VCE I' 196 NUMES1A
VOW~t 5 JANUARY ANDJNUBR 1
A c Papers Acceptid'~for Presentation at the Sixth Annual
MefrgOA o1-4.0 iPhlipp~e Phyt~opathologicai- Society, Bacolod
it Mu, 16-181969.................................
De Capcstyi Temperature Relation, and Oxidass Reaction of Phil-
ippinw. Fugil `Assciated with Deterioration, of Wood Products
IM'. A-.- Eiisbio ..................................... 20
161hi~ly e s;itoeur. General of Plant Parasitic Nematodes bn
f.- d40l1a'Rosa and R. G. Divide ................29
RbCarb~R oot-Knot- tPmetodes and Weeds in Cigar Filler To-
bacc Sndb l. by Soil Fumigation
: -C. '.iMaledamba, C. G. Goseco, and P. L. -Bagoyo .... 39
Reacirons-4 -D~f~font V9eptatble and Field 'Crops to Infection by
Ma Tqi .,,Tje Javanic.Davi
SRi T:.: ~ipledo nd R. G. Davide.....................45
Gnenhoun't~tbii Tet f Controiling Mung Bean Powdery MIldew by
-rn hrk.I in Soil
Fh u. Quebra ...............................52
An kj 000t6gatio of: the.Cause of 'the "Tapurok" Disease of Cooking
Bann in :Neujrot Ortintal
Eldon 1.. Zehr and R. G. Davide ...........55
"Official Organ of
S TI: l :PH lIPPINE PHYTOPATHOLOGrCAL SOCIETY
Ea'ter sra~o~iand -ais aaiV matter at the Manila Pout Office on 21 September 1970.
,1.. 4;~. :.:: ''
jhe, -P.P.S. Council: 1969-1970J.
President, R., F, P. QUENL4MO,,e AqogaS, Mandaluyong, Rizal
Retiring Presidelit, :A. V. PALO,, Bur au "of Plant Industry,,: Sa And es
Vice-President Elect R. G.' bAVIPE, UPCA,. College, Laguna
Secretary, G. G. DIVINAGRAqIA, UPCA, College,, Laguna
Treasurer, T. T. REYES, UPCA, College, Laguna
Editor-in-Chief, A. N. FORDESIMO, UPCA, 'College, Laguna
Newsletter Editor, G. G. DIVINACANCIA, UPCA, Co46ge, Laguna
Business Manager, C. A.--BANIQUED, Bureau of Plant Industry, 'San Andres, Ma
Auditor, F. L. NUQUE" Plaxit Protection ..Division, IRRI, College, Laguna
F. C. QUEBRAL, XJPCA, College, Laguna (Luzon).
J. R. RIVERA, Philippine Sugar Inst.' Bhcolod City aya
A. L. ELOJA, Bureau of Plant, Industry, Davao City (Mindanaoy
The P.P.S. Couneff 1970-1971
President, R.. G. DAVIDE, UPCA, College, Laguna
."Retirlng President,, R. F. P, QUEMADO, Rockgas,_ Mandalxiyong. Rizal,
VIce-President Elect, G. G.% DIVINAGRACIA, UPCA, College, Laguna
Secretary, C. T. RIVERA, Plant Protection Division, IRRI, College, Laguna
Treasurer, T. T. REYES,- UPCA,, College, Laguna
Editor-in-Chief, A. N. PORDESIMO, UPCA, College, 'Laguna
Newsletter Editor, R. G. DAVIDE, UPCA, College, Laguna
Business Manager, C. A. BANIQUED Bureau of Plant Industry, San Andres Manila
Auditor, F. L. NUQUE, Plant Pro;ection Division, IRRI, College, Laguna
F. C. QUEBRAL UPCA, College, Laguna (Luzon)
J. R. RIVERA; Philippine Sugar Inst., Bacolod. City (VisayAs)
'A. L. ELOJA! Bureau of, Plant Industry, Davao, City (Mindanao),
Canlubang Sugar Estate, Canlubang, Calamba, Laguna
Filipinas Pest Control & Filipinas Agricultural Trading, E. de los; Smtos Ave-, Ou
_FMC: Corpor4tion, Niagara Chemical Division, Middleport, Now York, U.S.A.
Tarlac Development Corporation, Hacienda Luisita, San Miguel, Tarlac
Uni6n'CarNde (Philippines) Inc., Makati, ftal
Velsibol Chemical Co., Makati, Rizal-
Victorias Milling Co., Inc., Victorias, Negros Occidental
AMFIL. Chernical Corp., Sikatuna Bldg., Makati, Rizal
Bayer Chemicals, Inc., 622 Shaw Blvd., Mandaluyong, Rizal
Central Azucarera de Baisj Bais, Negros Oriental
,EiGY, LTD.', Switzerland
Dole- jhilippines, Inc., Madrigal Bldg., Makati, Rizal
Official Organ of the Philippine Phytopathological Society
. N. PORDESIMO, Editor-in-Chief, Department of Plant Pathology
University of the Philippines, College, Laguna
. A. CALICA, Bureau of Plant Industry, San Andres, Manila
. P. GABRIEL, University of the Philippines, College, Laguna
I. E. LOPEZ, Philippine Sugar Institute, Quezon City
. L. MARTINEZ, Bureau of Plant Industry, Lipa City
iOLORES RAMIREZ, University of the Philippines, College, Laguna
business Manager, C. A. BANIQUED, Bureau of Plant Industry, San Andres, Manila
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foot the bill:
IJDO A ILAIrt J AJ AJ l AZiIk3 1.LAA A .4 AlAw A A A* Aw-
AT THE SIXTH ANNUAL MEETING OF THE PHILIPPINE
PHYTOPATHOLOGICAL SOCIETY, BACOLOD CITY
16-18 MAY 1969
(Arranged alphabetically according to first author's surname)
An improved rice-straw bed for Volvariella volvaceae. C. A. Baniqued
A. V. Arrienda Jose. A layer of rice hull about Y2 inch was uni-
ly spread over each layer of rice straw and was thoroughly watered.
top of each rice-hull layer, spawn of Volvariella volvacea (Bull. ex
Sing. was planted at the usual distance of 3 to 4 inches apart. This
nation of steps was followed until the mushroom bed reached the
it of 3 ft. For the control, newsprints were placed between layers
ice straw and were similarly seeded with the spawn. Watering was
on the 6th day after seeding and every other day thereafter to
the beds moist. The temperature in the experimental beds was
een 45 and 48 C while in the control beds, it was between 38 and
3. The first harvest of mushroom in the experimental beds was done
ays after seeding. Fructifications in the control beds were noticed
:he 13th day after seeding. No appreciable difference was noted on
size of the harvested mushroom but significant difference in yield
Chemical treatment of vegetable seeds for the control of damping-
- Nenita Capule-Baniqued and C. A. Baniqued. Six seed-treat-
t chemicals, viz., Ceresan, Vitigran Blue, D-198, Esso 406, Semesan,
Tillex were tested for their effectiveness in controlling damping-
>f pepper, tomato, carrot, onion, eggplant, and cabbage. The chemicals
:d widely in their effectiveness. The Semesan-treated pepper and egg-
t gave the highest emergence percentage. All the chemically-treated
i germinated better than the control. Cabbage seeds treated with
licals other than Esso 406 have poorer emergence than the untreated.
the fungicides gave protection against damping-off of pepper, egg-
.t and carrot. But Semesan was the most effective among the 6
Further study on the weed suscepts of Xanthomonas oryzae. R. H.
nga and F. M. Olivares, Jr. Twenty-six species of weeds represent-
20 genera in the families Pontedriaceae, Euphorbiaceae, Amaranthaceae.
were not inrecrea Dy Aanrnumonas oryzae (uyeaa at ismyama) iWow
by artificial inoculation at the Maligaya Rice Research and Training C
ter of the Philippines. Only BPI-76-1 (MS) and IR8-288-3, the suscepti
indicators, became infected after inoculation. Based on these results,
the test weeds are considered non-hosts of X. oryzae and that they F
no problem as sources of inoculum in the field.
Some effects of nutrition, temperature, and light on pycnidial I
duction of Phomopsis vexans in agar culture. G. G. Divinagracia.
The fungus, Phomopsis vexans (Sacc. & Syd) Harter, was grown on 13
ferent agar media at 4 different temperatures, and under different li
conditions. It produced many pycnidia on oatmeal, rice, and wheat a
media. On oatmeal agar, the pycnidia were smaller and ,solitary at-
oatmeal content but were larger and tended to aggregate at high oatn
content. Also, it needed light for abundant pycnidial production. It
peared that the region close to the hyphal tip was the most sensitive
the stimulatory effect of light. Overall growth and pycnidial product
was favored at 30 C. Mycelial growth was inhibited at 35 C but py,
dial production was abundant where mycelial growth was dense. The fun
should be grown in 4-7% oatmeal agar at 30 C with adequate light
produce a large amount of inoculum.
Effect of temperature on the viability of Xanthomonas oryzae.
Sunetra Eamchit and S. H .Ou. Naturally-infected rice leaves with I
dressing lesions of bacterial blight, artificially-inoculated rice seeds, ;
X. oryzae in agar-slant cultures, in water suspension, and on paper d
were subjected to different temperatures in several series of experime
When inoculated seeds of 5 rice varieties were kept at 4, C (c
storage), 100% survival (based on number of seeds yielding bacterial o
nies) was obtained after 7 months and 95% after 9 months on var. Taichi
(Native) 1. At 22-24 C (air-conditioned room temperature), the percent
of survival began to decline after about 21 days, reaching 50% in ab
51 days and completely lost viability in 57 days. At 21-33. C (ordin
room temperature), the percentage of survival began to drop after 6 d;
completely losing viability in 24 days. On JC-70, the shortest viability:
100% survival was obtained after about 30 days, 45% after 110 days
4 C; but at 21-33 C, the survival was 55/2 after 5 days and none al
13 days. When studied at a narrower range of higher temperatures;
bacterium on the inoculated unhulled grains lost completely its viabi
in 12 to 24 days at 35 and 34 C, about 30-36 days at 32 and 28 C,
48 days at 22-24 C.
The bacterium in the naturally-infected leaves lost its viability in
30, and 33 days at 22-24, 28, and 32 C, respectively, and in 24 days
34 and 86 C. In water suspension, it died in 6 days at 36 C, 30 and
:ar-slaht culture, it. died'in 6 days at 36 C, 21 days at 34 C, 63 days
C but was -still alive after 120 days at 22-24 -arid 28 C.. The rela-
short life of, X. -oryzae at higher temperatures suggests that its dis-
ation by seed in the tropics is not of great concern.
ongevity of Xanthomonas oryzae phage at different temperatures. -
ra Eamchit and S. H. Ou. A strain of X. oryzae (B-15-37) and a
iophage (BP-x) were suspended in sterile tap water and incubated
iperatures of 24, 28, 32, 34, and 36 C. Longevity of the bacterium was
by transferring to Wakimoto's agar. Also, longevity of the phage
tested against a sensitive isolate of bacterium B-15, at 3-day interval.
'he experiment showed that the bacterium is killed in 6, 27, 30, 33,
7 days at 36, 34, 32, 28, and 24 C, respectively The phage becomes
ie in 45 days at 36 C and more than 77 days at all other tempera-
In many ecological studies on the bacterial blight of rice, the
ice of phage has often been used to indicate the presence of the
ium both qualitatively and quantitatively. The present experiment
to suggest that the presence of phage may not indicate the presence
Bacterium, particularly when the bacterial population is declining;
y be useful only when the bacterial population is increasing in the
ling of a crop season.
anthomonas oryzae strains resistant to antibiotics. Sunetra Eamchit,
Ou, and 0. R. Exconde. Five antibiotics were used to isolate anti-
resistant mutants in several strains of Xanthomonas oryzae... Colonies
appeared on agar cultures with low concentration of each antibiotic
gradually transferred to the next higher concentration starting from
i. Mutants resistant to 2000 ppm streptomycin were obtained' from
Kd and B-29, and to 20 ppm streptomycin, from B-23; to 200' ppm
Ilin, from Kd, to 100 ppm penicillin from B-29 and B-15, and to
m penicillin, from B-6; to 100 ppm dicrysticin, from a Kd streptomy-
istant mutant; to 20 ppm chloromycetin, from B-29 and B-72; and
ppm aureomycin, from B-29, to 10 ppm aureomycin, from Kd and
olates Kd and B-29 seemed to be more mutable and adapted to very
concentrations' of antibiotic, particularly to streptomycin. The strep-
in-resistant mutants were also found to be resistant to dicrysticin, ex-
ig a cross-resistant phenomenon.
among the 5 antibiotics, streptomycin seemed to be the easiest for the
ium to get adapted while aureomycin seemed the most difficult. Strain
originally tolerated 100 ppm penicillin but could not get adapted to
than 200 ppm. All the test isolates tolerated 10 ppm chloron ycetin
o mutant that can grow at a concentration of more than 20 ppm was
Suscept range of, and sugarcane varieties resistant to Xanthomonas ru
lineans. R. V. Estioko and T. T. Reyes. Xanthomonas rubrilineans (
et al.) Starr and Burkh., the causal bacterium of sugarcane red stripe,
fected 11 of the 17 artificially-inoculated grass species. These inclu
Arundo donax var. versicolor (Mill.) Stokes, Cvp'erus rotlndus IL.. Imel
cylindrica L., Paspalum conjugatum Berg., Pennisetum purh7iem Schum
Rottboella exaltata E. F., Saccharum sp. (Malaybalay), S. slo,.n,',"m
Sorghum vulgare Pers., S. halepense (L.) Pers., and Zea manw L. Grienhe
test showed that all of the 20 commercial and breeding stock vaicities i
were susceptible to X. rubrilineans.
Degradation of lignin in wood by white-rot and brown-rot finmi.
M. A. Eusebio. Determination of lignin content of alcohol-benzene-tre;
apitong (Dipterocarpus grandiflorus Blanco) and yakal (Shoren a,:vlo.sa Fo,
before and after exposure to white-rot and brown-rot fungi g.ve informal
on the relationship between lignin degradation and type of rot prod
The white-rot fungi, Fomes lividus (Kalchbr.) Sacc., Po7v-iorus maxi,
(Mont.) Overh., and Pleurotus sajor-caju (Fr.) Sing., caused more losses
lignin than the brown-rot fungi, Polyporus rubidus erlk.. Len:itefs sOl
ruginea Berk., and L., striata (Swartz ex Fr.) Fries. High lignin content
peared to increase the decay-resistance of yakal to brown rot but not
white rot. It seemed that lignin-destroying enzymes of the white-rot ft
were able to penetrate and act within the cell wall where liznin
abundant. Small losses in lignin content were associated with the de
action of the brown-rot fungi. Whether these losses represented lignin u
nation by the brown-rot fungi or changes in lignin solubility is still
Assessment of rice yield loss due to bacterial blight. O. R. Exco
and K. Phanomsawarn. Assessment of yield loss due to bacterial
blight in BPI-76, PB-76-13, and C4-143 was conducted at the lowland
field of the Central Experiment Station, College, Laguna. Yield losses
3 disease intensities and 3 stages of inoculation were determined. TI
were highly significant losses in yield of BPI-76 and PB-76-13 at the
disease intensities compared to the control. The losses in yield of BP
at disease intensities 1, 2, and 3 were 115, 88, and 155 g per 1.35 m2
22, 17, and 29%, respectively. For PB-76-13, the losses in yield were 56
and 83 g per 1.35 m2 or 11, 2, and 16%, respectively. No significant
in yield was recorded for C4-143. In all 3 varieties, no significant ir
action was obtained between the stages of inoculation and disease in
Pathogenicity patterns of Xanthomonas translucens f. sp. oryzae
G. Franck and S. H. Ou. From preliminary inoculation experiment!
rice varieties representing resistant, intermediate, and susceptible react:
were inoculated with 25 selected isolates to study the nathorenicitv beha'
rT*TmTwT V -v
ie bacterium. Results showed various patterns of pathogenicity that
be conveniently categorized into 4 major types: Type I, represented
isolate S-78, showed high virulence and incited very distinct pathologic
ion among the resistant, moderate, and susceptible varieties. Type II,
sented by isolate S-93, was intermediate in virulence. Type III, repre-
d by isolate S-95, was very low in virulence. Type IV, represented
-94, did not incite any difference in pathologic reaction among the
ential varieties. No distinct pathogenic races have been observed.
e pathogenicity patterns were very similar to those of the rice blight
changess in bacteriophages of Xanthomonas translucens f. sp. oryzae. -
ranck and S. H. Ou. Goto in 1964 reported 6 phages (Sp 1 to
) of the rice-streak bacterium and 16 lysotypes of the 84 isolates
. These phages and bacterial isolates stored in deep freezer were
ed as to their interaction along with the new isol'ates. Several
'-plaque reisolations were made from each of the original phages.
as found that these single-plaque reisolates differ from the original
:s in reaction to the host bacterial isolates, e.g., a reisolate from
SSp 1, designated as Sp 1-1, lysed the bacterial isolates S-20, S-24,
which were not lysed by the original Sp 1, while bacterial isolates
and S-81 were lysed by Sp 1 but not by Sp 1-1. New type of phagis
appeared. All the original 6 phages, except Sp 3, produce such .
phages. Nine such new phages have been found and they.- are
nated as Sp 1-1, Sp 1-2, Sp 2-1, Sp 2-2, Sp 2-3, Sp 4-1, Sp 5-1, Sp 6-1, and
-2. Besides those produced by the old phages, many new phage
ions were made and a number of them were classified as new, based
ie sensitivity of the bacterial isolates. Based upon 20 host bacterial
es, 18 new phages have been characterized and are designated as Sp
Sp 24. Altogether, 33 phages of the rice-streak bacterium are now
n in the Philippines. The ability of these 33 phages to lyse the
:st bacterial isolates varied from 1 to 14, mostly 5 to 8. The 20
rial isolates sensitive to the 33 phages vary from 2 to 28, mostly
) 15. At present, at least 3 bacterial isolates, S-74, S-73, and S-77
required to detect the presence of all phages.
Rice varieties resistant to bacterial leaf streak. G. Franck, S. H. Ou,
. Nuque, and S. D. Merca. A total of 1002 rice varieties have
screened for resistance to bacterial streak by spraying bacterial sus-
on of either virulent strain S-101 or S-103. Disease reaction was
fied by a 10-unit scale based on the length of lesions which was
I to be a more reliable criterion than the number of lesions: 0,
1 to 9, the 0 and lower units indicate resistance and higher units,
ptible. Of the 1002 varieties tested, none was rated 0; there were
8; and 6 in 9. The varieties classified in scales 1 and 2 tan be a
in breeding for bacterial-streak resistance. As a group, wild rice sped
and strains were resistant to the disease. Five of the 6 varieties 'in sc
1 were wild rice.
Ability of Nephotettix apicalis to transmit the rice tungro virus.
K. C. Ling. The transmission of tungro and similar diseases such
panyakit merah in Malaysia, yellow orange leaf in Thailand, and leaf
lowing in India by Nephotettix impicticeps Ishihara has ,been experiment
ly demonstrated by researchers in India, Indonesia, Malaysia, Pakisl
Philippines, and Thailand. But its transmission by N. apicalis (Motschul
is still unsettled. Because of the difficulties in distinguishing morp
logically N. apicalis from N. impicticeps, a toxonomic-transmission sti
was made by examining the morphological features of male insects
dividually after transmission tests, identifying the species 'according
taxon6mic keys, and comparing the transmitting ability of these 2 spec
Based -on the insects examined, the morphological characteristics
N. apicalis are a vertex with a submarginal black band, tegminal sI
which are often present and confluent along the claval suture, and
aedeagus with a total of 10 to 23 (mostly 14 to 17) teeth. N. impictic
is characterized by a vertex without a submarginal black band, tegmi
spots which are either present or absent, and if present, are not confli
'along the claval suture, and an aedeagus with a total of 4 to 10 (mc
7 to 8) teeth.
Sixty out of 821 insects from 11 samples collected from different Ic
ities in the Philippines were able to transmit the tungro virus after
quisition feeding of 4 to 5 days. The percentage of active transmit
varied from 0 to 27%. But the highest percentage obtained was 4
when the insects were tested daily for 4 consecutive days after acquisil
feeding for 5 days and after being provided with daily reacquisition f
ing. The average percentages of active transmitters were 17.4 and
for N. apicalis and N. impicticeps, respectively. These increased to
and 83.7 when supplemented with daily reacquisition feeding. The
centage of infective insects of both species decreased gradually -with t
following the termination, of acquisition. feeding. The longest. reteni
periods obtained were 3 and 4 days for .N,, apicalis and N. impiict
respectively. Both species were able to, become reinfective after the sec
acquisition feeding. The average .infectivity retention periods were,
and 1.38 days for N. apicalis and N. impicticeps, respectively. With d
reacquisition feeding, the average number of disease-transmitting days rw
in 4. consecutive days was 1.28 for, N. apicalis and 2.70 for N. impictic
The reasons for negative transmission iby N. apicalis in the literal
iciency of acquisition feeding period. But N. apicalis is a less effi-
trarismitter than N. impicticeps although the virus-vector interaction
e fdirer :does not differ fundamentally from that of the latter.
preliminary studies on the resistance of rice varieties to tungro and
vector, Nephotettix impicticeps. K. C. Ling. Virus disease re-
ce in plants and insect resistance in cultivated crops are interrelated.
viruses vectored by insects, available informations indicate that re-
:e to the virus may actually be associated with resistance to, the
vector. Under natural conditions, it is often difficult to specify
er low virus disease incidence in a particular variety: is, due to its
nce to the virus or to its resistance to the insect vector. The rice
y Pankhari 203 is not only resistant to the tungro virus but also
: leafhopper vector, Nephotettix impicticeps Ishihara, while the variety
ung (Native) 1 is susceptible to either the virus or the vector. The
i study was aimed to determine whether a rice variety' resistant to
ingro virus is also resistant to N. impicticeps, and vice versa.
bout 565 to 682 seedlings of each of the 4 rice varieties Taichung
ve) 1, IR 8, Kai Lianh Hsung Ting, and Pankhari 203 were inocu-
with the tungro virus by the mass screening method. The average
Itage of seedlings showing typical tungro symptoms was 94 for Taichung
ve) 1, 83.7 for IR 8, 19.4 for Kai Lianh Hsung Ting, and 5.5 for
ari 203. The differences among varieties were statistically significant.
basedd on the present arbitrary grouping system, the first 2 varieties
classified as susceptible while the last .2 as resistant, to the tungro
'he life span of N. impicticeps was determined by confining adult
individually on seedlings in test tubes. In several tests, a total of
insects was confined on seedlings of. each variety. The average life
of the insects was 21.9, 20,3, 4.4, and 3.4 days when they fed on
ung, (Native) 1, Kai Lianh Hsung Ting, IR 8, and Pankhari 203,
tively. r The average life span of insects that fed on the first 2 varie-
vas significantly longer than that on the. last 2 varieties.
excluding intermediate types,' there are only' 4 theoretical 'combinatid6is
istarice to the virus and to the Vector, viz., 1) resistant' to the vector
esistant to the virus, 2) resistant to the vector but susceptible to the
3) 'susteptible to the vector but 'resistant to the virus, and 4) sus-
le to the vector and susceptible to the virhs. Pankhari 203, IR 8,
Lianh 'Hsung Ting, and Taichung (Native) '1, respectivelyy, could
as examples for. these 4 ~dmbinations.' -Consequently, resistance to
ungro virus may 'not always' be correlated' to resistance to the insect
Causal agent-vector interaction of rice grassy stunt. K. C. Li
Soon Hyung Lee, and V. M. Aguiero. The causal agent of rice gra
stunt is transmitted by Nilaparvata lugens (Stal). A daily serial tra
mission was conducted to determine the interaction of the causal age
and the vector. The results indicated that there were no consistent <
ferences in the percentage of active transmitters between male and fer
adults, between insects of dark brown and light brown in color, or
tween macropterous (long winged) and brachypterous (with short or
breviated wings) forms. The macropterous insects were suspected to
more capable of spreading the disease than the brachypterous. The I
centage of active transmitters of the insect field population varied am<
localities; it was often within the range of 20 to 40%. In extreme ca
it, was lower than 3% and higher than 50%. The insects were not a
to transmit the disease immediately after the termination of 1 or 2 d
of acquisition feeding. The causal agent had a definite incubation per
of 5 to 28 days (average 10.6 days) in the vector. A majority of the
fective insect often retained their infectivity until death, while a few
trained their infectivity for a few days and became non-infective for
rest of their lives. The longest retention period was 40 days after acqt
tion feeding or 30 days after the insect became infective. The insi
acquired the causal agent at the nymph stage and became infective
the adult stage after 2 moltings without access to any diseased plant. I
indicated that the retention of infectivity was not altered by insect molti
The transmission pattern could be classified as of the intermittent rat
than of the consecutive type because more than 60% of the infective
sects failed to transmit the disease consecutively at either hourly or d
intervals. The average number of disease-transmitting days was 0.81 dui
the period from the time the insect became infective until its death.
infective insect transmitted the disease in about 80% of the total num
of days during that period. No infective nymphs so far had been obtai
from eggs of infective females, hence, there is still no available evide
to demonstrate the possible transovarial passage of the causal agent.
shortest itioculation feeding period was 9 min. Within 24 hr, the lor
the inoculation feeding period, the higher was the percentage of posi
transmission. Although the vectors often confined themselves to the b;
portion of rice plants, positive transmission was obtained by confirm
the viruliferous insects on the leaf blade of rice seedlings. Based on tl
results, it can be concluded that the causal agent of the disease per,
in the vector. Evidence obtained is not sufficient to demonstrate whei
it is of the circulative or of the propagative type.
Soil fumigation of seedbeds for nematode control in relation to y
of filler and wrapper tobacco. C. P. Madamba, C. G. Goseco, H. Pasi
and P. L. Bagoyo. Nematode-free seedlings of wrapper tobacco plar
Nos. 1 & 2
galls of Meloidogyne incognita Chitwood. Nonfumigated fields transplanted
with nematode-free seedlings yielded 4% more cured leaf weight thar
when the same fields were transplanted with nematode-infected seedlings
The previously fumigated fields transplanted with nematode-free seedling
gave 26.2% more yield, while the same treated field planted with nematode
infected seedlings gave only 18% yield increase.
Regardless of whether the seedlings were nematode-free or not, fumi
gated fields had markedly less root-knot nematode larvae, low nematode
population, and less plant mortality due to wilt. Likewise, more lea
yield was obtained in the fumigated field.
In the case of open-grown filler tobacco, more harvestable leaves dev
eloped from nematode-free seedlings planted in non-fumigated field.
A bark disorder of Sziwuikom mandarin in the Philippines. A. L
Martinez. The bark disorder of trees of Sziwuikom mandarin on Cala
mandarin rootstock characterized by scaling and cracking or splitting o
the bark on the trunk immediately above the bud-union and on the limbs
branches and twigs was experimentally demonstrated to be caused b
exocortis virus. A majority of the healthy seedlings and/or budlings o
Sziwuikom that were inoculated from field trees of Sziwuikom, affected
with the severe bark disorder, developed on the main stem and twig
longitudinal cracks and yellow blotches within 20 to 32 months. Also
the inoculated budlings of 'Etrog' citron 60-13 and 861 on Calamandari:
rootstock developed longitudinal cracks or sunken lesions and yellow blotches
on the bark of the main stem, leaf and stem epinasty, corky lesions ol
the midribs, and necrosis of the petiole base, which are typical of exocorti
symptoms on this indicator variety. It was demonstrated that the ser
sitivity of Sziwuikom mandarin to exocortis infection was unaffected b
the presence of tristeza, seedling-yellows and/or greening (leaf-mottle-ye
lows) in the sources of inocula. Although exocortis symptoms on Sziwuikoi
mandarin either as a seedling or budling developed slowly, this variety
can be used as an indicator for exocortis virus in the absence or unavai
ability of better indicators such as 'Etrog' citron. Nevertheless, becau
of the long incubation period in Sziwuikom, the preferred short-time ind
cator for exocortis is 'Etrog' citron.
Failure to transmit citrus greening (leaf-mottle-yellows) virus through
seed and soil. A. L. Martinez, D. M. Nora, A. L. Armedilla, P. I
Lacdao, and F. C. Jaquias. Several attempts to transmit greening (lea
mottle-yellows) virus through the seed and through the soil yielded negatil
results. (Failure to transmit this virus either through the seed or so
strongly suggests that its dissemination or spread is mainly through tl
use of infected nursery stocks and by the psyllid vector, Diaphorina cit
Presence of greening (leaf-mottle-yellows) virus in Oriental Mindoro. -
A. L. Martinez, D. M. Nora, and P. D. Lacdao. Recent indexing tesi
have demonstrated the presence of greening (leaf-mottle-yellows) virus i
some citrus orchards in Oriental Mindoro. The virus was experimental
obtained from trees of Ladu and Sziwuikom mandarin that exhibited typic
symptoms of yellowing and mottling of the leaves similar o that induce
on greening-infected trees in the provinces of Batangas, L una, and. Qui
zon. The virus was not encountered in both chlorotic and symptomless
trees of these 2 mandarin varieties and in other citrus species in psom
orchards. It appeared that greening is not widely distributed as yet i
certain orchards visited. The presence of greening in some citrus plan
ings of Oriental Mindoro must be considered in the selection of viruM
free budwood sources for propagation as well as in the prompt control c
the psyllid vector, Diaphorina citri Kuway, if it exists in that area.
The effect of cadang-cadang infection on carbohydrates of Cocos nuc
fera. D. E. Mendoza, Ma. Salome del Rosarib, and A. D. Bustrillos. -
Freshly collected coconut leaflets of comparable ages representing different
stages of cadang-cadang infection, yellowing (not cadang-cadang in nature:
and apparently healthy plants were analyzed separately for their tota
sugars, starch, and crude protein content. Leaflets with early (CCE), mile
(CCM), and severe (CCS) cadang-cadang contained greater amounts of tota
sugars, reducing sugars, and sucrose than healthy (H) and yellowing leal
lets. The H leaflets and those with mild yellowing (MY), and with sever
yellowing (SY) had close mean values for total sugars, reducing sugan
and sucrose content. The highest starch accumulation wasg obtained from
leaflets with SY, CCE, CCM, and MY which had comparable amounts o
starch that were higher than those with CCS, early yellowing (EY), ane
healthy leaflets. Crude protein content was highest in leaflets with CC]
and CCM but the amount of crude protein in those with CCM, CCE
CCS, and SY was statistically comparable with each other. Also, those wit]
CCS, MY, and SY had comparable crude-protein contents but were in lesse
Variation in pathogenicity among single hyphal-tip isolates of Pyricu
laria oryzae. S. H. Ou, K. C. Ling, F. L. Nuque, T. T. Ebron, Jr., an
J. M. Bandong. Earlier studies have shown that many pathogenic race
may be differentiated among conidia produced in a single lesion and monc
conidial cultures. Experiments were further made to study the variabilir
among single hyphal-tip isolates from germinating conidia. Single hypha
tip originating from each apical and basal cell of the conidium was oh
taihed from 2 germinating conidia of isolate 1-42. The resulting hyphal
tip cultures were designated as A-a, A-b, B-a, and B-b' (where big letter
represent cbnidia, a for apical cell, and b for basal cell). Fifteen to 21
single-hyphal tips were further obtained from the original 2, hyphal ip
-9 -nUl 1-^vrf;nm T"^a _n*;? rf -1,h -f thf 1 K f^ Or lIMI^- 9*..-
A ncr A r(rc
inoculated to the Philippine and International differential varieties. By
the latter differentials, the 20 single-hyphal-tip isolates of A-a were separated
into 3 races; the 17 of A-b isolates into 7 races; 17 of B-a into 2 races;
and 15 of B-b into 5 aces. By the Philippine differentials;, the 20 single.
byphal-tip isolates of A-a were separated into 7 races; 17 of A-b into '
races; 17 of B5a into 8 face; 'and 15 of B-b into 8 races. This further
indicated that the fungus produces new races not only from single conidium
which was 3-celled but also from single-hyphal tip originating from either
the apical or basal cell of a conidium. A total of 9 international race
groups and 19 Philippine races evolved from the two conidia of isolate
1-42. Among the races, ID-9 (International) and and P-23 (Philippine,
which are the original races of 1-42 dominated the population.
Results of the international cooperative blast nursery tests in the Phil
ippines from 1965 to 1968. S. H. Ou, F. L. Nuque, and T. T. Ebron
Jr. The International Uniform Blast Nurseries (IBN) were established ir
8 stations in the Philippines. These are located in San Mateo, Isabels
(Northern Luzon), Mufioz, Nueva Ecija (Central Luzon), IRRI at Lo!
Bafios, Laguna (Southern Luzon), Pili, Camarines Sur (Southeastern Luzon)
Sta. Barbara, Iloilo (Western Visayas), Musuan, Bukidnon (Central Min
danao), Midsayap, Cotabato (Southern Mindanao), and Palo, Leyte del Nort<
(Eastern Visayas). Two sets of seeds were tested. The first set (IBN'
consisted of 258 varieties used as differentials in Japan, USA, and Taiwan
and as commercial varieties in 18 other countries. The second sei
(BRWCV), consisting 321 varieties screened from more than 10,000 varie
ties were tested from .1966 to date. The cumulative test results of th(
IBN Group: I, showed great differences in reaction; some varieties wern
resistant, susceptible or intermediate, irrespective of locations and time o:
testing. In 51 tests; 26 varieties exhibited a high degree of resistance vt
rice blast in all regions.. The varieties Tetep, Kam Bau Ngan, Pah Ieuac
29-8-11, and' C46-15 demonstrated a broad spectrum of resistance in all Ie
gions. These varieties may be used in breeding for resistance to rice blas
in the Philippines.
Of the 11 Philippine varieties, Milbuen 5 (3) appeared to be more re
sistant than others in 37 of the 51 tests. It was susceptible in only 4 test
and moderately resistant "in the remaining tests.' There were difference
in reaction :among the varieties in different regions, e.g., Bengawan, FI
121 :and BPI 76 were 'resistant in the Bicol Region but susceptible in Lo
Bafios, indicating that) the patterns of races differed in these 2 locations
There were also differences in reaction of the same varieties at' different
seasons, e .g-FB 121 exhibited intermediate, susceptible and resistant re
actions in Isabela, suggesting differences in prevailing races at different
Nos. 1 & 21
Of the 321 varieties (BRWCV) in 31 tests, 19 showed high degree
resistance to rice blast in the different regions. The varieties that show
the same degree of resistance were S20VKW, Amvatsari, and 268b/F
22/31; these were resistant in 30 of the 31 tests and moderately resistE
in only one test. Varieties Ca 902/b/22 and Chuvanna Modan were
sistant in 29 of the 31 tests but moderately resistant in the other 2 tes
these varieties may, likewise, be used in breeding for resistance to r
New pathogenic races of Pyricularia oryzae in the Philippines.
S. H. Ou, F. L. Nuque, T. T. Ebron, Jr., and Md. Quamaruzzaman.
Studies on the pathogenic races of the blast fungus have been pursued
obtain more information relevant to breeding for disease-resistant var
ties. Two sets of differential varieties (Philippine and International) wo
employed to distinguish races. From 1965 to 1967, 88 pathogenic rac
based on the 2 sets of differentials, were identified. In 1968, 30 ni
races, based on the pathologic reactions of the Philippine differentia
were distinguished. Among the newly identified races, P106 is the m,
frequently isolated, followed by P105, P92, P90, Pill, and P112. Rai
P89, P92, and P103 were most virulent. Race P89 was pathogenic to t
Philippine differential varieties, except Wagwag, which was resistant. RE
P96 appeared to be the least virulent; it incited susceptible reaction
only 3 Philippine differential varieties, viz., Khao Tah Haeng-17, Ramin
Str. 3, and Wagwag. Based on the international differentials, 11 n1
pathogenic races were identified. Of these, IA-67 proved to be commc
followed by IA-97, IA-96, etc. The most virulent races were IA-67 al
IA-97 whereas IF-2, IF-3, and IA-124 were the least virulent. Race IA-
infected 6 differential varieties; it did not infect Zenith and CI-8970 (
Race IA-97 was pathogenic to all except Zenith and NP-125. IF-2 -
pathogenic only to Kanto 51 and CI-8970(S) whereas IF-3 infected or
Kanto 51 and CI-1561. There are now 118 pathogenic races and 67 ra
groups in the Philippines, based on the pathologic relations of the Ph
ippine and International varieties.
Variation in pathogenicity of single-colony subcultures of Xanthomor
oryzae. S. H. Ou, M. K. Palomar, and F. L. Nuque. Two single-colo
isolates of X. oryzae, B-15 (highly virulent) and B-23 (less virulent), w(
selected to study the variation in pathogenicity among their daughter co
nies. Pathogenicity was tested on one resistant (Zenith) and one susceptil
(JC-70) rice variety at seedling stage. One hundred to 120 single-colo
subcultures were isolated for each test and inoculated on the indicate
plants by needle pricking. The degree of pathogenicity was reckoned
terms of pathologic reaction of the indicator plants. This i~a measure
by a scale of 10 units (0, and 1 to 9); 0 for no lesion, 1-3 I
highly to moderately resistant, 4-6 for intermediate, and 7-9 for susceptil
action of 3 on Zenith and 8 on JC-70 whereas isolate B-23 produced a 2-3
-eaction on Zenith and 5 on JC-70.
From the subcultures of the original B-15, a more virulent strain,
B-15-37, was able to incite a reaction of 5 on Zenith and 9 on JC-70;
rom the subcultures of B-15-37, a still more virulent strain B-15-37-109
was able to incite a reaction of 8 on Zenith. Among the less virulent
subcultures of the original B-15, a strain B-15-1 caused a 0-reaction on
Zenith and 4 on JC-70. From the subcultures of the original B-23, a more
virulent strain B-23-13 caused a recation of 4 on Zenith and 9 on JC-70;
a less virulent strain B-23-56 caused a 0-reaction on Zenith and 1 on
The experiment demonstrated the pathogenic variability of the bac-
:erium. If the process of selection continues, it is possible to find very
weak pathogenic subcultures from the originally virulent strain that will
iot infect even the most susceptible variety; and very virulent strain from
:he originally less virulent strain that can infect the most resistant varie-
:ies. Perhaps, this phenomenon can explain the presence in nature of
nany strains with variable degrees of pathogenicity. It seems that a
single-colony isolate does not necessarily represent the degree of pathogeni-
:ity of the bacterium in infected specimens.
Pathologic reactions of some solanaceous plants to the root-knot nema-
tode. A. V. Palo and R. H. Calinga. The pathologic reactions of
some varieties, hybrids, and lines of tobacco, tomato, eggplant, and pepper
:o the root-knot nematode, Meloidogyne incognita Chitwood, were tested.
The experiments were carried out in 6-inch clay pots with a decontaminated
5:1 loam-sand mixture. A total of 47 entries of tobacco, 13 of tomato, 7
)f eggplant, and 6 of sweet pepper were tested by artificially infesting
he soil with larval suspension or mixing chopped galled roots with the
oil. Each entry of the test crops was replicated 3 times. Examination
'or root galls or knots was done 2 months after inoculation. The degree
)f galling was numerically rated 0 for no galls, 1 for slight, 2 for trace,
Sfor moderate, and 4 for severe. The 47 entries of tobacco and 13 of
omato were highly susceptible and all of them had a rating of 4. Of the
F eggplant entries, only variety Long Purple Slender had a rating of 3.3,
suggesting moderate susceptibility. In sweet pepper, varieties World Beater
Lnd Dingras Rainy Season had ratings of 1.6 and 0.6, respectively; two
collectionss of Bontoc Sweet Long had a rating of 0, demonstrating appre-
:iable degree of resistance; both are promising materials for crossing with
uscentible commercial varieties such as California Wonder and Penner
, Leaf shredding in Saccharum spontaneum and its relation to oo0s
production of Sclerospora spontanea. A. M. Pedrosa, Jr. Cross loni
dinal sections of infected leaves of Saccharum spontaneum L. revealed
the hyphae of Sclerospora spontanea Weston were intervascularly par
to the fibrovascular bundles. They were invariably intercellular wi
the mesophyl parenchyma; lateral spread was restricted by the thick-wa
scierenchyma of the large vascular bundles.
Qogonia were initiated by enlargement of the tip of. a hyphal br;
or formed from a swelling of the main hyphae. The antheridium .
firmly appressed to the oogonium and was observed early in the devc
ment of the oogonium. Both organs were multinucleate, as observed
infected tissues stained with safranin fast-green. Each cogonium conta
from 8 to 32 nuclei and the antheridium had 4 to 8 nuclei. The sh
ding of the infected leaf resulted from the destruction and collapse of
mesophyl tissues between the vascular strands occasioned by the enl
ment of numerous oospores, 48-55 y in diam with 3.6-5.5 pt spore w
A new species of nematode associated with cedar cones in England
A. C. Pizarro. Panagrobelus petersi is a new species of nematode fo
in cedar (Cedrus atlantica Manetti) cones at Silwood Park, Sunning
Ascot, Berkshire, England. It has both cephaloboid and panagrolain
morphological features. Based on these characteristics, a creation of a
family to bridge the gap between the families Panagrolaimidae and Ce
lodidae is suggested. Thus, the family Panagrolaimidae, subfamily P
the methods of ,inoculation; the prick method was the most effective.
Based on' its cultural, morphological, and physiological characters, and
n accordance with the "new host-species concept," the authors propose
he name Xanthomonas nepheliae sp. n.; the specific epithet refers to the
lost plant whose generic name is Nephelium.
1- Soil and seed& treatment with Demosan against damping-off of-cruci-
'ees. A. N., Pordesimo anid B. B. Tamayo. The effectiveness of Demo-
an (l,4-dichloro-2,5-dimethoxybenzene) as a soil- and seed-treatment chemi-
:al- against damping-off of crucifers was tested using pechay, cabbage, and
:auliflower as indicator plants and Pythium debaryanum Hesse as test
ungus.. For soil treatment, Demosan was applied as in-furrow dust in
ieedflats at 0.5, 1.0, and 2.0 lb a.i. per acre; it was more effective at 1.0
b a:i./acre. For seed treatment, it was applied as dust at 4, 5, and 6
)Z/100 lb seed; the first 2 lower rates were more effective. At the 3 rates
n. each method of application, Demosan invariably improved seed emer-
gence in artificially-infested soils and minimized Pythium-damping-off of all
he 3 crucifers.
Greenhouse test of Benlate for the control of powdery mildew :of mung
Pean. F. C. Quebral. Benlate (1-butylcarbamoyl-2-benzimidazole car-
)amic acid, methyl ester) showed systemic activity against powdery mildew
>f mung bean (Phaseolus aureus L.) when incorporated into 400 cm3 soil
Lt the rate of 0.5, 0.25, 0.15, and 0.07 g of 50% active ingredient formula-
ion. At the 4 rates, it protected the plants throughout the experi-
nent. It was not phytotoxic. Based on this test, Benlate should be further
ested in the field for the control of mung bean powdery mildew.
Sheath rot or stem canker of sugarcane. T. T. Reyes, Victoria B.
.osete, and Victoria M. Ela. The disease affects primarily the leafsheaths.
Uso the upper exposed joints, standing stalks, and deteriorating seedpieces
mn the groundare being affected. On the leafsheaths, the lesions first ap-
)eared as irregular; light salmon-orange areas. As the lesions enlarged, they
)ecame brick red. In the advanced stage, the central portion of the lesions
turned pale gray and was dotted with black pycnidia. The affected leaf-
heaths became: firmly attached to the stem as they dried. Lesions on
eaves were light to bright red and elliptical in appearance. They- were
usually found at the lower half of the leaf blade.- Severely infected leaves
vilted, drooped and dried. On the stalk, the lesions first appeared as
pindle-shaped and' slIgltly sunken reddish areas. They rapidly increased. in
ize, became grayish and covered with. pycnidia. Affected young. stalks were
quicklyy killed. '
size of hyphal cells was 5.3 x 58.bi L. Pycnidia were stromatic, wnite wnei
young and black when mature, hard, thickwalled, valsoid, with irregula:
base diameter of 0.96 mm, and average length of 2.45 mm. Pycnospore
chambers, and with long necks measuring from 1.2 to 2.0 mm, with average
with average size of 3.28 x 2.03 it, were hyaline, 1-celled, ovate or cylindri
cal, straight or slightly curved, and with obtuse ends.
For mycelial growth, the optimum temperature was between 24 anc
32 C and the optimum pH was between 3 and 5.5. Abundant pycnidi,
were produced between 28 and 32 C, and pH 3 and 3.5. The fungus grev
and sporulated well on malt extract agar, Leonian's agar, and coconut wate:
agar at pH 4.5.
Suscept range of rice tungro virus. C. T. Rivera, K. C. Ling, an(
S. H. Ou. The suscept range of rice tungro virus "S" strain was studies
using 63 species and varieties or selections, including several species of wik
rice in 8 tribes in the Gramineae. These were inoculated by the leafhoppe
vector, Nephotettix impicticeps Ishihara, that first fed on caged infected rio
var. Taichung (Native) 1. Several species of wild rice (Oryza spp.) were
suitable suscepts of tungro virus. Certain weeds or small grains developed
symptoms similar to those of tungro. No symptoms appeared on any o
the other test plants. Infection was less than 6% on all plants, excep
Oryza spp. that have more than 50% infection. The virus was recover(
easily from wild rice by inoculation to Taichung (Native) 1. It was diffi
cult to recover the virus from infected weeds back to rice. The following
13 species, grouped according to tribes, had one or more infected plant
ANDROPOGONEAE Ischaemum rogosum Salisb., and Sorghum vulgar,
Pers. var. Darso; ERAGROSTEAE Dactyloctenium aegyptium (L.) Beauv.
and Eragrostis tenella (L.) Beauv.; ORYZEAE Leersia hexandra Swartz.
Oryza rufipogon Griff., 0. officinalis Wall., 0. ridleyi Hook., 0. barthi
A. Chev., and 0. sativa L. var. Taichung (Native) 1. PANICEAE Pas
palum scrobiculatum L., and Setaria glauca Beauv. var. Proso; TRrTICE
- Triticum vulgare Vill var. Fiorello. All the test plants except Oryz
spp. were poor hosts of the leafhopper. The average survival time of thi
insect on most of the plants was less than 4 days. Completion of the lifi
cycle (egg to adult) occurred easily on all Oryza spp. but not on other plan
species. Egg deposition was relatively low on most of the test plants an<
was considered negligible in this study.
Because N. apicalis, a newly found vector of rice tungro virus, cor
only thrive on the paddy weed, Echinochloa colonum Link, transmission
of tungro virus by this insect to E. colonum was performed. But n<
symptoms appeared on E. colonum inoculated by caging 3462 viruliferou
insects on 115 plants in 5 trials. In previous reports elsewhere, rice tungre
virus was transmitted by Nephotettix spp. from rice to E. colonum and bad
L V '" i
Nos. I & 2] ABSTRACTS 17
to rice. Although some of the weeds were found susceptible, their im-
portance appeared doutbful since most of the test weeds were poor hosts
of the vector N. impicticeps. Because of the dependence of N. impicticeps
on 0. sativa, it appears that wild rice species may play a more important
role in the transmission of the disease in the field than some of the com-
mon paddy weeds.
Transmission of two strains of rice tungro virus by Recilia dorsalis. -
C. T. Rivera, K. C. Ling, S. H. Ou, and V. M. Aguiero. Two strains
of rice tungro virus ("S" and "M") from 3 different sources were trans-
mitted to a differential rice variety FK-135 by a new vector, Recilia dorsalis
(= Inazuma dorsalis Motsch.). Test insects, allowed to feed 2 to 3 days
on infected plants, transmitted strains "S" and "M" at the rate of about 8
and 6%, respectively. In both strains, low percentage of infected plants
was obtained with insects tested immediately after they were given a 12-hr
or shorter feeding on virus-source plants. Infectivity was retained by some
of the insects for as long as 4 days in daily serial transfers; no infection
occurred beyond 4 days. When this insect was given access to infected plants
at all times, it transmitted the virus throughout their lives. The 4 col-
lections of R. dorsalis from various localities differed slightly in efficiency
of transmtting "S" or "M" strain of the tungro virus. The results indicate
that R. dorsalis is able to transmit the tungro virus and that the transmission
pattern of the virus is similar to that observed on the other 2 vectors
(Nephotettix impicticeps and N. apicalis). Like N. apicalis, R. dorsalis has
a lower percentage of active transmitters than N. impicticeps.
Notes on the field incidence of banana mosaic in the Philippines. -
N. I. Roperos. The occurence of banana mosaic in a commercial plant-
ing of Giant Cavendish, imported from Honduras and Costa Rica by the
Standard (Philippine) Fruit Corporation in August 1966, was first observed
in General Santos, Cotabato on 3 December 1966. Diagnostic symptoms of
mosaic appeared 2Y3 to 3 months after planting the originally imported
seedpieces and those obtained from them to plant a second seedbed. The
disease rating has not exceeded the 0.5% level and is not yet alarming. The
highest rating was 0.07% in the originally imported seedpieces and 0.06%
in the second seedbed at General Santos, Cotabato. In the experiment
station at Davao City where the same company subsequently established a
third seedbed of 90 hectares in June 1968, the symptoms appeared 1 month
after planting which is 1Y months earlier than that in Cotabato. Disease
rating was 0.012% in August 1968. Early appearance of symptoms in either
location indicated that some of the imported seedpieces were originally in-
The masked symptom or absence of distinct mosaic pattern in more
mature and older plants makes inspection for disease incidence and eradica-
tory measures rather difficult.
A hitherto unreported species of Curvularia pathogenic to rice in the
Philippines. P. A. Santamaria, A. Benoit, and S. B. Mathur. A specie
of Curvularia was observed on rice grains in blotter tests 8 days after in
cubation under near-ultraviolet light at 22 C. The fungus was isolated
into pure culture and was studied for its morphology and pathogenicity
Initial symptoms on inoculated rice seedlings appeared as brownish lesion-
on the leaf. As the disease progressed, they developed into irregular lineal
spots. After 3 weeks, the brown-bordered spots became darker, coalesced
and formed a more pronounced spot on the leaves.
Conidiophores on rice seed were dark brown with conidia arranged ir
spiral fashion or whorls of 2 to 3. The black conidia were long, straight
and elliptical or ventricose-fusiform, shiny by reflected light. On PDA
colonies were dark with black zonate growth. Conidiophores were simple
straight or flexous, geniculate, septate, smooth-walled, reddish-brown, witl
lighter tip. Conidia were acropleurogenous, straight or curved, elliptical o:
ventricose-fusiform, obconical at the base with a protuberant hilum. Coni
dia were usually 4-septate, dark reddish-brown with the 2 end cells pale
and smooth-walled measuring 40.1-68.8 x 11.1-16.6 [t, or an average of 59.6 :
12.9 [t. These morphological and colony characteristics are identical wit]
those of Curvularia cymbopogonis (C. W. Dodge) Groves and Skolko. Thi
is a new record of C. cymbopogonis pathogenic to rice in the Philippines
Rice var. BE-3, IR-8, and Dinalaga were infected; infected seeds range
from 0.25 to 3.25%. The fungus appears to be a weak parasite but ma'
become a serious pathogen once it is established in the field.
Plants affected by air pollution. P. S. Subido, P. A. Santamaria
Encarnita Abella-Espada, Estela Novero-Alqueza, and A. C. Pizarro. Pe
riodic field investigations have shown that gases, emitted by fertilizer fac
stories, can partially or completely defoliate santol, mango, avocado, an<
chico. At first their leaves showed burnt edges and tended to curl up
wards, then they finally dropped. Die-back of twigs was very common oi
affected trees. Continuous emission of toxic gases resulted in death o
plants. Among the affected trees, santol appeared to be very susceptible
while chico was quite tolerant. Among the vegetable crops, tomato an
sweet potato wer extremely susceptible; eggplant and okra were mor,
tolerant. Rice and corn became stunted. The abiotic agents that are likely
causing this disorder are sulfur dioxide and hydrogen flouride. The al
fected areas appeared to be oriented with wind direction.
Plant parasitic nematodes associated with citrus decline in Batangas. -
Apolinaria Trinidad and R. G. Davide. To determine the number an<
kind of nematodes associated with the citrus decline in the province o
Batangas, a total of 123 composite soil samples were collected from several
Nos. 1 & 21 ABSTRACTS
The new wonder fungicide
A systemic and effective control for
powdery mildew in cucumbers and melons
Applied to the soil and taken up through the roots
One application can give several weeks protection
Translocation in the plant ensures disease control
'Milcurb' eradicates mildew attack in 2 to 3 days
MILCURB is a product of PLANT PROTECTION, LTD.
Agricultural Division, IMPERIAL CHEMICAL INDUSTRIES, England.
Exclusive distributor in the Philippines:
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HONGKONG BANK BLDG., JUAN LUNA, P.O. BOX 294, MANILA, TEL. 47-00-41
Branches: loiolo Cebu Bacolod
Nos. 1 & 2] EUSEBIO: WOOD DECAY FUNGI
X IIIIIppICi1iJ 10 UAiIC;Xy 11111LCU. XI IladJCI VICCIL3 LIC lclaLVC UcaLL Ul-LlV
capacity of 18 species of Philippine fungi on 2 species of Philippine wood.
MATERIALS AND METHODS
The relative decay capacity of 18 species of cultured wood-decay fungi
in the Philippines was measured by loss in weight of the inoculated wood.
Except for the use of malt agar (Difco bacto malt extract, 25 g; agar, 18
g; distilled water, 1 liter) instead of soil medium, and bent glass rod instead
of feeder block for support, the standard procedure of the American So-
ciety for Testing and Materials (ASTM, 1965) was followed to accelerate
the test for natural-decay resistance of wood.
Two commercially important species of Philippine wood, i.e., apitong
(Dipterocarpus grandiflorus Blanco) and yakal (Shorea astylosi Foxw.) were
used. The samples were heartwood obtained from trees of similar size and
approximately of the same vertical and radial position. These were sawn into
sign consisting of 3 replications, and incubated in the dark except for short
blocks 2.5 x 2.5 x 0.9 cm, with the shortest dimension along the grain.
Adjustment blocks were provided for equilibrium-moisture content weight
The relative growth rate of 24 cultures, representing the 18 species of
wood-decay fungi at 10 temperature levels (16, 20, 24, 28, 32, 36, 40, 44, 48,
and 52 C) was determined on malt-agar plates arranged in a factorial de-
sign consisting of 3 replications, and incubated in the dark except for short
periods of observation. Small plugs of mycelium from actively growing cul-
PI-T TppIMINt PiVTOPATWOT OfV
tures (7-day old) of the test fungi were transferred i
-------- C"*03' -----------Jo- I- --
radial growth was measured in mm to represent the average of at least 2
different measurements per plate. In the first trial, 90-mm plates were used.
When plates were fully covered before the end of the 8-day incubation period,
a second trial was conducted on plates 140 mm in diam to determine the
growth for the 8-day period.
To determine the oxidase reaction of the different isolates of the test
fungi, gallic-acid and tannic-acid agar media were used in accordance
with the method described by Davidson et al. (1938).
Gallic-acid and tannic-acid agar plates were prepared in triplicates for
each culture. Radial growth in plates were measured 1 week after inocula-
tion. Oxidase reaction on the media was evaluated using the method des-
cribed by Nobles (1948).
RESULTS AND DISCUSSION
Relative decay capacity of the test fungi. The relative destructive capa-
city of the 18 species of fungi on 2 species of Philippine wood is summarized
in Table 1. The decay capacity of each fungus isolate is expressed as a mean
percentage weight loss of 5 blocks for each of the 2 wood species. From the
average weight-loss values, the results show that yakal is more decay-resistant
than apitong. Of the test fungi, only Pleurotus sajor-caju, Polyporus rubidus
and Fomes lividus caused appreciable weight loss in yakal. On the other
hand, all species except Trametes insularis caused appreciable weight loss
To compare more directly the relative decay capacity of all the test
fungi, the average percentage of mean weight loss for apitong and yakal was
calculated for each isolate (Table 1). From the average values of mean
weight loss, 14 species were noted to cause considerable decay, ranging from
4.75 to 30.6%. The most destructive species appeared to be Fomes lividus,
a white-rot fungus, followed by Polyporus rubidus, a brown-rot fungus. The
least destructive were Trametes punicea, Polyporus versatilis, Daedalea elegans,
andTrametes insularis which caused average mean-weight losses ranging from
1.54 to 2.95%.
Direct comparison of weight losses caused by white- and brown-rot fungi
was not possible inasmuch as there were only 3 brown-rot fungi while there
were 15 white-rot fungi. However, all the 3 brown-rot fungi caused con-
siderable decay with an average mean-weight loss of 12.9% for Lenzites striata,
20.46% for L. subferruginea, and 23.69% for Polyporus rubidus.
Trametes insularis and Daedalea elegans caused the least decay in api-
tong and yakal. Based on records (Murrill, 1908; Teodoro, 1937) and speci-
nens examined, T. insularis has been collected only on fallen logs of Ben-
n notri nltr. mrnntain-
Nos. 1 & 2] EUSEBIO: WOOD DECAY FUNGI 23
TABLE 1. Relative decay capacity of fungi on apitong and yakal, expressed as
per cent weight loss
Per cent weight loss (110-day exposure)a
Test Fungi No. Average Mean
Apitong Yakal Weight Loss
Fomes lividus 408 53.63 7.56 30.60
Polyporus sanguineus 224 30.82 1.50 16.16
518 25.06 2.03 13.55
Pleurotus safor-caiu 365 20.90 8.57 14.75
Polyporus maximus 374 25.05 1.98 13.52
401 15.97 1.74 8.86
376 15.42 1.73 8.76
Phaeophlebia strigosa-zonata 405 23.99 1.95 12.91
Poria medulla-panis 404 17.03 5.14 11.09
Trametes aspera 370 19.84 1.37 10.61
T. roseola 489 18.70 1.83 10.27
Daedalea flavida 47 14.73 3.75 9.27
148 11.12 1.87 6.50
Trametes corrugata 462 8.80 1.84 5.32
Poria vincta 402 7.84 1.66 4.75
Trametes punicea 487 4.50 1.75 3.13
Polyporus versatilis 383 3.81 2.09 2.95
398 1.78 1.73 1.76
Daedalea elegans 390 2.41 1.25 1.83
10 1.64 1.35 1.50
Trametes insularis 429 1.66 1.42 1.54
Polyporus rubidus 524 36.14 11.23 23.69
Lenzites subferruginea 508 39.37 1.55 20.46
L. striata 86 23.90 1.89 12.90
Average of 5 test blocks of apitong and yakal.
guet pine. This indicates the limited ability of this fungus to rot heartwood
of hardwood species such as yakal and apitong. Daedalea elegans has limited
decay capacity in heartwood of the test hardwood species since this fungus
is confined to sapwood.
The limited decay caused by Trametes punicea and Polyporus versatilis
is due to their slow development in short-period laboratory-decay tests. How-
ever, both species are reported to be associated with serious decay of railroad
ties and wooden posts, used for many years. Polyporus versatilis is associated
with wood decay in automobiles in the tropics (Humphrey, 1931).
In general, my results, that fungi causing deterioration of wood products
vary widely in their ability to produce decay, agree with those of earlier
workers (Humphrey, 1915; Schmitz, 1921; Reinking and Humphrey, 1931).
My results also showed that the rate of growth of fungi on agar media is
not indicative of their capacity to rot wood. This was illustrated by Lenzites
TABLE 2. Optimum and inhibitory temperature for radial growth of the test fungi
Isolate Temperature in C
Test Fungia No. Optimum Inhibitory
Trametes insularis 524 28 40
Polyporus rubidus 429 28 36
Daedalea elegans 390 32 40
Lenzites subferruginea 508 32 40
Phaeophlebia strigosa-zonata 405 32 40
Polyporus maximus 401 32 40
P. versatilis 398 32 40
Poria vincta 402 32 40
Daedalea elegans 10 82 44
Polyporus maximus 376 32 44
Lenzites striata 86 32 48
Pleurotus sajor-caiu 365 36 44
Polyporus versatilis 383 36 44
Trametes aspera 370 36 44
T. corrugata 462 36 44
Fomes lividus 408 36 48
Polyporus sanguineus 518 36 48
Poria unita 404 36 48
Trametes roseola 489 36 48
Daedalea flavida 47 36 52
148 36 52
Trametes punicea 487 40 48
Polyporus maximus 374 40 52
P. sanguineus 224 40 52
a Grouped according to optimum temperature for growth.
subferruginea, L. striata, and Polyporus maximus which grew well on malt
agar but caused limited decay in yakal. This finding also supports the view
expressed by Humphrey (1915) that the heartwood of green-heart tree was
resistant to most of the fungi tested despite their luxuriant growth on culture
Temperature relations. The optimum temperature for radial growth
of the test fungi ranged from 28 to 40 C (Table 2). Listed in the order
of increasing optimum temperature requirement, the fungi were arbitrarily
categorized into 4 groups. Of the 18 species, only Polyporus rubidus and
IEBIO: WOOD DECAY FUNGI
rametes insularis had optimum growth temperature of 28 C. One isolate
ch of P. maximus, P. sanguineus and Trametes punicea had an optimum
mperature of 40 C. The rest had optimum temperature of either 32 or
C. Not all isolates of the same species had optimum growth at the same
mperature. Inhibitory temperature varied considerably among the 24 iso-
Most of the test fungi showed maximum growth at both 32 and 36 C
at an optimum temperature range of 28 to 40 C. These results are at
riance with those of Humphrey and Siggers (1933) who investigated the
mperature relations of 56 species of wood-destroying fungi commonly found
the U.S. and Cuba. Their results indicated that for most of their test
ngi, the optimum temperature range was between 24 and 32 C. Cart-
right and Findlay (1958) reported that the optimum temperature for
owth of the majority of the important European species lay between 25
Id 30 C. Four species of fungi included in my study were also studied
.rlier by Humphrey and Siggers (1933). Their results have been presented
id discussed but the difference in media, isolates, and temperature inter-
ils used in our separate studies does not permit direct comparison of our
. Lindgren (1933) found that the temperature that favored mycelial growth
Certain fungi also favored development of decay. But Cartwright and
indlay (1958) reported that most rapid decay of wood occurred at 2 C to
C below the optimum growth temperature on malt agar. The difference
i optimum temperature for rate of wood decay and rate of mycelial growth
in be explained by the fact that experiments involving loss of weight in
ood blocks lasted several months whereas measurements of growth rate on
gar only entailed a brief period of 1 to 2 weeks. It is possible that a
ownward shifting of the optimum temperature may have occurred after
rolonged exposure to these rather critical temperature changes. It is also
conceivable that if growth-rate studies on malt agar were conducted in large
mntainers over extended periods, as in wood-decay experiments, the optimum
temperature for mycelial growth on agar and decay of wood may be the
Oxidase reaction. The nature of the reaction and growth of the test
solates on gallic- and tannic-acid containing media are shown in Table 3.
"he data and observations were based on triplicate cultures. The appearance
nd relation of the brown diffusion zone was rated according to the system
f Nobles (1948). The decay type was based on 5 replicate blocks of api-
ong. Because the wood used has normally dark-colored heartwood, the
leaching effect and fibrous nature of the wood residue was prominent
here decay was caused by white-rot fungi. With the brown-rot fungi, the
ecayed wood turned brown and crumbled when pressed between the fingers.
rubidus exhibited negative oxidase reaction on both gallic- and tannic-a
media and caused a distinct brown rot in the test blocks. Other species t
isolates exhibited a well-defined positive reaction on both gallic and tam
acid media although not all caused a distinct white rot. Both isolates
Daedalea elegans, one isolate of Polyporus versatilis, and the single isol
of Trametes insularis did not cause a distinctive type of rot.
Results of the decay-capacity experiment showed that all isolates cau=
a very slight decay on the test blocks exposed for 110 days (Table 1).
more distinct type of decay might have been exhibited had the blocks bx
exposed for longer periods. D. elegans, reported to be found in sapwo
caused a white rot. This explains why the fungus did not cause a distil
type of white rot on the heartwood test blocks. Although 1 of the 2 isola
of P. versatilis (Isolate 398) did not cause a distinct type of white rot, Isol;
383 did. This can be attributed to variation in decay capacity between
isolates of the same species. Both isolates, however, had a strong posit
oxidase reaction on gallic- and tannic-acid media. Isolate 383 had a higl
decay capacity than Isolate 398. Although weight losses involved were at
low level, Isolate 383 caused enough decay to exhibit a white rot on t
heartwood test blocks.
Trametes insularis, found only on Benguet pine logs, caused a minin
amount of weight loss on heartwood test blocks. This could have produce
a more distinct type of decay had the sapwood blocks of a softwood be
used. The fungus exhibited a strong positive oxidase reaction on be
gallic- and tannic-acid media.
Among the brown-rot fungi, only Lenzites striata yielded oxidase
action that conformed with that of Davidson et al. (1938). This test fung
exhibited a negative oxidase reaction on either gallic- or tannic-acid mec
and better growth occurred in the former medium. That the different t,
fungi had varying growth rate on gallic- and tannic-acid media can
gleaned from Table 3.
In the light of the present study, it can be deduced that the 3 space
of fungi, exhibiting negative oxidase reaction on both gallic- and tannic-ac
media, caused typical brown rot on the test wood blocks. Of the remain
15 species, exhibiting strong positive oxidase reaction on both media, 2 caus
an indistinct type of rot and 13 species caused rots that were distinctly
the white-rot type.
EUSEBIO: WOOD DECAY FUNGI
TABLE 3. Comparison of oxidase reaction of wood-decay fungi and the kind of rot
they produce on test wood blocks
S. Oxidase Reaction
Isolate Gallic acid Tannic acid Kind
Test Fungi No. of rot
Growth Growth produced
F Rate* (mm) Rate Imm)
Phaeophlebia strigosa-zonata 405 VSR 2 SR 30 white
Daedalea elegans 10 VSR 0 VSR 3 indistinct
390 VSR 0 VSR 2 indistinct
D. flavida 47 VSR 0 SR 27 white
148 VSR 0 SR 23 white
Fomes lividus 408 VSR 0 SR 25 white
Lenzites striata 86 17 5 brown
L. subferruginea 508 27 0 brown
Pleurotus sajor-caiu 365 SR 18 SR 21 white
Polyporus maximus 374 VSR 0 SR 25 white
376 VSR 0 SR 22 white
401 VSR 0 SR 20 white
P. rubidus 524 35 35 brown
P. sanguineus 224 VSR 0 SR 23 white
518 VSR 0 SR 22 white
P. versatilis 383 VSR 0 SR 0 white
398 SR 0 SR 0 indistinct
Poria medulla-panis 404 VSR 9 SR 16 white
P. vincta 402 VSR 0 SR 18 white
Trametes aspera 370 VSR 0 SR 0 white
T. corrugata 462 VSR 0 SR 0 white
T. insularis 429 VSR 0 SR 0 indistinct
T. panicea 487 VSR 0 VSR 0 white
T. roseola 489 VSR 0 SR 26 white
aVSR . . very strong recation
SR . . strong reaction
. . negative
AMEmICAN SOCIETY FOR TESTING AND MATERIALS (ASTM). 1965. Tentative method for
accelerated laboratory test of the natural decay resistance of woods. Supplement
Part 16, D2017-63: 673-680.
BAVENDAMM, W. 1928. Uber das vorkommen und den nachweis von oxydasen bei
holzzerstorenden pilzen. I. Mitteilung Zeitzchrift fur Pflanzenkrankbeiten und
Pflanzenshutz 38: 257-276.
CARTWRIGTH, K. ST. G., & W. P. K. FINDLAY. 1958. Decay of timber and its prevention.
Dept. Sci. Ind. Res. His Majesty's Stationary Office, London.
DA COSTA, F. W., & R. H. KERRIUSH. 1965. The comparative wood destroying ability
and preservative tolerance of monokaryotic and dikaryotic mycelium of Lenzites
trabea (Pers.) Fries and Poria vaillantii (DC. ex Fries) Cke. Ann. Bot 29: 241-252.
Nos. 1 & 2]
saying fungi by their reactions on gallic or tannic acid medium. J. Agr. Res.
:REY, C. J. 1915. Test on the durability of greenheart (Nectandra rodiaei
somb.). Mycologia 7: 204-209.
:REY, C. J. 1931. Decay of wood in automobiles in the tropics. Philippine
Sci. 46: 189-198.
:REY, C. J., & P. U. SIGCERS. 1933. Temperature relation of wood destroying
igi. J. Agri. Res. 47: 997-1008.
N, R. M. 1933. Decay of wood and growth of some hymenomycetes as
ected by temperature. Phytopathology 23: 73-81.
C. S. 1955. Laboratory tests of some commercial species of mahogany. Forest
)d. J. 5: 149-152.
,L, W. A. 1908. Additional Philippine Polyporaceae. Torrey Bot. Club Bull.
,M. K. 1948. Studies in forest pathology. VI. Identification of cultures
wood rotting fungi. Canad. J. Bot. C, 26: 281-431.
k, M. M. 1965. Cultural studies of Fomes fraxinophilus (Peck) Cooke, and
mes ellisianus Anderson. Ph.D. Dissertation. State Univ. College of Forestry
Syracuse Univ. 194 p.
Gi, O. A. & C. J. HUMPHREY. 1931. Laboratory tests on the durability of
ilippine woods against fungi. Philippine J. Sci. 45: 77-92.
z, H. 1921. Concerning the durability of the wood of the maidenhair tree. J.
rest. 19: 165-166,
ER, T. C., & C. G. DUNCAN. 1947. The decay resistance of certain Central
lerican and Ecuadoian woods. Topical Woods 92: 1-24.
PATHOGENICITY TEST OF FOUR GENERA OF PLANT
PARASITIC NEMATODES ON VEGETABLE CROPS
A. G. DE LA ROSA AND R. G. DAVIDE
Former undergraduate thesis student and Assistant Professor, respectively, Depart-
ment of Plant Pathology. UPCA, College, Laguna, Philippines E-109.
Supported by UPCO Research Fund under Project No. 234.
Accepted for publication 27 October 1969.
The different crops showed varying degrees of growth reaction to nematode
infection. Plants inoculated with Pratylenchus generally showed reduction in top
and root growth. In garlic and lettuce, the top growth reduction was 31.7%
and 29.4%, respectively. The other crops showed less than 10% reduction.
Root growth reduction was generally higher than that in top growth. A
similar trend of result was obtained in plants inoculated with Tylenchorhynchus.
Stunting of plants was very evident among the inoculated plants of cabbage
(50.5%), eggplant (31.4%), and garlic (29.5%). Only onion and mustard
showed resistant reaction to this nematode.
The response of crops to Helicotylenchus was generally different from
their response to Pratylenchus and Tylenchorhynchus. Plants inoculated with
Helicotylenchus and Hemicycliophora showed less than 30% reduction in top
and root growth.
The reproduction of the 4 nematodes varied greatly with the different
crops. Pratylenchus population increased to as high as 251% in tomato
and 156% in eggplant within 2 months. On the other crops, the nematode
population also increased. The population build-up of Tylenchorhynchus, Heli-
cotylenchus, and Hemicycliophora was much lower than that of Pratylenchus.
This study has shown that nematode attack can cause poor growth
of top and root. But there is evidence suggesting that some crops can
withstand high nematode population without sustaining any appreciable re-
duction in growth.
Nematodes are known to cause considerable damage on different agricul-
tural crops. It has been reported elsewhere that nematode infection alone
can cause as much as 50% reduction in crop yield (Whitehead, 1956). There
are a number of nematode species that can cause considerable damage on
vegetable crops. For instance, Piatylenchits penetrans Sher and Allen was
found attacking potatoes which resulted to a significant reduction in plant
growth (Cobb, 1917; Oostenbrink, 1959). Evidently, this species of nematode
has a wide host range as it attacks 33 plant species in Oregon, U.S.A. (Jen-
sen, 1953). On the other hand, Krusberg (1956, 1959) has demonstrated
L - -
toni Steiner while pepper, mustard, cucumber, and Crotolaria spectabilis
were resistant. Van Gundy (1959) has shown that Hemicycliophora arenaria
Raski can parasitize tomato and a number of herbacious plants. Christie
(1959) has shown that a species of Trichodorus causes considernhlpe rlmacr
.. -- .--.
nt species of nematodes,
'athogenicity of root-knot
vegetables in Benguet Proi
Trichodorus christie Alle
iae (Zimmermann) Gold
with the different veg
capable of causing consi
ermine the pathogenic c
;, Hemicycliophora, and
-racysencnus, nemzcyctzopnora, neticotylencnus,
'xtracted from soil samples collected from the
vince has sho
en, and Xip
and Tylenchorhynchus were
Baermann funnel methods.
t besides ti
za spp. we
t area. W]
s) on vege
Nos. 1 & 2] DE LA ROSA & DAVtDE: PARASITIC NEMATODES OF VEGETABLES 31
Crop reaction to nematode infection. Data on the measurements of
growth based on plant height and root weight are presented in Tables 1-4.
The different crops showed varying degrees of growth reaction to nematode
infection. There were cases where growth reduction was more pronounced
in the roots than on the tops or vice versa.
The results obtained in plants inoculated with Pratylenchus showed that
top growth of garlic was reduced by 31.7%, lettuce by 29.4%, while the
other crops showed less than 10% reduction. On cabbage, no growth
reduction was detected; there was very slight reduction on eggplant. Growth
reduction on roots was generally higher than the top growth. Some crops
TABLE 1. Effect of Pratylenchus infection on the growth of 10 vegetable crops,
2 months after inoculation
Plant Height (cm) Per cent Weight of Roots (g) Per cent
Crops Inoculateda Controlb reduction Inoculateda* Controlb reduction
Cabbage 29.25 29.85 11.38 15.50 26.5
Eggplant 48.65 49.05 0.8 32.85 34.00 3.4
Garlic 25.27 37.00 31.7 8.28 14.15 40.8
Lettuce 16.22 21.00 29.4 11.09 13.20 16.2
Mustard 19.57 21.55 9.1 7.55 9.00 16.1
Onion 23.85 26.00 8.3 15.63 14.25 -
Pechay 24.37 25.50 4.4 6.45 8.40 23.2
Pepper 43.87 48.55 9.6 18.10 20.75 12.8
Potato 46.45 48.60 4.4 18.35 39.35 53.4
Tomato 47.22 52.00 9.2 23.73 38.90 38.9
a Mean of 8-plant replicates.
b Mean of 4-plant replicates.
TABLE 2. Effect of Tylenchorhynchus infection on the growth of 10 vegetables crops,
2 months after inoculation
Plant Height (cm) Per cent Weight of Roots (g) Per cent
Crops Inoculateda Controlb reduction Inoculateda Controlb reduction
Cabbage 14.27 29.90 50.5 7.80 11.60 32.7
Eggplant 33.00 48.10 31.4 14.68 30.85 52.4
Garlic 28.30 40.15 29.5 4.78 15.25 68.6
Lettuce 22.05 24.75 10.9 8.80 16.00 45.0
Mustard 25.15 19.65 8.55 8.75 2.1
Onion 27.37 27.25 14.28 14.65 2.5
Pechay 21.95 26.30 17.2 6.68 7.75 13.0
Pepper 28.75 47.35 16.88 19.05 11.4
Potato 42.80 48.30 11.4 20.85 38.10 45.3
Tomato 47.30 53.15 11.0 19.55 32.75 40.3
SMean of 8-plant replicates.
b Mean of 4-plant replicates.
2 months after inoculation
Plant Height (cm) Per cent Weight of Roots (g) Per cent
Crops Inoculatedn Controlb reduction Inoculateda Controlb reduction
bbage 27.15 25.55 10.13 11.25 9.9
gplant 53.70 51.50 26.70 30.55 12.5
.rlic 29.27 41.40 29.3 12.25 15.50 20.9
ttuce 24.25 21.25 10.18 13.95 27.0
istard 19.47 20.75 6.1 9.10 9.30 2.2
aion 25.30 27.80 8.9 11.83 15.55 24.0
chay 24.57 23.50 8.80 7.80 -
pper 48.80 53.60 10.8 19.60 20.50 5.4
tato 43.80 48.60 9.8 37.03 39.05 5.2
mato 45.00 48.80 7.6 32.20 34.05 5.4
a Mean of 8-plant replicates.
b Mean of 4-plant replicates.
BLE 4. Effect of Hemicycliophora infection on the growth of 10 vegetable crops,
2 months after inoculation
Plant Height (cm) Per cent Weight of Roots (g) Per cent
Crops Inoculateda Controlb reduction Inoculateda Controlb reduction
bbage 29.77 26.70 8.58 10.25 16.2
plant 54.30 55.65 2.4 27.68 29.40 6.0
rlic 30.15 38.60 21.9 13.05 15.95 18.2
ttuce 18.85 20.55 8.2 14.38 14.00 -
istard 20.65 20.20 9,28 10.35 8.3
ion 27.52 28.30 2.8 12.33 13.50 8.7
:hay 29.15 23.75 8.45 9.00 6.1
?per 44.45 43.55 21.55 20.25 -
:ato 43.50 46.45 6.2 35.58 36.50 2.5
mato 48.80 47.60 29.23 33.55 12.9
a Mean of 8-plant replicates.
b Mean of 4-plant replicates.
I high percentage of root reduction but low top-growth reduction, e.g.,
tato showed 53.4% of root-growth reduction but have only 4.4% top
>wth reduction (Fig. 1). Likewise, cabbage had 26.5% root reduction but
reduction in top growth was demonstrable (Table 1).
Fig. 1. Root systems of potato: A) considerably reduced by Pratylenchus, and
Stop growth (Figs. 2 8c 3). Based on the percentage of root reduction,
irlic roots were reduced by 68.6% (Fig. 2), followed by eggplant with
2.4%, potato 45.3%, lettuce 45%, tomato 40.3%, and cabbage 32.7% root
'duction. On the other hand, there was only very little root reduction in
mustard (2.1%) and onion (2.5%) and they showed no top reduction in-
icating their resistance to infection by Tylenchorhynchus (Table 2).
The growth reduction by the different crops due to infection by Heli-
>tylenchus was somewhat different from that by Pratylenchus or Tylen-
lorhynchus. Based on the top-growth reduction data, eggplant, lettuce,
echay, and cabbage were not much affected by the nematode infection.
mong these crops, only pechay showed no evidence of root reduction. The
highest reduction in top growth was obtained in garlic (29.3%), while the
:her crops showed less than 10% top-growth reduction. Based on the root
-owth reduction, lettuce lost 27%, followed by onion 24%, and garlic
).9% root reduction although no top-growth reduction was detected. Slight
'duction was observed in mustard, potato, tomato, and cabbage (Table 3).
In the case of Hemicycliophora, the different crops showed more toler-
Ice to infection. Based on the percentage of top-growth reduction, to-
ato, pepper, pechay, cabbage, and mustard were not affected. Only gar-
: appeared more suitable host for this particular genus. It showed 21.9%
... ......... I.......
'ops and root systems of garlic grown in Tylenchorhynchus-infested so
RI ac onmnarrl with th0o anntlrn IA1
for fin d:
Fig. 3. Eggplant grown in Tylenchorhynchus-infested soil for 60 days (B), and
inoculated control (A).
he nematodes. The highest root reduction was only 18.2% for garlic which
Iso gave the highest reduction in top growth (Table 4).
Influence of the different crops on the rate of reproduction of nema-
odes. To determine the rate of reproduction of the 4 genera, counts of
he nematodes were made after examination of the plants. The results are
ummarized in Tables 5-8.
The rate of reproduction of Pratylenchus varied considerably with the
different crops. In tomatoes and eggplant, the nematode population in-
TABLE 5. Population buil-up of Pratylenchus on 10 vegetable crops, 2 months
Crops Initial Counta Final Countb Per cent Increase
Cabbage 1,168 1,737.25 49.0
eggplant 540 1,387.00 156.8
;arlic 1,125 1,733.50 54.1
Attuce 1,035 1,727.00 67.0
mustard 1,163 1,444.50 24.2
unionn 540 284.50 -
'echay 1,125 1,575.25 40.0
'epper 1,085 1,631.25 57.5
'otato 1,035 1,396.50 35.6
tomato 500 1,756.75 251.2
Initial count per pot.
I ,_, ,1 .
rABLE 6. Population build-up of Tylenchorhynchus on 10 vegetable crops, 2 months
- T-.- ~_-1*P- .^kTA a nr Tnf wr~qc A
a Initial count per pot.
k. M A --L&:-- t.A
VTrne 1 2I 91
creased to 251.2% and 156.8%, respectively, in 2 months. Other crops th;
also gave high percentage increase in nematode population were lettut
76( %) e er (57 5%) arlic (54 1%) cabba e (49% nd ch 40%
In onion, rrth
In onion, th
t 1 .
e nematode population was decre;
of the crop to the nematodes (Ta
iere was still 8% reduction in tc
ulation build-up of Tylenchorhyne
eggplant in contrast to that of P
reproduction rate of Tylenchorhyne
Ind 83.9% in the latter. In the
only from 23 to 46%. In onion, ]
: did not apparently reproduce. 1
was markedly reduced (Table 6).
reduction of Hemicycliophora als(
atly, 5 of the 10 crops tested were i
inion, eggplant, lettuce, pepper, an<
on was observed in tomato and pc
8% and 57.8%, respectively, in
followed by garlic (26.4%) and p
/* l i,', alA l.ay k v U
based by 47% indicating th
ible 5). Despite this decrea
much lower in t
is. In lettuce an
eased by 87.2% i
)ps, the populatic
echay, and mustar
tode population i
with the differed
SThe highest ra
e there was an i:
crops was ]
the other cr
that, aside I
genera. of p
age to lettu
rate of reproduction ol
that of the other 3 .
ined in potato with a 5,
inly less than 23% incre;
8.3%. The nematode
mustard. The population
in this country, it has be
oot-knot nematodes (Mel,
tic nematodes which are
pathogenicity tests ha'
'licotylenchus, and Hem
damage on a number of
own that a crop may be s
genera. For instance, i
ly; whereas, the populate
greatly reduced. Pratylen
rlic where it reduced to
icotylenchus did not caus,
on all thi
est rate o
: the lowes
n this stud
:tive to ou
nus but un
Another evidence on the variability of the crop's tolerance to nematode
infection is the fact that there are crops that can support a substantial pop-
ulation of the nematodes without showing any significant reduction in growth.
Tomato and eggplant are such good examples. In spite of the population
increase of 251.2% in tomato and 156.8% in eggplant, their top growth was
reduced only by 9.2% and 0.8%, respectively. On the other hand, cabbage
with only a 39% increase in Tylenchorhynchus population, had its top
growth reduced by 50.5%. But this crop is more or less tolerant to Praty-
lenchus since no top growth reduction was observed despite a 499 increase
Generally, the nematode effect on the plant growth was due to the at-
tack on the root system. It was observed that certain areas of the roots,
where the nematodes were apparently feeding showed necrosis or death of
the infected tissues. The characteristic root necrosis or lesions caused by
Pratylenchus was commonly observed in the more suitable hosts. Consi-
derable damage to the root system reduced growth and consequently, root
capacity to absorb nutrient and water from the soil was also affected and
as a result, there was stunting of the plant.
The findings which showed that some of our vegetable crops can be
suitable hosts for one group of nematodes and unsuitable for another group
should be considered in the formulation of effective control measures par-
ticularly in crop rotation programs.
CHRISTIE, J. R. 1959. Plant nematodes, their bionomics and control. Fda. Agr. Expt.
Sta., Univ. Fda., Gainsville. 256 p.
CHRISTIE, J. R., &. V. G. PERRY. 1951. Removing nematodes from the soil. Proc.
Helminthol. Soc. Wash. 18: 106-108.
COBB, N. A. 1917. A new parasitic nematode found infecting cotton and potatoes.
J. Agr. Res. 11: 27-33.
JENSEN, H. J. 1953. Experimental greenhouse host-range studies of two root-lesion
nematodes, Pratylenchus vulnus and P. penetrans. Plant Dis. Reptr. 37: 384-387.
KRUSBERn, L. R. 1956. Studies on the tassellate stylet nematodes. Phytopathology
46: 18 (Abstr.)
KRUSBERG, L. R. 1959. Investigation on the life cycle, reproduction, feeding habits
and host range of Tylenchorhynchus claytoni Steiner. Nematologica 4: 187-197.
OOSTENBRINK, M. 1959. An inoculation trial with Pratylenchus penetrans in potatoes.
Nematologica 3: 30-33.
VALDEZ, R. B. 1968. Survey and identification and host-parasite relationships of
root-knot nematodes occurring in some parts of the Philippines. Philippine Agr.
VAN GUNDY, S. D. 1959. The life history of Hemicycliophora arenaria Raski (Nema-
toda: Criconematidae). Proc. Helminthol. Soc. Wash. 26: 67-72.
WHITEHEAD, H. G. 1956. Plant-parasitic nematode important pathogen in tropical
THE CONTROL OF ROOT-KNOT NEMATODES AND WEEDS IT
CIGAR FILLER TOBACCO SEEDBEDS BY SOIL FUMIGATION
C. P. MADAMBA, C. G. GOSECO, AND P. L. BAGOYO
Respectively, Assistant Professor, and Instructor, UPCA Department of Enl
m-l-m, 0l-rr T -an on-l Arrnnn mist Philinninp Tnhnon Arrminitratinn .rnt
This study was undertaken to evaluate the elticacy of locally available
soil fumigants for the control of root knot nematodes and weeds in cigar
filler tobacco seedbeds.
MATERIALS AND METHODS
Seedbed preparation. Twenty seedbeds, 1 x 8 m, were prepared 20 cm
apart in an area that was previously observed to be heavily infested with
the root-knot nematodes. Before these beds were laid out, the entire area
was first plowed and harrowed alternately for two times. Undecayed weeds
were removed and the soil was pulverized. The beds were prepared in such
a way that they were approximately 4 inches above the ground level.
Seedbed treatment. Immediately after seedbed preparation, the seed-
beds were treated separately with the soil fumigants according to their manu-
facturer's recommendations as follows: 25 g per linear meter of Agrene 25G
(benzyl-N-methyl dithiocarbamate); 3.5 ml per injection at 12-inch centers of
D-D (dichloropropane-dichloropropene mixture); 2 ml per injection at 12.
inch centers of Edabrom (ethylene dibromide); and 1 lb per 9 sq m of
Dowfume MC-2 (methyl bromide plus 1.01% chloropicrin). Untreated seed-
beds were provided as controls.
The different treatments were replicated 4 times and were assigned at
random to the different seedbeds. D-D and Edabrom were applied separately
with a hand-operated soil injector at approximately 6 inches deep and 12
inches apart. Agrene was applied by hand in 6-inch furrows spaced at 12
inches apart and mixed into the soil thoroughly with a hand trowel. Dow-
fume MC-2 was applied under plastic sheet cover which was left in place
for 24 hr. After the application of Agrene, D-D, and Edabrom, and the
removal of the plastic sheet cover from the Dowfume MC-2-treated plots, the
seedbeds were watered lightly to prevent excessive escape of the fumigants
Seeding and care of seedbeds. The seedbeds were reworked and wa-
tered lightly 15 days after treatment. Tobacco seeds, var. Viscaya, were
sown at the rate of 1 g per .10 sq m. The seeds allocated to each seedbed
were thoroughly mixed with about 1/4 liter of sieved ash and 2 tablespoon-
fuls each of 50% DDT (WP) and a copper fungicide. The mixture was
broadcast evenly over an entire seedbed and the same procedure was re-
peated until all the seedbeds were seeded. Cheesecloth sheets were used
to cover the seedbeds and to protect them from excessive sunlight and heavy
rains. At about 20 to 25 days after sowing, the cheesecloth sheets were
either removed or adjusted in such a way that the seedlings were gradually
exposed during early morning, late afternoon and night, depending upon
Collection and evaluation of data. Evaluation of treatments was doi
57 days after sowing. Percentage root-knot infection, number of galls p
root system, and seedling height were determined from 50 randomly select
seedlings in each seedbed. Plant height was taken by measuring from tl
base of the stem to the tip of the bud. Density of seedling population
was determined 27 days after sowing in three 625-cm sq sample areas p
treatment plot for all 4 replications.
Nematode populations in the treated beds were determined before ai
after fumigation. Twenty soil cores, 3/4 inch diam and 6 inches lor
were collected at random from the seedbeds. Nematodes were then e
traced from these soil cores using the funnel method as described
Christie and Perry (1951).
Weed population in three 625-cm sq areas per treated bed was deti
mined at 10, 15, and 25 days after soil fumigation for the cyperus speci
and 25 days after treatment for the broadleaf and grass species.
The data gathered were statistically analyzed. The original data on p
centage root-knot nematode infection and population counts that show
high degree of variability, were transformed to angular and square rc
values, respectively, prior to analyses.
RESULTS AND DISCUSSION
Seedling response to soil fumigation. Significant differences in <
gree of infection, number of galls, and height of 50 seedlings were obtain
either between or among treatments (Table 1). Ten weeks after treatme
plots exhibited reduced root knot incidence as compared to the control whi
showed 89.8% infection. D-D, Dowfume MC-2, and Edabrom apprecial
reduced nematode infection among seedlings. Likewise, they also reduce
the number of galls. There was apparently less root-knot nematode
fection among seedlings grown in Agrene-treated seedbeds although infeci
seedlings from this treatment exhibited as many galls as there were
seedlings grown in untreated control seedbeds. Only the seedlings from
Dowfume MC-2-treated seedbeds were statistically taller and more vigor(
TABLE 1. The effect of soil fumigants on root-knot and plant height of 8-week-
cigar filler tobacco var. Viscaya seedlings
Root-knot inci- No. galls per Seedling
Soil Fumigant dence (%)a seedling height (cnr
Agrene 5.73* 6.1 10.5
D-D 7.00** 0.3** 12.9
Edabrom (EDB) 4.30** 0.1** 12.0
Dowfume MC-2 6.20** 0.7** 17.6**
Control 89.80 7.8 10.9
a Statistical differences were determined at 0.05 and 0.01 levels from transform
Significant at 0.05 level.
I ___ T7-,-- XT - - - -
than those in the untreated plots. They were also superior to those in the
other treated seedbeds. Differences in the root system development (Fig. 1)
and stand of seedlings in the chemically treated seedbeds were also noted
Fig. 1. Root systems of cigar filler tobacco
fumigated and non-fumigated (control) seedbeds.
seedlings, var. Viscaya grown in
Fig. 2. Seedling stand and vigor in a D-D-fumigated seedbed.
A numerical decrease in seeding population density was evident in treated
beds but such differences were not statistically significant. Agrene-treated
beds had the least mean number of seedlings per 625-cm sq areas. Those
ited with Edabrom and Dowfume MC-2 had the most number of seed-
TIL ,^ .I -'ex^>;-r. -C, ..i->: S -'
FUCCoU SbCUUUS. aill LIIC g iCIlladLsLIUCs upIaitoLLdIy appJlcsCbbu LIC reClimeLL t-
n of broad leaf and grass weed species up to 25 days after soil treatment
'able 3). Significant reductions in cyperus weed growth was also observed
BLE 3. he effect of soil fumigants on weed species growing in tobacco seedbeds,
25 days after treatment
Mean number of weeds
Cyperus Broad leaf Grass
rene 3.8 11.9** 83.5**
D 12.6 11.5** 111.7
abrom (EDB) 4.9 4.2** 66.3**
wfume MC-2 1.2** 2.8** 20.8**
patrol 4.4 19.6 98.4
in the different treatment beds up' to 25 days after soil fumigation (Table
4). Of the 4 treatments, only Dowfume MC-2 controlled weeds for longer
period as shown by the statistically fewer cyperus weeds on the 25th day after
treatment. The rest effectively controlled the weeds up to 15 days only.
TABLE 4. Cyperus weed count on cigar filler tobacco seedbed at indicated number
of days after soil fumigation
Number of cyperus weeds
10 days 15 days 25 days
Agrene 2.5** 2.4** 3.8
D-D 0.9** 0.7** 12.6
Edabrom (EDB) 0.2** 0.2** 4.9
Dowfume MC-2 0.0** 0.0** 1.2**
Control 5.6 6.5 4.4
HSD (Days) 0.05 = 0.7
HSD (Treatment) 0.05 = 0.8, 0.01 = 0.9
This study demonstrated the value of soil fumigation in cigar filler to-
bacco seedbeds. With the use of nematocides, the adverse effects of nema-
todes on tobacco seedlings was substantially reduced. Furthermore, added
protection from weeds was indicated. The results also indicated the accele-
ration of seedling development due to the reduction of nematode popula-
CHRISTIE, J. R. & V. G. PERRY. 1951. Removing nematodes from soil. Proc. Helmin-
thol. Soc. Wash. 18: 106-108.
GRAHAM, T. W. 1956. Weed and root-knot control in tobacco plant beds by surface
drench and other treatments. Plant Dis. Reptr. 40: 1041-1044.
HURTADO, E. A., H. R. PASCUA, B. A. ESTRADA, & A. M. MANLONGAT. 1966. Control of
tobacco nematodes at the seedbed. Philippine Tobacco Rev. 3 (1) 8-10.
MILNE, D. C. 1962. Chemical control of nematodes in tobacco seedbeds and lands.
Tobacco Abstr. 7: 1 (Abstr.)
MITKOVSKI, J. 1960. Application of viapam for disinfection of the soil in tobacco
seedbeds. Tobacco Abstr. 5: 1 (Abstr.)
PASCUA, H. R. & B. A. ESTRADA. 1966. Efficacy of Geigy (Agrene) nematocide at
different concentrations for the control of root-knot nematodes. Ann. Rept. Phil-
ippine Tobacco Administration, C.T.E.S. Fiscal Year 1965.66.
KI A UT'I'I UiN UV r U ir r rnj liN i v jJ ri, rt.-i. J .' J- J .,, .*W ,.
TO INFECTION BY MELOIDOGYNE JAVANICA
R. T. TOLEDO AND R. G. DAVIDE
Former undergraduate thesis student, and Assistant Professor, respectively, Depart
ment of Plant Pathology, U.P. College of Agriculture, College, Laguna, Philippine
Accepted for publication 25 November 1969.
Several vegetable and field crops were found susceptible to Meloidogyne
favanica (Treub.) Chitwood. The susceptible field crops were tobacco, jute,
kadios, mungo, and tapilan; the resistant ones were cotton, corn, soybean,
kenaf, sorghum, wheat, peanut, centrosema, kudzu, and rice. The total
absence of root galls in cotton indicated its high degree of resistance.
Among the susceptible vegetable crops were okra, tomato, squash,
patola, batao, cowpea, cantaloupe, pechay, eggplant, bush lima, cucumber,
upo, bush sitao, mustard, pepper, lettuce, ampalaya, garlic, cauliflower,
Cabbage, and watermelon. Sweet potato, radish, onion, and potato showed
resistance to the nematode.
There was a higher rate of nematode development and reproduction
in the susceptible than in the resistant crops. Root system of severely
infected crops were badly damaged by the nematode. Severe nematode
infection stunted the susceptible plants.
Meloidogyne javanica (Treub.) Chitwood, is one of the root-knot nem;
tode species that attacks a number of field and vegetable crops. Although
not as widely distributed as M. incognita, this species is potentially de
tructive to several economic crops in the Philippines. Recently, Cortad
and Davide (1968) have shown that M. javanica can severely attack tobacco
Likewise, Valdez (1968) observed that this species is capable of attacking
Cucumis melo, Cucurbita maxima, Lycopersicon esculentum, Celosia argei
tia, Gynura crecidioides, Momordica charantia, Luffa cylindrica, Hibisct
sabdariffa, and Ageratum conyzoides.
Investigations abroad showed that M. javanica has a wide suscept rang
It attacks several varieties of vegetable, field, forage, and fruit crops (Sasse
and Winstead, 1956; Whitehead and Kariuki, 1960; Calitz and Milne, 196!
Balasubramanian and Rangasuani, 1964; Swamy and Govindu, 1966; Mintc
et al., 1967). In the Philippines, the suscept range of M. javanica has ni
yet been thoroughly established. Knowledge of the range of suscepts I
this nematode is essential in formulating control measures through crc
rotation or use of resistant crop varieties.
1ius suUay was primarily inltatea to determine wnicn ot our tleli ana
vegetable crops are resistant or susceptible to M. javanica.
MATERIALS AND METHODS
Preparation of inoculum. The pure culture of M. javanica was derived
rom a single larva isolated from tobacco. The nematode population was
n/'r- -i a n -- +- --rr1 .t-i/i f:j-w* -1- -j.i iVlrim 1 r] >l -.J **-. C-.-wrrr ]
juash Native Cucurbita maxima L.
nion Native Allium cepa var. ascolonicum L. A. sativum L
TOLEDO & DAVIDE: MELOIDOGYNE
Common Name Variety Scientific Name
Cauliflower Brassica oleracea var. botrytes L.
Bush lima White Phaseolus lunatus L.
Cucumber No pickling Cucumis sativus L.
Watermelon -Citruelus vulgarisa Schrad
Cabbage Copenhagen Brassica oleracea var. capitata L.
Sweet potato B.N.A.S. Ipomoea batatas (L.) Potr.
Patola Native Luffa cylindrica Standl.
Upo Native Lagenaria siceraria Standl.
Batao Dolichos lablab L.
Potato Baguio Solanum tuberosum L.
Lettuce Chinese Lactuca sativa L.
Cowpea Variety No. 4 Vigna sinensis (L.) Say.
Seeds of these different field and vegetable crops were obtained from
the UPCA Department of Agronomy, and the BPI Economic Garden, Los
Bafios, Laguna. They were germinated in 6- or 8-inch diam clay pots filled
with disinfested sandy loam soil. Later, the seedlings were thinned to 4
per pot. For each crop, 3 replicate pots with 4 plants each were provided.
Each pot was then inoculated with 50 egg masses of M. javanica. A cor-
responding number of pots with the same number of plants were not inocu-
lated and maintained as control. The pots of experimental and control
plants were placed atop inverted clay pots and spaced far apart in the
greenhouse to avoid contamination.
Evaluation of the pathologic reaction of the different crops to nema-
tode infection was made 2 months after inoculation. Root systems of the
test plants were carefully removed from the pots and washed with running
water to separate the adhering soil particles and debris. The degree of
nematode infection on these crops was rated by gall index of I for no gall,
2 for trace, 3 for slight, 4 for moderate, and 5 for severe galling.
Nematode development in the host tissue. The behavior of the nema-
todes in the various crops was determined by their population development
and rate of reproduction in each crop. One gram of galled roots was taken
from each test plant. The infected roots were fixed in FAA (15 ml 95%'
ethyl alcohol, 1 ml glacial acetic acid, 6 ml formalin in 40 ml water) for
at least 48 hr. Roots thus treated were washed with tap water for 5 min
and stained in boiling acid-fuchsin lactophenol for 2 to 3 min. The stained
roots were rinsed with tap water to remove excess stain. They were stored
in clear lactophenol for about 1 week. The galled roots were dissected and
examined under a binocular microscope and the nematodes were picked up
and mounted in ringed glass slides. The nematodes were classified and
counted according to sex developmental stages described by Triantaphyllou
and Hirschmann (1960).
RESULTS AND DISCUSSION
Pathogenicity test. The different test crops varied in pathologic re-
action to M. javanica infection (Fig 1). Plants that showed gall index of
Nos. 1 & 2]
1 to 2 were considered resistant and those rated 3, 4, and 5 gall index were
considered susceptible. On this basis, 10 field and 4 vegetable crops were
found resistant while 5 field and 21 vegetable crops were found susceptible.
Fig. 1. Pathologic responses (A) of indicated crops to Meloidogyne javanica and
the corresponding root systems (B) of uninoculated plants.
T nn r -AV. TAITnV Mvi rninor.vNF
TABLE 2. Number and developmental stages of Meloidogyne jacanica in 1 g rool
sample of each crop, 2 months after inoculation
undif- larval stages Adults Larval stages Total
tiated 2nd 3rd-4th No With 2nd 3rd-4th Adults
Corn 26 22 -48
Wheat 12 1 3 1 3 20
Sorghum 7 10
Peanut 8 2 10
Soybean 31 2 6 1 23 -- 3 66
Mungo 159 41 36 26 88 48 24 4 426
Tapilan 855 26 25 24 87 25 17 5 1064
Centrosema 12 4 16
Kadios 1276 16 6 15 477 17 10 19 1836
Cucumber 791 19 38 20 269 16 27 11 1191
Watermelon 399 6 8 2 187 7 11 2 586
Cabbage 467 23 31 46 237 12 26 8 850
Sweet potato 38 3 5 8 16 3 6 79
Patola 891 58 83 121 506 27 60 31 1777
Upo 198 5 16 19 361 3 7 3 612
Batao 1567 14 15 11 175 7 9 3 1801
Potato 26 6 13 8 18 3 6 1 81
Cowpea 971 41 60 56 486 19 33 12 1681
Nos. 1 &8 2
'he susceptible field crops that showed galling index of 3 to 5 were mungo,
ipilan, kadios, jute, and tobacco. The field crops where no gall was ob-
rved and regarded as resistant were sorghum, wheat, peanut, centrosema.
udzu, cotton, and rice. Other resistant field crops on which trace galling
as observed were corn, kenaf, and soybean.
LLASUBRAMANIAN, M., & G. RANCASUANI. 1964. Studies on host range and histo-
pathology of root-knot infections by Meloidogyne javanica. Indian Phytopathol.
LLITZ, P. C., & L. D. MILNE. 1962. Reaction of Nicotiana species and species
crosses to the root-knot nematode Meloidogyne javanica. South African Agri.
Sci. 5: 123-126.
)RTADO, R. V., & R. G. DAVIDE. 1968. Survey, identification and pathogenicity tests
of nematodes associated with tobacco grown in Cagayan Valley and Ilocos region.
Philippine Agr. 51: 779-801.
ENTON, N. A., I. FORBES, & H. D. WELLS. 1967. Susceptibility of potential forage
legumes to Meloidogyne species. Plant Dis. Reptr. 51: 1001-1004.
SSER, J. N. & N. N. WINSTEAD. 1956. Reaction of cucumber varieties to five
root-knot nematodes (Meloidogyne sp.). Plant Dis. Reptr. 40: 272-276.
'AMY, B. C. N., & H. C. GOVINDU. 1966. A preliminary note in the plant parasite
nematodes of the Mysore State. Indian Phytopathol. 19: 239-240.
Jos. 1 & 2]
TOLEDO & DAVIDE: MELOIDOGYNE
'RIANTAPHYLLOU, A. C. & N. HIRSCHMANN. 1960. Post-infection development ot Me-
loidogyne incognita Chitwood, 1949 (Nematoda; Heteroderidae). Ann. Inst. Phy-
topathol. Benaki, n.s. 3: 1-11.
ALDEZ, R. B. 1968. Survey, identification, and host-parasite relationships of root-knot
nematodes (Meloidogyne sp.) occurring in some parts of the Philippines. Philip-
pine Agr. 51: 802-824.
VHITEHEAD. A. G., & L. KARIUKI. 1960. Root-knot nematodes surveyed in cultivated
areas in East Africa. East African Agr. J. 26: 87-91.
GREENHOUSE TEST FOR CONTROLLING MUNG BEAN POWDERY
MILDEW BY INCORPORATING CHEMICAL IN SOIL
F. C. QUEBRAL
Assistant Professor, Department of Plant Pathology, UPCA, College, Laguna E-109.
Accepted for publication 8 October 1969.
Du Pont experimental fungicide 1991 [1-(butylcarbamoyl)-2-benzimida-
zole carbamic acid, methyl ester], when incorporated into 400 cm3 soil at
the rate of 0.5, 0.25, 0.15, and 0.07 g 50% active ingredient formulation,
showed systemic activity in mung bean (Phaseolus aureus Roxb.) against
powdery mildew. The different rates gave protection to the plants through-
out the experiment. The test chemical was not phytotoxic. Based on results
of this greenhouse test, F-1991 should be further tested in the field for the
control of mung bean powdery mildew.
A lot of approximately 3,500 sq m at the UPCA Central Experiment
Station, planted to mung bean (Phaseolus aureus Roxb.) var. CES 14 in
October 1968, was observed severely affected by powdery mildew caused by
Erysiphe polygoni DC at flowering and early fruiting stages. Every plant
was infected such that from a distance, the whole field looked as though
it was intentionally dusted with white powder. Infected leaves prematurely
turned brown and became blighted even before the pods were completely
mature. In an estimate by the UPCA agronomists, harvest from such variety
would normally give an average yield of 1 to 1.5 tons of clean seed per
hectare. But in this particular planting, only 800 kg clean seed per hec-
tare was obtained. This indicated that an epiphytotic outbreak of powdery
mildew can quantitatively reduce yield of mung bean.
When Du Pont experimental fungicide 1991 [1-(butylcarbamoyl-2-benzimi-
dazole carbamic acid, methyl ester] was earlier tested in the Philippines, it
was found effective against powdery mildew of cucumber and leaf mold of
tomato, as a foliar spray (Baniqued, Isidro, and Domingo, 1968; Quebral
and Villareal, 1968). Because it has also been claimed that this fungicide
has a systemic activity when taken in by plants from the soil (Hammett.
1968; Ryker, 1967), it was thought that it may be more effective in protect-
ing plant from external invasion when applied to the soil and possibly more
economical than spray application. This paper presents evidence of sys-
temic activity of this fungicide against powdery mildew of mung bean.
QUEBRAL: MUNG BEAN POWDERY MILDEW
MATERIALS AND METHODS
The approach to this work was similar to that reported by Hammett
(1968) but the only difference was that mung bean (Phaseolus aureus Roxb.)
var. CES 14 was used as test plant. Four hundred cm3 of sand-clay loam
soil mixture in 4-inch clay pots was used as rooting medium. Two pots
were used per treatment and 10 seeds were germinated per pot. Fungicide
1991, 50% active ingredient formulation, was thoroughly mixed with the
rooting medium at the rate of 0.5, 0.25, 0.15, and 0.07 g. Two trials were
carried out. In the first trial, the experimental and control lots were irrigated
by placing the potted plants in pans containing water maintained at a
desired level. In the second trial, the potted plants were placed on a shallow
cement greenhouse bench flooded with water at a desired level. The test plants
were exposed to natural inoculation by surrounding them with severely mil-
dewed mung bean plants as source of inoctlum. Disease assessment was
made visually according to a standard diagram (Fig. 1).
DIAGRAM SHOWING APPEARANCE OF MILDEW
PUSTULES ON THE LEAVES EXPRESSED AS
PIICKNT OF THE LEAF AREA
WC, u- y\ /^., -
Is." "j *, ; *..
S. I PUISTU LEa 05 cM' A ERAGE LEAM ARMEA.8
Fig. 1. Rating index used in assessing severity of mung bean powdery mildew.
RESULTS AND DISCUSSION
Fungicide 1991, when incorporated into the soil, was taken up by the
roots of mung bean seedlings thus providing complete protection against
powdery mildew during the duration of the experiment in each trial. Con-
trol plants started dying 35 days from sowing in each trial. The cotyledonary
leaves of the control plants were readily infected 7 days after sowing. The
Nos. 1 &: 2]
their growth was seriously impaired as they were rapidly defoliated (Fig.
Plants' grown in the treated soil remained free from mildew for 70 day,
observation. No phytotoxicity was noted at any concentration tested.
Fig. 2. Effect of high and low concentrations of Fungicide 1991 on severity of n
bean powdery mildew.
The efficacy of Fungicide 1991 as a systemic compound has show
potential promise in controlling mung bean powdery mildew. On the b
of this test, field trial with Fungicide 1991 applied in the rows and r
tilled at the time of planting is suggested.
N INVESTIGATION OF THE CAUSE OF THE "TAPUROK"
DISEASEE OF COOKING BANANA IN NEGROS ORIENTAL
ELDON I. ZEHR AND R. G. DAVIDE
Graduate Assistant, Department of Plant Pathology, Cornell University, and
tant Professor, Department of Plant Pathology, UPCA, College, Laguna. The
r author's present address is Department of Plant Pathology and Physiology,
son University, Clemson, South Carolina 29631.
This investigation was supported by Ford Foundation funds under the U.P.-Cornell
uate Education Program.
The writers acknowledge the generous assistance of Mr. J. V. Tale, Provincial
:ulturists, and Mr. Isaac Larot, Field Representative for Negros Oriental, Agri-
ral Productivity Commission.
Accepted for publication 14 November 1969.
Symptoms, occurrence, and cause of the "tapurok" disease of cooking
banana in Negros Oriental were investigated. The isolation of bacteria
from diseased plants and results of patohgenicity tests indicated that the
malady is caused by an unidentified bacterium. The pathogen is probably
not a strain of Pseudomonas solanacearum E. F. Sm.
The "tapurok" disease of cooking banana (Musa paradisiaca L.) came
he writers' attention while visiting near Dumaguete City, Negros Oriental,
January 1968. According to residents of the area, the disease has been
ent in the province for many years, but its cause and control have not
I investigated. This paper reports investigations into the cause of the
ase and its distribution in Negros Oriental.
MATERIALS AND METHODS
Description of disease symptoms was based on examination of 15 to 20
cted plants near Valencia, about 10 km from Dumaguete City, Negros
A Fusarium sp. isolated from an infected plant was cultured on PDA
Q2 C. Spores from 6-day cultures were suspended in 25 ml sterile dis-
d water. Bacteria from infected plants were grown on nutrient agar
is for 48 hr at 32 C and suspended in 20 ml sterile distilled water.
Immature fruits of 16 young cooking banana plants (cv. 'Saba') were
:ulated with the bacterial or fungus spore suspensions, using a 2-cc
syringe and 3/4-inch, 24-gauge hypodermic needle. Male flowers were aton
inoculated with the Fusarium spore suspension, but not with the bact
suspension. Young tomato plants (Lycopersicon esculentum Mill. cv. '
globe,' and young diploid banana plants (Musa balbisiana Colla cv. 'Butt
15 to 20 cm tall, were stem-inoculated with suspension of bacteria in st
distilled water. Uninoculated plants were maintained as checks.
Disease symptoms. Symptom expression of infected plants was restricted
he inflorescence, axis, fruit, and aerial stem. Infected fruits had normal
rnal appearance but numerous granular, yellow, hard pockets of tissue
! scattered throughout the pulp, accompanied by reddish-brown or yel-
.sh-brown discoloration of the central portion of the fruit (Fig. 1). This
coloration was continuous in the vascular bundles from the fruit into
axis and aerial stem and sometimes it extended into the corm. Paren-
na cells surrounding the discolored vascular bundles were brown and
Affected plants had few external symptoms and, unless the male in-
escence was present, they could not be differentiated from healthy plants.
cts covering the male flowers were normal moist and compact until
Dropped but bracts of infected inflorescences were dry and loose, and
r abscission was delayed (Fig. 2). Male flowers were blackened and
rotic and the inflorescence appeared dry and ragged.
Fig. 2. Normal inflorescence of Saba cooking banana (A) and inflorescence of
it with tapurok disease (B). Note delayed abscission of bracts and ragged ap-
*ance of the diseased inflorescence.
Disease distribution. The tapurok disease was uncommon in the im-
liate vicinity of Dumaguete City and in other areas near the seacoast
was common in the higher elevations nearby. At Valencia, about 1500
above sea level and 10 km from Dumaguete City, more than 50% of
TTT TVPPNTFM I
Productivity Commission Field Representative, Mr. Isaac Larot, up to
infection is known to occur. The disease is considered a limiting
for cooking banana production in Negros Oriental.
Pathogenicity tests. A bacterium was always isolated from d
fruits and portions of the inflorescences axis, and aerial stem, but some
Fusarium sp. was also isolated.
Fig. 3. Longitudinal section of immature fruit of Saba cooking banana in,
one month earlier with bacteria associated with the tapurok disease. Note d
central portion of the inoculated fruit.
Inoculations with the consistently isolated bacterium were made
planting of 'Saba' cooking banana at the Agricultural Productivity
mission Experiment Station near Dumaguete City. One month after
lation, typically diagnostic symptoms developed in the young fruits inoi
with the bacterial suspension (Fig. 3). The bacterium was reisolatec
On tetrazolium medium (Kelman, 1954), the bacterium produced
round, convex colonies, 1 to 2 mm diam, with pink centers and whit
gins. Colonies resembled those of the "SFR" (small, fluidal, round)
of Pseudomonas solanacearum E. F. Smith (Buddenhagen and Kelman.
irnt. ''1'a flhflfTZ' flt- (Vnnu TN
toms produced by our isolate resembled those of the banana disease
I by this strain (Buddenhagen and Elsasser, 1962). To test whether
acterium in question was P. solanacearum, 8 Marglobe tomato plants
diploid banana plants were inoculated at the stem with a suspension
test bacterium. But none of the inoculated plants wilted or developed
ar browning characteristically caused by P. solanacearum.
,ased on results of pathogenicity tests, the tapurok disease of cooking
la probably is caused by a bacterium. Although the bacterium was
lentified, it probably is not a strain of P. solanacearum because it did
ause wilt of diploid bananas or tomatoes. Furthermore, no bacterial
was observed in diseased cooking banana and infected fruits did not
SAlthough the tapurok organism has some systemic activity in bana-
does not affect the entire plant as does P. solanacearum (Budden-
and Elsasser, 1962).
Similar disease called "bugtok" occurs in Mindanao (Roperos, 1965).
toms of "bugtok" as observed near Davao City in Mindanao were
similar to those of tapurok, except that the discoloration of the fruit
)lack, whereas yellowish-brown or reddish-brown discoloration is typical
purok. According to Roperos (1965), bacteria are also associated with
-he continuous vascular browning from the fruit into the axis and
stem suggests that the pathogen may invade banana through the
e flowers, and perhaps, through the male inflorescences as well. But
node of ingress and pathway of infection was not investigated.
NHAGEN, I. W. & T. A. ELSASSER. 1962. An insect-spread bacterial wilt epiphy-
tic of Bluggoe banana. Nature 194: 164-165.
NHAGEN, I. W. & A. KELMAN. 1964. Biological and physiological aspects of
acterial wilt caused by Pseudomonas solanacearum. Ann. Rev. Phytopathol. 2:
kN, A. 1954. The relationship of pathogenicity of Pseudomonas solanacearum
) colony appearance in a tetrazolium medium. Phytopathology 44: 693-695.
os, N. I. 1965. Note on the occurrence of a new disease on cooking banana
i the Philippines. Coffee and Cacao J. 8: 135-136.
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