JOURNAL OF .
THE PHILIPPINE PHYTOPATHOLOGICAL SOCIETY .
tracts of Papers Accepted for Presentation ., f:.
at the Second Annual Meeting of the .
Philippine Phytopathological Society,
College, Laguna, April 10, 11, 1965 .................. ... . .
Ilular Slime Molds from '
Philippine Soil ........................................ 4..
1. J. Dogma, Jr. and R. C. Blanicaver'
dress, Dr. George A. Zentmyer, President-
elect, American Phytopathological
Society ..................... ......... ...................... 53::'i'
TFM PHILIPPINE PHYTOPATH040GICAL SOCIETY
Founded on October 10, 1962
The P. P. 9. Council
President, OFELIO R. EXCONDE, University of the Philippines, College, Laguna
ice esident, HIPOLITO -Pr CUSTODIO, Bureau of Plant Industry, San An-
Secretary, MA, SALOME E. DEL ROSARIO, University of the Philippines, College,
"Treasurer, PRISCILLA T. CHINTE, International Rice Research Institute, Los
Retirm* g 'President, BERNARDO S. CASTILLO, Bureau of Plant Industry, Region
No. 1, Dagupan City, Pangasinan
VICTORIA M. ELA, University of the Philippines, College, Laguna
LUCIO N. GIE, Bacolod City (Visayas)
ALFREDO L. ELOJA, Bureau of Plant Industry, Davao Experiment Station,
Davao City (Mindanao)
Official, Organ of the Philippine Phytopathologocal Society
EMMIANO F. ROLDAN, Editor-in-Chief, Araneta University, Victoneta Park, Rizat
MARTIN S. CELINO, Philippine.. Coconut Administration, Diliman, Quezon City
JOSE R. DEANON JR., University of the 'Philippines, College, Laguna
AUR-EO L. MARTINEZ, Bureau of zPlant Industry, Lipa City
BERNARDO P. GABRIEL. University of the Philippines, College, "guna,
E. LOPEZ, Philippine Sugar Institute, Los Bahos, Laguna
Business Management -4
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ABSTRACTS OF PAPERS ACCEPTED FOR PRESENTATION
AT THE SECOND ANNUAL MEETING OF THE PHILIPPINE
PHYTOPATHOLOGICAL SOCIETY, College, Laguna
April 10, 11, 1965
Physiologic races of Piricularia orvzae Cav. in the Philippines.-
J. M. Bandong and S. H. Ou. One hundred monosporial isolates of
Piricularia oryzae isolated from rice specimens collected from
various regions of the Philippines were inoculated to 3 sets of
differentials from the United States. Japan and Taiwan totalling
to 38 varieties. In addition, inoculations were made also to 22
common varieties from Southeast Asia and the United States. Va-
rietal reactions were recorded as resistant (R), intermediate (M),
and susceptible (S).
Based on the reactions of the United States, Japanese and
Taiwan sets of differentials, the 100 isolates were classified into
23. 29. and 30 pathogenic races. None of the 3 sets of differential
varieties were satisfactory for use in the Philippines.
Twelve varieties were selected as tentative differentials for use
in the Philippines. Using this set of differentials, the isolates were
classified into 26 pathogenic races. Races P-9, P-11, P-13, and P-21
were commonly found in Luzon; P-18 in eastern Visayas, and P-25
in western Visavas.
Races 3, 5, 6, 10. 11, and 16, identified by workers in the U.S.,
are present in the Philippines. Only race T2 of Japan and race 6
of Taiwan were found in the Philippines.
Twelve varieties tested were found resistant to most of the
races of P. oryzae. Kataktara DA-2 and Taichung 181 were resistant
to all of the races.
Association of Thielaviopsis paradox with root rot of coco-
nut.-C. A. Calica, C. A. Baniqued and P. F. Ventura. An investi-
gation of the fungi associated with the roots of cadang-cadang-in-
fected trees was undertaken at the Central Experiment Station by
the Bureau of Plant Industry in Manila. Thielaviopsis paradoxa
Wetn. was among a number of fungi isolated from infected roots.
The organism was isolated from root samples obtained in the Bi-
col area and in some parts of Laguna (Alaminos and San Pablo
Pathogenicity tests conducted with T. paradoxa revealed that
organism incited root rot on potted two-year-old coconut seed-
I-iiELri-IN ri-fl i lUrAI i-u.
lings. Rotting commenced at the tip and progressed toward tnf
base of the root. Generally, the feeder roots were involved, al
though tip of main roots might also be affected. The production
of white roots was almost wholly inhibited by the organisms. Thi
affected portion of white roots assumed a brown color, was hydrc
tic with a distinct brown margin which delimited it from the un
infected area. Root rot manifested itself in the roots from twelve
to fifteen days following the application of spore suspension t(
the soil around the base of the seedling.
No foliar symptoms were apparent on the infected plant ex
cept a slight nallor of the older leaves and flaccidity of the young
est unfurled leaf.
Mechanical transmission of abaca mosaic virus and some o
its physcial properties. D. A. Benigno and Ma. Salome del Rose
rio. The addition of chemicals, (1 per cent caffeine; 20 per cen
sucrose; 3 per cent dibasic potassium phosphate) to the inoculun
beforeor during maceration of the leaves, facilitated sap transmis
sion of the abaca mosaic virus (AMV).
Physical properties of AMV were studied on corn seedlings
The virus withstood heating at 480C for 10 minutes, aging in vitr<
and in vivo for 1 day and 45 days, respectively, and was still infec
tious at 10.2 dilutions.
The plants, Nicotiana glutinosa L., Datura stramonium L., Cht
nopodium amaranticolor L., Phaseolus vulgaris L., var. Bountiful
Vigna sinensis (L,.) Endl. var. cowpea No. 6, and Cucumis sativu
L. var. National Pickling were not infected when inoculated wit]
the abaca mosaic virus despite the fact that these plants are knowI
to be local-lesion hosts to a number of plant viruses.
Studies on insect transmission of Tristeza virus in the Philip
pines.- C. S. Celino, D. R. Panaligan and U. V. Molino. Nine in
sects were tested as vectors of the tristeza virus in the Philip
pines, namely: Toxoptera citricidus (Kirk.), T. aurantii (B. d,
Fonsc.), Aphis gossypii Glover, Ferrisiana virgata (Ckll.), Pseudc
coccus sp. nr. filamentosus, Pseudococcus citriculus Green, Dia
pherina citri Kuway., Coccus viridis (Green) and Hystereneura se
tariae (Thomas). Insects were collected from time to time in thi
field and prior to inoculation they were first made to feed on health
citrn's seedlings for about 5 days inside the greenhouse before al
lowing them to feed on the virus source. Key (Mexican, West In
dian) lime seedlings that were previously infected with tristeza b3
budding were maintained as sources of virus for insect transmis
sion studies. Three of these species of insects successfully trans
mitted the virus. They are Toxoptera citricidus, T. aurantii anc
Aphis gossypii which all belong in the aphid group. The symp
toms produced on key lime seedlings infected by the three aphic
ctors in these studies showed vein clearing, chlorosis, cupping
the leaves and stunting. Stem pitting was also produced in the
Eusebio and C. C. Banatin. Schizophyllum commune Fr., a vei
common gill fungus, was generally regarded as harmless and si
perficial on wood and other forest products.
Results showed that the optimum temperature for growth c
S. commune was 320C, which was considerably higher as cor
pared to some wood-attacking Hymenomycetes. The minimum
moisture content that permitted growth in balobo (Diplodisct
paniculatus Turcz.) was 24 per cent based on over dry weigh
development was inhibited at 20 per cent. The wood-decaying c;
pacity of S. commune in two months was lower than that of Porn
sp., a common wood rotter. The former, however, showed a high
decaying capacity in the first month. The fungus showed negative
reaction on gallic acid and positive reaction on tannic acid. Th
optimum pH range for the fungus to grow was between pH 5.1
and 6.47. S. commune showed more tolerance to sodium fluorid
zinc chloride, copper sulfate, and sodium chromate but not to coa
ta; creosote. It appeared to be very sensitive to sodium pentachlc
rophenate (Dowicide G), sodium arsenate, pentachlorophenol. coi
tate, light brown to dark brown. Conidiophores are arranged single:
or in group; average size, 139.8 x 11 microns. Conida are pal,
hr'un tn rlrl Ar mrnurn A-10 c~ntatp ctraiOhct nr r'irvedp wibdat n1
ranosan M, Acialone iiram, iermate, uelsan A-L, ranoram /a,
ancide Z-65, Arasan SFX, Panoram D-31, and Tersan 75 were
)und to be promising.
Further studies on spraying insecticides and cover cropping
n the control of abaca mosaic.--M. R. Gavarra, F. R. Celebrar
nd A. L. Eloja. Insecticide spraying failed to minimize the rate
F spread of abaca mosaic. No significant difference, in the per-
ntage mosaic infections was noted between sprayed and un-
?rayed plots. Similarly, spraying did not succeed in reducing the
umber of aphid trap catches. More aphids were found in trans
)cated in the treated than in the untreated plots although the dif-
erence was far from being significant. Among the three methods
F culture, clean treatment had the highest occurrence of mosaic
ifections compared to either covercropping or ordinary treatment.
igh incidence of the disease in the clean culture was reflected by
greater number of alate aphids caught in the yellow water traps
during a period of three months trapping.
Significant reduction in mosaic infection was attributed to the
.ltural practices of regular indexing for disease infections and
ibsequent roguing of all infected abaca stools. This practice was
opted not only in the experimental area but also in adjoining
baca plantations of the Davao Experiment Station to reduce both
eternal and external sources of the disease.
Etiology of root rot of rice. -D. B. Lapis, and 0. R. Excond(
Root rot, a persistent and destructive disease of rice plants, wa
observed in some ricefields in the provinces of Laguna, Bulacal
and Pangasinan. Isolations made from rotted roots consistently
Fitz., Fusarium moniliforme Sheldon emend. Snyder
and Sclerotium oryzae Catt. Inoculations with th
iced symptoms on the leaves and on the roots. Foli,
were characterized by yellowing, salmoning, dryin
Snrl ItPf chanpthb anrl PeviPntIal dlath nf thP nInnt. 7
oaii iLiUUCU allu palllullg UI iJCtaSLdaL varietieS I1Ke ijere m2
BPI-76, Peta, Milfor 6(2), Miltex 125, Sinantonio, Norilon Stra
340, Dud Kuning, O Benton (nb), Century 52, O Benton (b), Tex
331, Ac 2246, and Buenketan are the suggested control measures
tops.--A. L. Martinez and B. S. Castillo. We have previously re
Symptoms ot seecdlim yellows sucn as missnapen or alstortea leaves
reverse cupping, yellowing and stunting of the test plants inocu
lated from all the trees were observed after 3 to 4 weeks. The re
ULJ I(1H IC L uiCu GllU calou *aULU IL11" L o .
susceptible varieties while the downward movement was limited<
to 1-2 cm. from the point of inoculation on resistant varieties. 0
boratory. Seven gave complete inhibition of conidia after 24 to
hours of incubation. Ten gave germination of conidia as low
age of 83.1 per cent. On the basis of the results obtained fror
the slide-germination test, 35 fungicides were tested at 3 rates fc
their phytotoxic effect to corn plants. Results showed that 24 fur
gicides were not phytotoxic even at the highest dose used. Eigli
were phytotoxic at the highest dose and 3 were toxic at all dose:
Several plantings of susceptible variety made in the seedbed an
in the field did not get a fairly good infection to warrant sprayin
with the promising fungicides and to assess their value in control
ling the disease.
Reaction of world collections of rice varieties to rice blast.-
S. H. Ou and F. L. Nuque. Using upland, short row method fo
testing blast resistance. 8,214 rice varieties of the world collection
have been screened at the blast nursery of the Institute in the pas
three years. A standard scale of 1 to 7 was used for classifying th
degree of resistance, 1 being the most resistant and 7, the mos
Of the 8,214 varieties, 1,456 appeared resistant (1 to 2 reac
tion) to the disease from the preliminary tests. When these re
sistant varieties were retested at different seasons, about 700 wer
rated as highly resistant. There appeared a shift prevailing race
in the nursery.
The above results indicated that there were plenty of resistan
materials for breeding resistant varieties, believed to be the basic
approach to control the disease.
In several tests for resistance to blast, both japonica and in
dica type varieties were included. The results revealed that th
former tyne appeared to be more resistant to blast at Los Bafioi
than the latter. When the reactions of some japonica and indices
varieties at Los Bafios were compared with the reaction in Taiwar
and Japan, the results showed that these japonica varieties wen
more susceptible in these countries while indica varieties wer
susceptible in the Philippines.
Host-range and symptoms of two virus isolates from Croto
laria saltiana Andr. and Cassia occidentalis Linn.- O. R. Paguic
and Ma. Salome del Rosario. Mosaic-infected Cassia occidental:
Linn. and Crotolaria saltiana Andr. plants were collected in som<
coconut plantations, along the road sides of Laguna and Quezor
provinces. The virus isolated from these hosts were studied for
their svmptomatologv. host range, modes of transmission and cer-
tain physical properties.
Both Cassia and Crotolaria isolates (COMV and CSMV) were
found to be transmitted mechanically by sap with the aid of ab-
rasive and 1 per cent neutral potassium phosphate. The viruses
were not carried through the seed. Their host-range were restricted
certain species of the Leguminosae and Chenopodiaceae, the lat-
!r being a local lesion host.
Studies on the physical properties of COMV and CSMV re-
ealed that they could not withstand dilution beyond 1:10,000 and
:2000. The thermal inactivation points were 650 and 750C for 10
minutes exposure;. and longevity in vitro were 17 days and 3 days
Room temperature and 2 and 1 week at freezing temperature,
Purification and electron microscopy of abaca mosaic virus.-
.K. Palomar, Ma. Salome del Rosario and J. Melgar. Abaca mo-
tic virus (AMV) was investigated for its possible identification
trough purification and electron microscopy.
By adding one per cent caffeine, AMV was sap-transmitted from
baca to corn with ease. Chenopodium amaranticolor Coste and
eyne., Datura stramonium L., Gomphrena globosa L., Nicandra
hysalodes (L.) Pers., Nicotiana glutinosa L., and Trifolium re-
ens L. were found not infected with crude and purified sap of
Based on infectivity tests, the use of either one per cent ben-
mite or ascorbic acid-egg albumin was found to be the best among
ke methods used in the purification. Suspensions of the purified
product were clear, highly infectious and composed of long, flexous
The morphology of AMV resembled that of the sugarcane mo-
tic virus, while its physical properties approached those of the
Effect of dipping rice seedlings in fungicidal solutions on the
control of rice blast.- S. A. Raymundo, O. R. Exconde and R. S.
ecesario. .Seven fungicides were tested as dipping solutions for
ce seedlings to determine their protective ana eraclcative values.
he seedlings (var. Tejre mas) were grown in seedboxes. When the
;edlings were at the 2-leaf stage, they were uprooted and then
pped into the different fungicidal solutions. Three doses and 6
ngths of dipping were tested for each fungicide. Evaluation of
te efficacy of the fungicides was based from the lesion counts
id percentage of infected leaves, 20 days after inoculation.
The results of this study showed that out of 7 fungicides
sted, 6 were effective as protectarts and 3 as eradicants. In the
mt-\+>/-> t-yt + f f-+ntVO; rjaC 1 fcir aIr rrT'nnr'Qtl ir lQ/v7in t i "T,.-
In the eradicative test, the fungicides which gave significantI
lower percentage of infection compared to the control were Orthc
side 75, Delsan A-D and Setrete. The best dose and length of dir
ping for each of these fungicides were Orthocide 75, 200 ppm fo
40 minutes; Delsan A-D, 200 ppm fof 30 minutes; Delsan A-D, 20
ppm for 30 minutes; and Setrete, 200 ppm for 20 minutes.
CELLULAR SLIME MOLDS FROM PHILIPPINE SOIL'
I. J. DOGMA, JR. and R. C. BLANCAVER2
Four species of cellular slime molds belonging to the genera Dic-
tyostelium and Polysphondylium were reported for the first time
from Philippine coils. Two described species, Dictyostelium muco-
roides Bref. and Polysphondylium violaceum Bref., showed variations
both in size ranges and morphological development. They were com-
monly isolated from forest soil and leaf mold samples only. Soil
samples from cultivated plots did not yield any representative of the
The Acrasiales are classified with uncertainty under the animal
or plant kingdom. These cellular slime molds show close affinity
with the protozoans by virtue of their amoeboid assimilative stage
(Bonner, 1959 and Alexopoulos, 1962). They are characterized b5
the coming together of amoeboid cells that give rise to elevated
fruiting bodies. In the process, however, the cells remain distinct
from each other and no protoplasmic fusions occur. Thus, these
organisms are excellent materials for investigating organization
and integration of separate intercellularly coordinated cells. Eco.
nomically, they play a vital role in the quantitative reduction of
the bacterial flora of soils for the myxamoebae normally depend
on bacteria for subsistence.
Members of the group have been reported from Poland in 1927
by Kremieniewski and Krzemienski (Harper, 1929), England (Singh
1947), India (Agnihothrula, 1956), Costa Rica (Huffman and Olive
1063) and from various parts of the United States (Raper, 1935
1941, 1956 and Raper and Quinlan, 1958). Raper (Singh, 1947'
isolated Dictyostelium spp. from soils obtained from Australia
Mexico, Cuba, Brazil, India and various stations throughout the
United States. They have been isolated from forest and cultivated
1 Part of this paper was read at the Second Annual Meeting of the Philippine
Phytopathological Society held at the U.P. College of Agriculture, April 10-11, 1965
2The authors are grateful to Mr. D. R. Reynolds, Department of Plant
Pathology, U.P. College of Agriculture, College, Laguna, for his encouragement
and advice in the course of the study; Mr. F. L. Nuque, Plant Protection Div-
ision, International Rice Research Institute, for supplying the soil samples from
Mindanao: and to Mr. R. Gonzales, Jr., Photographic Division, Forest Products
Research Institute, for the photomicrographs.
soils, compost, dungs of various animals, mushy hay, rotting woo(
and blades of grass floating in water. Usually, one can expect t
find these organisms in almost any place where vegetative matte
is undergoing aerobic decomposition (Raper, 1951). Even rhizo:
pheres of pigeon pea [Cajanus cajan (Linn.) Millsp.], peam
(Arachis hypogaea Linn.) (Agnihothrula, 1956) and Gomphrer
globosa Linn. (Rai and Tewari, 1961) were shown to harbor then
Hitherto, no account of these organisms has been made in tl
Philippines. This paper deals with the local isolation of four specie
belonging to the genera Dictyostelium and Polysphondylium, two (
which are described.
MATERIALS AND METHODS
Surface soil samples up to a depth of 1 inch were obtain
from cultivated plots around the College campus and at the Cei
tral Experiment Station, College, Laguna, Luzon. In a given plo
approximately 20 grams of soil samples were gathered at randon
Other cultivated soil samples from Davao and Bukidnon, Mind;
nao were also tested for the presence of these organisms. Fore!
soil samples were sporadically obtained near the gate of the U.
College of Forestry up to the peak of Mt. Maquiling, Laguna, L
zon. During a field trip to Taal volcano, situated in Taal Lak
Batangas. Luzon. leaf mold was likewise sporadically obtained froi
dense Ipil-ipil [Leucaena glauca (Linn.) Benth.] area in the crate
Approximately 10-gram leaf mold was collected per sample. A
collections were made from October to December, 1964. Sampl
were placed inside plastic bags.
Isolation procedure was carried out following the strea
method designed by Raper (1951). A ten gram sample was mixed
with 5 parts sterile water and ground in a mortar. The resultir
mixture was then streaked on diluted hay-infusion agar using
camel's-hair brush. Sub-cultures were obtained by transferrir
spores from well elevated mature sori to the intersection of cros
streaked colonies of Escherichia coli on the same medium. All ct
tures were kept under room temperature (28-290C) and renewed
every 3 weeks.
None of the cultivated soil samples from the College campu
Central Experiment Station or Mindanao yielded any member <
the group. Dictyostelium mucoroides Bref. was isolated from sai
p!es collected from Taal volcano and Mt. Maguiling. All the le;
mold samples from the former yielded D. mucoroides and Poi
v .r i- i i i
A white-spored isolate of Polysphondylium, possibly P. palli-
m Olive, was isolated from soil samples gathered from Bataan,
zon.3 The cultures, however, dried out and the organism could
longer be reisolated. Dictyostelium discoideum Raper was
o isolated from leaf mold samples obtained beyond the Mud
ring up to the peak of Mr. Maquiling on January 7, 1965. How-
'r. after 3 weeks in culture, it was lost due to rapid dessication
the medium on which it was grown with E. Coli.
Key to Two Genera and Four Species
sal disk present or absent; slug in stalked or stalkless migra-
tion; simple (if branched, branches never in whorls) .........
A. Dictyostelium Bref.
sal disk absent; slug in stalked migration; branches in whorls
of 2-4minute sorocarps; mature sorocarp resembles a minia-
ture pine tree ............ ...................................
B. Polysphondylium Bref.
A. DICTYOSTELIUM Bref.
sal disk present; slug in stalked migration; sorocarp erect, sim-
ple; sorus globose to apiculate; spores elliptical, hyaline,
6-9 x 2.5-3.5 u ...................... D. discoideum Raper.
sal disk absent; slug in stalked migration; sorocarp simple to
sparingly branched; sorus globose, milky white; spores ellip-
soid (a few spherical), pale, 6.3-11.4 x 3.9-7.4 u ...........
D. mucoroides Bref.
L1_____ L^ ______ ______
of its entire length and most frequently at the base. Pseudoplas-
modium variable in size and extent, often with numerous short
streams of myxamoebae (fig. 1). Stalked migration commences
Fig 1. Dictyostelium mucoroides Bref. Aggregation with less-defined outline
of streams. Nearby myxamoebae with conspicuous contractile vacuoles. 180 x.
CELLULAR SLIME MOLDS
even before all streaming myxamoebae have joined the cell mass
(soroger). In several cases, the large aggregating mass gives rise
to up to five sorocarps whos2 bases are joined with each other (fig.
2). Spores enmeshed in a slime material, oval to ellipsoid, some-
times nearly spherical, hyaline, thin-walled, 6.3 to 11.4 x 3.9 to 7.4
microns (fig. 3). Fully grown myxamoebae vary in size and shape
with very conspicuous contractile vacuoles (fig. 1). Microcysts are
abundant in old cultures, thin walled, 9.7 to 18.3u in diameter.
Polysphondylium violaceum Bref.
Polysphondylium violaceum is one of the largest members of
the Acrasiales. It is characterized by a long flexuous stalk with
a large terminal purple sorus and several side branches in whorls
bearing small purplish sori. Sorocarps solitary, up to 1 inch in
Fig. 2. Mature sorocarps (5) of D. mucoroides Bref. with basal portions closely
joined with each other. Note the solitary sorocarps and one-celled width of the
stalks. 90 x
'I*' -- ; 14'r)~''i'~~
Fig. 3. Spores of D. mucuroides Bref. Note the spherical spores (pointed by
arrows). Stained with rose bengal. 400 x.
length, tend to bend down due to the weight of the whorls from the
upper 3/4 of its entire length. Sorophores 1-celled (fig. 4), up to
35.8 microns in thickness at the middle; base bulbous, 4- to 6-celled,
up to 64.0 microns in width. Whorls consist of 2 to 4 branches,
each of which is a minute sorocarp, regularly spaced, up to 570.0
microns in length, bearing small purple sori, 79.6 to 238.3 microns
in diameter. Pseudoplasmodium variable in size and extent, with
long well-defined streams of myxamoebae (fig. 5). Stalked migra-
tion prolonged and resembles that of Dictyostelium mucoroides ex-
cept for the size of the cell mass (figs. 6 and 7). In the process of
migration, a portion of the rising cell mass is pinched off and left
behind the stalk to form the whorls (figs. 8 and 9). Spores are
embedded in a slime material, oval-shaped, slightly purplish, 6.8 to
12.9 x 3.0 to 7.8 microns (fig. 4). Myxamoebae vary in size and
shape. Microcysts are spherical, thin-walled and 10.9 to 21.0 microns
in diameter. Unbranched sorocarps are not uncommon, resembling
those of D. mucoroides except for the large purple sorus at the tip.
Sorocarps with irregularly arranged branches resemble those of the
aberrant strain described by Rai and Tewari (1963) from India.
SPolysphondylium pallidum resembles P. violaceum in forming
miniature "pine-tree" like sorocarps. It differs from the latter in
possessing white, globose sori, 50-80 microns in diameter (Raper,
CELLULAR SLIME MOLDS
1951). Both species can be encountered in forest soil and leaf mold
samples. Dictyostelium discoideum is characterized by a stalkless
migration stage and presence of a round basal disk supporting the
mature sorocarp. Except for these features, it closely resembles D.
Fig. 4. Spores and one-celled width of the sorophore of Polysphondylium vio-
laceum Brefela. Stained width rose bengal. 400 x.
Fig. 5. Pseudoplasmodium of P. violaceum Bref. with well-defined outline of
streams of myxamcebs. 90 x.
48 PHILIPPINE PHYTOPATHOLOGY
Fig, 6. Slug of P. violaceum Bref. in initial stalked migration showing the
streams of myxamcabe trailing the globose cell mass. 180 x.
Fig. 7. Prolonged stalked migration in P. violaceum with the sausage-like so-
rogen. Note the preformed stalk running along the entire length of the sorogen.
90 x. A i alLt.i tAali M-i III
Fig. 8. P. violaceum Bref. Culminating cell masses (shown by arrows) of the
whorl twisted around the main stalk.. Note the collapsed terminal sorus (upper
right hand corner) and unterminated aggregation of myxamoebae below the so-
rocarp. 90 x.
50 PHILIPPINE PHYTOPATHOLOGY
of myxamoebae below. 180 x.
S :-. .
ideum in stalkless migration would evolve, it would give rise to D.
The plots, from where the cultivated soil samples were ga-
thered, were constantly plowed over after each crop, and sprayed
with herbicides. These cultural operations could probably account
for the failure to isolate any representative of the group from cul-
tivated soil samples.
It is of interest to note that after a 1-month period of storage
of the soil samples and leaf molds in the lower-most chamber of
the refrigerator (20-220C), the organisms could no longer be iso-
lated. The microcysts and spores, which may have been present
in the samples, of D. mucoroides and P. violaceum, could have lost
their viability under low temperature. Studies have shown that
microcysts of cellular slime molds are covered with thin walls only
The tedious job of constantly renewing the cultures and the
apparent low percentage of reisolating the organism after 3 weeks
in culture are evidence of the need of a method to preserve them
over a period of time. Raper (1951) has been successful in pre-
serving spores of species of Dictyostelium and Polysphondylium
for almost 9 years by lyophilization. Agar slant cultures with E.
coli, with and without heavy mineral oil, had also been preserved
for 8 and 10 months, respectively.
The isolates described here showed great variability, both in
size ranges and morphological development. This variation was
not, however, surprising since most isolates of cellular slime molds
from the tropics commonly exhibit this phenomenon. Rai and Te-
wari (1961) had reported high variability among D. mucoroides
and P. violaceum in India. They noted that forms with short
stalks and with long trailing stalks of D. mucoroides resemble Dic-
tyostelium brevicaule Olive and D. giganteum Singh, respectively.
An aberrant strain of P. violaceum had also been reported (Rai
and Tewari, 1963). It was characterized by having stouter irregu-
larly branched sorocarps and larger pseudoplasmodia in stalked
migration. In Costa Rica, Huffman and Olive (1963) found a strain
of D. mucoroides that combined the characters of D. polycephalum
Raper and Polysphondylium. Morphological variations suggested
the necessity of revising the scheme of phylogeny for the Acrasiales
proposed earlier by Bonner (1959).
The sorocarp length of our isolate of P. violaceum was very
Ircrp rnmnnrpA rxi;tlh thn- +ro 1A l ----- *.A.....
(1963) gave the length range from 3.0 to 4.5 mm., about one-sixth
the length of our isolate (1 inch). With our isolate of D. muco-
roides, the appearance of large pseudoplasmodia that gave rise to
more than one sorocarp with basal portions closely joined with
each other was a developmental habit of D. polycephalum (Raper,
1956). This variation supported the view of Raper (1951) that D.
mucoroides can best be represented as a complex. Huffman and
Olive (1963) were of the opinion that D. mucoroides was the pi-
votal point in the phylogeny of the Acrasiales, possessing a genetic
pool that provided a considerable degree of plasticity for adapta-
tion to varying environments.
AGNIHOTHRULA, V. 1956. Occurrence of Dictyosteliaceae in the rhizophere of
plants in Southern India. Experientia 12: 149-150.
ALEXOPOULOS. C. J. Introductory mycology. 2nd ed. John Wiley & Sons, Inc.,
N. Y., USA.
BONNER, J. T. 1959. The cellular slime molds. Princeton Univ. Press, Princeton,
N. J., USA.
HARPER, R. A. 1929. Morphogenesis in Polysphondylium. Bull. Torrey Bot.
Club 56: 227-258.
HUFFMAN, D. N. and L. A. OLIVE. 1963. A significant morphogenetic variant of
Dictyostelium mucoroides. Mycologia 55: 337-341.
RAI, J. N. and J. P. TEWARI. 1961. Studies in cellular slime molds from In-
dian soils. I. On the occurrence of Dictyostelium mucoroides Bref. and
Polysphodylium violaceum Bref. Proc. Indian Acad, Sci. Sect. B. 53: 1-9.
.1963. Studies in cellular slime molds from Indian soils. II. On the
occurrence of an aberrant strain of Polysphodylium violaceum Bref., with
a discussion of the relevance of mode of branching of the sorocarp as a
criterion for classifying members of the Dictyosteliaceae. Proc. Indian Acad.
Sci. Sect. B. 58: 201-206.
RAPER, K. B. 1935. Dictyostelium discoideum, a new species of slime mold
from decaying forest leaves. Jour. Agric. Res. 50: 135-147.
1941. Dictyostelium minutum, a second new species of slime mold from
decaying forest leaves. Mycologia 33: 633-649.
.1951. Isolation, cultivation, and conservation of simple slime molds.
Quart. Rev. Biol. 26: 169-190.
1956. Dictyostelium polycephalum nsp.: a new slime mould with core-
miform fructifications. Jour. Gen. Microbiol. 14: 716-732.
and M. S, QUINIAN. 1958' Actyostelium leptosomum: A unique
cellular slime mold with an acellular stalk. Jour. Gen. Microbiol. 18: 16-32.
SINGH, B. N. 1947. Studies on soil Acrasieae. I. Distribution of species of
Dictyostelium in soils of Great Britain and the effect of bacteria on their
development. Jour. Gen. Microbiol. 1: 1121.
DR. GtORGE A. ZENTMYER, President-elect
American Phytopathological Society
President Castillo, officers and members of the Philippine
Phytopathological Society, guests and colleagues.
It is my great honor and pleasure to be invited to this most
significant 2nd annual meeting of the Philippine Phytopathological
Society. You made an admirable beginning in your inaugural ses-
sion last year, and the program for this year's meeting shows fine
progress. I certainly appreciate the invitation extended by Pres-
ident Castillo and other officers of the Society. and would like to
reiterate our appreciation for the wonderful hospitality extended
to my family and me.
As President-elect of the American Phytopathological Society,
I am very pleased to bring special greetings from nathologists in
the United States. President W. J. Zaumeyer has also sent a spe-
cial message to your Society.
The Philippine Phytopathological Society is one of the unique
organizations of the wolrd, as there are very few existing vhvto-
nathological societies, those in Japan, India, Mexico and the United
States. You have taken a wise step and have shown foresight, one
which will profoundly influence the development of plant path-
ology here in the Philippines.
I am happy to hear of the many new developments here in the
Philippines like the 5-year development program involving the mul-
timillion dollar expenditure for the expansion of the U. P. College
of Agriculture. and the new facilities for UPCA Plant Pathology
which will make the place an outstanding center for research and
I am also pleased to see your new official newsletter, The Syn-
drome which was first published in November. This is certainly
an original and informative approach to plant pathological news,
with contributions coming from the graduate and the undergrad-
uate students. The Philippine Agriculturist too has been a good
1 Delivered at the Philippine Phytonatholo-ical Society Banguet held at Lake
View Hotel, Los Bafios, Laguna, April 11, 1965.
agricultural publication for many years and I hope your new Phil-
ippine Phytopathology Journal would likewise be an exciting and
With the tremendous increase in population in recent years
and the even more sizeable increase that will soon be on us, Plant
Pathology will be of even more importance in the coming years.
There will be a vital need for abundant production of food, fiber
and other materials supplied by the plant kingdom. This will mean
an even more vital need for controlling devastating diseases that
cause tremendous losses in a wide variety of crops.
One of our noted American pathologists, Dr. E. C Stakman,
has antlv stated: "Man occupies this planet as a guest of the plant
kingdom." How true this is! Plants not onlh, rovide food for all
inhabitants of this world, but also shelter, clothing and other needs.
Ninety-five per cent of world's food supply comes from less
than a dozen crops wheat, rice, corn, beans, sugar cane. coconut,
cassava, potato, sweet potato, banana, and sorghum, and seventy-
five ner cent of the world's food production comes from the grass
There is no need for us to discuss how important plant dis-
eases are in the production of crops.
In these busy days, how often do we stop to realize that Plant
Pathology is really young as a science, it is only about 100 years
old. Of course, we are indebted to countless scientists and philo-
sophers for the background and steady development of science:
Greek philosophers Socrates, Plato, Aristotle, and Theophrastus;
microscope maker Antony von Leeuwenhoek; pathologist Benedict
Prevost; mycologist Anton de Bary; chemist and in'crobiologist
Louis Pasteur; and many others. Here in the Philippines, you have
your own Dr. Gerardo O. Ocfemia, Dear of Philippine Plant Path-
The emphasis in plant pathology is changing. I feel that the
most productive approach to any research, is succinctly stated by
Pavlov, "Do not become a mere recorder of facts, but seek to dis-
cover the mystery of their origin" and by King Solomon, "Under-
standing is the fountain of life." We now see increased emphasis
on basic research in studies of resistance to disease. rather than
being a static process is an active process, triggered by infection;
in remarkable advances in genetics of microorganism. transforma-
tion and transduction in bacteria, and elaboration of the basis for
variability in nlant nathoeenic fungi, resulting from mutation,
cytoplasmic inheritance, adaptation, heterokaryosis, sexual recom-
bination; exciting discoveries of virus structure and composition,
and in information gathered on the relation of ctr mrtroir tn +~r -
city and mechanism of action of fungicidal chemistry. These and
many other phases of research point toward the new science of
Our first obligation is to determine how best to control dis-
eases considering the conditions involved and the availability of
In case of rew problems, new areas (and there are still many
of these), we must come to know the problem, and to apply the
best possible control based on known measures than can be used
by the average farmer who may not have access to advanced equip-
ment. This means emphasis on prevention, resistance and cultural
methods. This is particularly true in countries with high percent-
ages of population involved in agricultural and huge land areas.
We must first provide the best possible control, only then can we
go into the science of plant pathology for more adequate under-
standing and ultimate better control.
Dr. Harrar has emphasized the need for international coope-
ration in plant pathology. This cannot be adequately emphasized
and I feel we are doing too little in this regard. We can do more
by working together to solve mutual or similar problems. Patho-
gens do not respect international boundaries, and are spreading
their horizons more rapidly and easily than ever before. Classical
examples of virulent disease introductions into the U. S. include:
Chestnut blight, Dutch elm disease, white pine blister rust, all
causing huge losses. We could cooperate more on epidemiological
studies, on joint studies of control of similar problems, on devel-
opment of disease-free stocks for international distribution, or
general dissemination of information useful in many similar areas,
and ultimately on basic studies of the pathogen, the disease, the
There are, of course, some efforts along these lines FAO,
some U. S. Aid programs, etc., but they are not enough. We need
more interchange between countries of students and investiga-
tors. In this aspect, we in U.S. have been pleased with visits by
a number of your country men and women like Drs. San Juan, del
Rosario and Mr. Martinez, one of our first M. S. students at River-
side. We need interchange too between Plant Pathology Societies
and I hope this will be forthcoming more in future years. Perhaps,
we need an International body of Plant Pathologists there is a
beginning in that regard in plans for an Internatonal Congress in
1968 in England. This is a fine opportunity too for cooperation
and international exchange in the Pacific Science Congresses.
Dr. Castillo asked if I could give some advice regarding your
new Phytopathological Society. From what I have seen at this
1Lfrr.L'JY2. rA Al IJrI vt Al ULUv.
meeting, I tnmil tme American mnytopatnological society coul
take some lessons from you. The spirit and enthusiasm of you
group is wonderful and these are vital factors in success!
The discussions papers are excellent. APS has become so larg
that unfortunately we are losing some of these features. We ofte
have 250 papers 2/2 days and spend 3 days for concurrent se!
sions. This is what you have to look forward to! The informs
aspect of the business meeting is also very refreshing, and you
financial situation appears to be true.
However, I can offer a few suggestions:
1. Initiate and maintain a first class publication, your journz
promises to be one. This will be a big drawing card fo
members and good advertising for your Society through
out the world.
2. Keep your committees active, to bring you fresh, new sue
gestions as to what your Society can and should do.
3. Maintain an active and continual drive for new members
4. Do as much as you can to promote International Coopera
5. Above all, maintain your enthusiasm and spirit.
May our cooperation, mutual understanding, exchanges of stu
dents, and staff, bear abundant, healthy fruit.
Again my deep appreciation for the invitation to join yot
in this fine meeting.