGY


Fig. 2. Infected leaves of POJ 3016 showing diagnostic
character of red leaf spot or purple spot. At
extreme right is healthy leaf.










LEAF BLIGHT, PURPLE SPOT, AND CHLOROTIC STREAK


s~i i


Fig. 3. Characteristic symptom of chlorotic streak on
leaves of H38-2915.


i '

.









PHILIPPINE PHYTOPATHOLOGY


Several field surveys in La Castellana mill district showed 4
varieties affected by the disease. We tentatively classified their re-
action to chlorotic streak as follows:

H38-2915 .... Heavily infected (leaf streaking on 4 or more
B43-62
B43-62leaves)
Alunan .... .Moderately infected (leaf streaking on at
POJ 3016 least 12 leaves)


In Negros Island, the importance and distribution of this dis-
ease is yet to be determined but in some sugarcane-growing coun-
tries chlorotic streak is considered an important disease. We have
no doubt that this disease occurs in all low areas of other "hacien-
das" in the La Castellana district. If precautions are not observed
to forestall its spread, it may become a serious problem to sugar-
cane cultivation particularly in low areas.
Measures of control recommended by Martin et al. (1961) in-
clude selection of planting materials, hot-water treatment of seed
cane at 52 C for 20 min, prompt roguing of infected clones, use of
the more resistant varieties, and proper drainage.


LITERATURE CITED

HUGHES, C. G., E. V. ABBOTT and C. A. WISMER [ed.] 1964. Sugarcane diseases
of the world. Vol. 2. Elsevier Publ. Co., New York, 354 p.
MARTIN, J. P., E. V. ABBOTT and C. G. HUGHES [ed.] 1961. Sugarcane diseases
of the world. Vol. 1. Elsevier Publ. Co., Princeton, New York, 167 p.
MATSUMOTO, T. 1952. Monograph of sugarcane diseases in Taiwan. Chinese-
American Joint Commission on Rural Construction, Taipei, Taiwan. 61 p.
WISMER, C. A. and J. R. RIVERA. 1964. Notes on the occurrence of chlorotic
streak of sugarcane in Negros Island, Philippines. Phil. Sugar Inst. Quart.
10:155.














A PROPOSAL: COMPILATION OF HOST INDEX


To date there has been an adequate amount of work by re-
searchers in various areas of Philippine plant pathology to make
possible an assessment of what diseases occur here and what the
organisms involved are. But the only host index or any compila-
tion approaching an index is the Host Index for Economic Plants
by O. A. Reinking in 1918 (Phil. Agr. 8: 38-54). This was subse-
quently included in Dr. N. G. Teodoro's 1937 Enumeration of Phil-
ippine Fungi. This Enumeration appended a Host List.
Since 1937 there has been no new compilation of either fungi or
diseases, much less of hosts. It is proposed that The Philippine
Phytopathological Society undertake such a compilation. The list
should include articles or reports of departments and institutions
not yet published in any journal as well as those already published
in local and foreign periodicals which specifically cite Philippine
organisms.
The mechanics of coordination could easily be done through
the incumbent Chairman of the applicable subject matter commit-
tees and their members (Chairman for 1966-67: Bacteriology, M. O.
San Juan; Epidemiology and Meteorology, A. L. Eloja; Forest
Pathology, E. M. Mendoza; Mycology, Don R. Reynolds; Plant Vi-
rology, Ma. Salome del Rosario; Soil Microbiology, M. S. Celino).
Once sufficient lists in any one section have been compiled, then
publication could be contemplated by the Editorial Board of the
Society's Journal. This could be done in parts per issue or as a
separate special issue.


...... Ma. Salome del Rosario, President-Elect
Romulo G. Davide, Secretary
Don R. Reynolds, Mycology Committee











60 ,INE PHYTOPATHOLOGY





Rep of the Philippines
Department c Works and Communications
REAU OF POSTS
Plp tlo s -- Manila


SWORN STATEMENT
(Required by Act 2580)


The undersigned, ROMULO F. P. QUEMADO, business manager of the
PHILIPPINE PHYTOPATHOLOGY published semi-annually in English at
College, Laguna, after having duly sworn in accordance with law, circulation,
etc. which is required by Act 2580, as amended by Commonwealth Act
No. 201.


NAME
Editor: Agustin N. Pordesimo ........

Business Manager: Romulo F. P. Quemado
Owner: Philippine Phytopathology ......


Publisher: Philippine Phytopathology ....
Owner: Philippine Phytopathology .....
Printer: G. Rangel & Sons ............


ADDRESS
College of Agriculture
U.P., College, Laguna

Union Carbide, Philippines
Incorporated
P.O. Box 677, Manila
College, Laguna
College, Laguna
400 M. dela Fuente Street
Sampaloc, Manila


In case of publication other than daily, total number of printed and
circulated of the last issue dated July, 1965.
1. Sent to paid subscribers .............................. 400
2. Sent to other than paid subscribers ................... 100
Total .............................. 500

(SGD.) ROMULO F. P. QUEMADO
Business Manager

SSubscribed and sworn to before me this 28th day of April 1967, at Manila,
the affiant exhibiting his Residence Certificate No. A-4418881, issued at San
Juan, Rizal on April 14, 1967.


DOC. No. 161;
Page No. 34;
Book No. XH;
Series of 1967


MARIANO R. PEFIANO
Notary Public
Until December 31, 1967


NOTE: This form it exempt for the payment of documentary stamp tax.




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