• TABLE OF CONTENTS
HIDE
 Front Cover
 Front Matter
 Front Matter
 Abstracts of Papers Accepted for...
 The pathological and mycological...
 Yellow dwarf of rice in the...
 Virus diseases of weeds in the...
 Fusarium head blight of wheat
 A comparative study of the alcohol...
 Pyhtopathological note
 Back Cover














Group Title: Journal of Tropical Plant Pathology
Title: Journal of tropical plant pathology
ALL VOLUMES CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00090520/00010
 Material Information
Title: Journal of tropical plant pathology
Series Title: Journal of tropical plant pathology.
Alternate Title: Journal of Philippine phytopathology
Philippine phytopathology
Physical Description: v. : ill. (some col.) ; 26 cm.
Language: English
Creator: Philippine Phytopathological Society
Publisher: Philippine Phytopathological Society
Place of Publication: Philippines
College Laguna
Publication Date: January-June 1967
Frequency: semiannual
regular
 Subjects
Subject: Plant diseases -- Periodicals -- Philippines   ( lcsh )
Plants, Protection of -- Periodicals -- Philippines   ( lcsh )
Genre: periodical   ( marcgt )
 Notes
Dates or Sequential Designation: v. 1, no. 1 (January 1965)-
General Note: Title from cover.
General Note: "Official publication of the Tropical Plant Pathology."
 Record Information
Bibliographic ID: UF00090520
Volume ID: VID00010
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 54382605
issn - 0115-0804

Table of Contents
    Front Cover
        Front Cover
    Front Matter
        Front Matter
    Front Matter
        Page i
        Page ii
    Abstracts of Papers Accepted for Presentation at the fourth annual meeting of the Philippine phytopathological society, Baguio City, June 9 and 10, 1967
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
    The pathological and mycological herbarium of the UPCA
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
    Yellow dwarf of rice in the Philippines
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
    Virus diseases of weeds in the Philippines II. Phaseolus lathyroides mosaic.
        Page 35
        Page 36
        Page 37
        Page 38
        Page 39
        Page 40
        Page 41
    Fusarium head blight of wheat
        Page 42
        Page 43
        Page 44
        Page 45
        Page 46
        Page 47
        Page 48
        Page 49
        Page 50
        Page 51
        Page 52
        Page 53
        Page 54
    A comparative study of the alcohol fermentation by three yeast isolates using molasses as the raw material
        Page 55
        Page 56
        Page 57
        Page 58
        Page 59
    Pyhtopathological note
        Page 60
        Page 61
        Page 62
        Page 63
        Page 64
    Back Cover
        Page 65
        Page 66
Full Text








Vol. 3 January and June, 1967 Nost



PHILIPPINE PHYTOPATHOLOGY


Official Organ of .


THE PHILIPPINE PHYTOPATHOLOGICAL SOCIETY


CONTENTS
*..1.

Abstracts of Papers Accepted for Presentation at the Fourth Annual
Meeting of the Philippine Phytopatbological Society, Baguio City,
June 9 and 10, 1967 .......................................... .

The Pathological and Mycological Herbarium of the UPCA
Tricita H. Quimio and A. H. Quimio ...... 22

Yellow Dwarf of Rice in the Philippines
M. K. Palomar and C T. Rivera ...... 27

Virus Diseases of Weeds in the Philippines II. Phaseolus lathyroides
Mosaic
Ma. Salome dfl Rosario, O. R. Paguio, and D. A. Benigno ...... 35

Fusarium Head Blight of Wheat
0. R. Exconde C. M. Napiere and F. D. Fuentes ...... 42

A Comparative Study of the Alcohol Fermentation by Three Yeast .
Isolates Using Molasses as the Raw Material
Lourdes C. Ignacio and R. V. Alicbusan ...... 55
*.4
PHYTOPATHOLOGICAL NOTE .
Chlorotic Ring Spot and Vein Ntcrosis of Rambutan ,?
A. N. Pordesimo ...... 60




o'|
I





















BIDRIN

SYSTEMIC
INSECTICIDE
PROTECTS YOUR
CROPS BETTER
IN 3 WAYS:
1. il inects on caract.
2. kils iecu tht suck the sp
of plats.
3. ls iuects thI ea leovesWi. Ai rs
and stem.
BDRIN is fuly absorbd by your plnh.
Thy thaftsel beow. paisonam to
ophid, bhed capdwpl s, grsa ppN
leanine., miss. i. slpca insect. ec.
BORmN is specdaly efldtive ag ric
Irfihopps d~ a immune to rwhr
nectiidd.
ecaue Of is stylic action. B.OR
ay be iprayp em during sm rail
eason. Four to ix wk after prca-
tin. crops mn be lrvestd without
fear ef poison.
Bidri poects a variety of crps much
as rice. mamgo% velebli. cius.
lOe nd pald m.


/1


Ihl c e














Founded on October 10, 1962 -

The P. P. S. Council 1967-1968
dent, MA. SALOME DEL ROSARIO, University of the Philippines, College,
Laguna
ing President, H. A. CUSTODIO, Bureau of Plant Industry, San Andres, Manila
President, ALFREDO V. PALO, B.P.I. Economic Garden, Los Bafios, Laguna
,tary, R. G. DAVIDE, University of the Philippines, College, Laguna
surer, IMELDA JOANO-QUINTANA, University of the Philippines, College,
Laguna
kr-in-Chief, A. N. PORDESIMO, University of the Philippines, College, Laguna

icilors:
F. C. QUEBRAL, University of the Philippines, College, Laguna (Luzon)
C. LUCERO, B.P.I. Regional Office, Cebu City (Visayas)
A. L. ELOJA, B.P.I., Davao City (Mindanao)

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


PHILIPPINE PHYTOPATHOLOGY
Official Organ of the Philippine Phytopathological Society

EDITORS
q. PORDESIMO, Editor-in-Chief, Department of Plant Pathology, University
of the Philippines, College, Laguna
'. GABRIEL, University of the Philippines, College, Laguna
E. LOPEZ, Philippine Sugar Institute, Quezon City
L. AQUILIZAN, Philippine Packing Corporation, Phillips, Bukidnon
L. CALICA, Bureau of Plant Industry, San Andres, Manila
iCILLA CHINTE-SANCHEZ, International Rice Research Institute, Los Bafios.
Laguna
BUSINESS MANAGEMENT
hess Manager, ROMULO F. P. QUEMADO, Union Carbide Phil., Inc. P.O. Box
Manila.
Subscriptions: Communications should be addressed to Mrs. Imelda Joano-Quin-
,College, Laguna. Subscription price: ?2.00 per copy for domestic and U.S.$1.00
'here. The Philippine Phytopathology is published semi-annually during the
;hs of January and June with its first issue in January, 1965. Deliveries over-
are not guaranteed; foreign mailings are made at the subscriber's risk. Mem-
ship in the Philippine Phytopathological Socie'y: Information concerning mem-
lip in the Philippine Phytopathological Society will be supplied by the Secretary
request. Advertisements: rates may be secured from the Business Manager.
endorsement of any statement of claims made in advertisements is assumed by
Journal or by the Philippine Phytopathological Society.


h














At least one auth r must be a member of The Philippine Phytopatho]
gical Society. A letter of transmittal from the responsible official with
his institution should preferably accompany any manuscript.
Manuscript: Two copies should be submitted, type on 8 1/2 x 11 in
paper double space throughout, including tables, legends, and citations. Ami
margins should be left on each side and bottom. Author's position, acknov
edgments, acceptance date, etc., should follow author's name, and will n
appear as footnote. Papers other than Notes may be organized convenient
under: Abstract, Review of Literature (if needed), Materials and Methoc
Results, Discussion, and Literature Cited sections. Further subdivisions
the Results section may be desirable. Avoid footnotes. The page numb
and author's name should appear in the upper right-hand corner of ea
manuscript page. The author's institutional address should appear benea
his name.
Tables should be numbered consecutively, and each type on a separs
page. Tables must have descriptive headings and should be understandal
without reference to the text. Lower case superscript letters are to be us
for footnotes to tables. Pages containing tables should follow Literatu
Cited, and should be numbered accordingly.
Figures (graphs, line drawings, and photographs) should add clearly
an understanding of the paper. The size and arrangement of figures shou
correspond to Journal page. Combine illustrations in composite cuts wh
possible, and number each unit to correspond with the text figure referen,
using consecutive Arabic numerals. Label each illustration in pencil on t
reverse side with the figure number and author's name. Legends for figure
should be typed together on a separate numbered page following the table
For style details follow: Conference of Biological Editors, Committee
Form and Style. 1964. Style Manual for Biological Journals (Second E,
tion). Amer. Inst. Biol. Sci. Washington, D.C. 117 p. Authors are urged
have one or more colleagues read a manuscript critically before submitti
it for publication. Manuscripts and editorial correspondence should be se
to the editor-in-chief. Submission implies nonsubmission elsewhere and
accepted) no publication elsewhere in the same form without consent..

ERRATA (Vol. 2, Nos. 1 and 2)

Page 4- 2nd paragraph: last sentence should read "Determination of mite spec
associated with zonate chlorosis is being pursued at the Lipa Experimf
Station."
Page 14 2nd paragraph: 1st line should read "A virus associate,' with vein yelk
ing and apparent stunting of sweet potato." 2nd lirip" mit "of sweet pota
after apparent.
Page 56 & 57: Captions were interchanged: Fig. 2 should be Fig. 3 and vice vern

ii


ATION YF













ABSTRACTS OF PAPERS ACCEPTED FOR PRESENTATION
AT THE FOURTH ANNUAL MEETING OF THE PHILIPPINE
PHYTOPATHOLOGICAL SOCIETY, BAGUIO CITY
JUNE 9, 10, 1967

(Arranged alphabetically according to first author's surname)

A survey of the Order Mucorales in the UPCA Campus. B. A.
dvincula. A preliminary survey of the Order Mucorales in the soil
id in the atmosphere of the UPCA Campus was conducted. Isolation
this particular group of fungi was done by exposing plated potato-
xtrose-agar medium in the atmosphere and by the soil-plating method.
ie to the inadequacy of available literature, the species identification
some isolated fungi was not yet ascertained. About 35 isolates ob-
ined belong to 6 genera in 3 families.
Reaction of new soybean strains and standard varieties to rust. -
B. Ballon and A. V. Hernaez, Jr.- Differential reaction of newly
veloped strains and standard varieties of soybean to rust caused by
e fungus Uromyces sojae was studied. Statistical analysis of the data
i spot count per leaflet showed highly significant differences among
tries.
Differences in yield due to the disease was highly significant among
me of the new strains and standard varieties. A study on the relation-
ip between yield and degree of infection indicated that varieties or
rains with low spot count tend to give higher yield than those with
gh spot count. This was clearly shown by the highly-resistant standard
.riety Sankuro and a strain developed from the cross EG, x Sk.
Further tests ,of fungicides for the control of soybean rust. C. R.
itoon and Luz G. Rubia.- A further test of fungicides to control
ybean rust caused by Uromyces sojae was done. Shell Copper fungi-
le, Copper Lonacol and Antracol, were sprayed at intervals of 7 and
days and at the rates of 0.0, 1.5 and 3.0 g per gal of water. Statis-
:al analysis of the yield data showed that there were no significant
fferences among fungicides and among any of the spraying intervals.
awever, highly significant differences were obtained among rates of
iplication. The yield of plots sprayed with either 1.5 or 3.0 g per gal

1













actions among fungicides and rates of application, spraying intervals
rates of application were highly significant.
Some physiological responses and characteristics of Auricularia p
tricha in laboratory culture. Jane D. Borromeo. Auricularia p
tricha (Mont.) Sacc. grew well on malt agar, potato dextrose agar
rice bran decoction agar, at a pH ranging from 6.5 to 7.5, and a
temperature of 28 C. Light induced the production of brown gelatir
matrix similar to that produced in fruit body formation. Cultures
malt agar medium at room (25-30 C) and refrigeration (15-20 C) t
peratures were viable up to 6 months. Rice bran is the best nati
substrate for spawn preparation and production as it supported the th
est and most compact growth. The cultural characteristics of A. p
tricha were studied and described. Recommendations and certain 1
editions to be met in the artificial cultivation of A polytricha are i
gested.
Chemical control of potato late blight. Ruth P. Calo and Cefel
A. Baniqued. Six fungicides were tested against Phytophthora in
tans (Mont.) de Bary. These were Dithane M-45, Dithane M-22, Ma:
Flit 406, Copper Curit, and Cuproxol, each applied at the rate of 1
per gal of water. The experiment consisted of 7 treatments incluu
the control, replicated 3 times. The first spray was applied when I
were completely emerged and subsequent sprays were applied at wel
intervals for 12 weeks. Insecticide was incorporated in each spra
control pests feeding on the crop. The control plots and border pl;
between treatments were also sprayed with insecticide. Evaluatior
the efficacy of the fungicides was made 2 weeks before harvest
immediately after harvest, using late blight incidence and weight
marketable tubers as criteria.
All test fungicides protected the potato leaves from blight. H
ever, the first 5 fungicides had better control than those of copper b
On the general stand of the experimental plants, those treated 1
Dithane M-45, Flit 406, and Dithane M-22 had darker green leaves
were more vigorous than those treated with Copper Curit, Maneb,
Cuproxol. This may account for the higher yield of marketable tub
Some species of Phyllachora found in Los Bafios and other area
the Philippines.- S. C. Dalmacio. The genus Phyllachora belong!
the family Phyllachoraceae of the Order Sphaeriales, Class AscomycE













.scus contain 8 spores which are hyaline and one-celled.
In the present study, 28 specimens, most of which were collected in
,os Bafios were examined. All microscopic details have been studied
inder the high power objective. Plain lactophenol mixed with phloxine
proved satisfactory in studying the asci and ascospores.
Out of the 28 specimens examined only 13 were identified to species.
These were Phyllachora cynodontis (Sacc.) Niessl., P. dalbergiicola P.
lenn., var. philippinensis (Theiss. & Sydow) Petr., P. elmeri Sydow, P.
:aernbachii P. Henn., P. orbicula Rehm, P. imperata Sydow, P. sacchari-
pontanei Sydow, P. graminis (Pers.) Fuckel f. panici (Schw.) Shear.,
>. pterocarpi Sydow, P. phaeolina Sydow, P. stenospora (Berk. & Br.)
iacc., P. minutissima (Welm. & Curr.) A. L. Smith and P. sorghi v.
Ioehnel.
Some of the identified species slightly differ in size or shape from
he type species described by previous workers. Phyllachora elmeri
vhich was described by Sydow seemed to be the same as P. kaernbachii
vhich was described by Hennings. Asci and ascospores of both species
vere indistinguishable. Another two species resembling each other were
'. sorghi v. Hoehnel and P. coicis P. Henn. Asci and ascospores of P.
*orghi measured from 90-130 x 13-20 u and 18-24 x 12 u, respectively;
hose of P. coicis measured from 90-110 x 18-20 u and 20-24 x 11-13.5 u,
respectively. Both species were reported to occur on different host
plants but considering the size and shape of the asci and ascospores,
hey were indistinguishable. From these observations and descriptions
riven in the literature, it is probable that P. sorghi and P. coicis are but
nly one species and the same might hold true to P. elmeri and P.
-aernbachii.
Development of Meloidogyne incognita on susceptible hosts under
fieldd conditions. R. G. Davide. Susceptible host (tomato var. Mar-
flobe, Ampalaya native var. and cabbage var. Early Glory were grown
n 6-inch clay pots. Each plant in a pot was inoculated with approxi-
nately 100-200 second-stage larvae of Meloidogyne incognita Chitwood.
Twenty-five plants were inoculated in every experiment. Twenty-four
lours after inoculation, the pots were wrapped with plastic bags (to
Lvoid nematode contamination in the field) and buried 6-inch deep be-
ow the soil surface in the experimental field. Since soil temperature
vas regarded an important factor in the development of the nematode,
-ecords were taken 3 times a day, i.e., between 7 and 8:00 a.m., 1 and










'PTNE PHVTC


2:00 p.m., and 5 and 6:00 p.m. at one-day interval throughout the dur
tion of the experiment. The rate of development of the nematodes w.
determined by examining 2 or 3 plants at 7, 10, 13, 16, and 19 da:
after inoculation. Five trials were conducted throughout the rainy ar
dry seasons.
The results indicated that under tropical conditions of the Phili]
pines, Meloidogyne incognita develop much faster than under tempera
conditions. There is evidence that suggests the influence of soil ter
perature on the development of the nematodes. For instance, the nem,
todes developed at faster rate on tomato and ampalaya (bitter gourd
where the soil temperature ranged from 25-29 C or an average of 27.
C in September and November part of the rainy season. At 10 da
after inoculation some of the larvae already reached the adult stage ar
within 16 to 19 days majority of them were already producing egi
and egg masses. On the other hand, the rate of development of tl
nematodes was somewhat delayed on cabbage when the soil temperatui
in December ranged from 25-28 C or an average of 26.7 C. Under th
condition the nematodes were still in the larval stages of developers
10 days after inoculation. In 19 days majority of the nematodes has
not started laying eggs. A somewhat similar trend of results were ol
trained on tomato experiment in summer time (April) where the so
temperature ranged from 26 to 35 C or an average of 29.6 C durir
the day. It seems, however, that the wider range of soil temperatui
also affected the rate of development of the nematodes. Under summ(
conditions the soil temperature usually is warmer during the day ar
cooler during the night. The results evidently showed that under th:
condition, none of the nematodes reached the adult stage in 10 days bi
they did in 13 days. In 19 days majority of the nematodes reached tl
adult stage but few have started producing eggs and egg masses. I
all experiments, males were rarely observed, thus suggesting that tl
females must have reproduced by parthenogenesis.
Reactions of various breeding lines of tomato and ampalaya i
Meloidogyne incognita. R. G. Davide and J. R. Deanon, Jr. Sever;
lines of tomato and ampalaya (bitter gourd) were tested for resistan(
against the most common species of the root-knot nematode, Meloidogyr
incognita Chitwood. The plants were grown in autoclaved soil contain
in 6-inch clay pots (with 2-3 plants per pot). Three to 4 weeks after
planting the plants ere inoculated with approximately 2,000 larvae c
M. incognita per pot. Two months after inoculation the root system c
each plant was examined for gall development. The degree of galling ws













ed as follows: 1 for no galling, 2 for trace, 3 for slight, 4 for moder-
,and 5 for severe.
The results revealed that none of the 14 lines of ampalaya tested
>wed resistance to the nematode. On the other hand, 8 of the 13 lines
tomato showed high degree of resistance to the nematode. Examina-
n of the root systems of these resistant lines indicated that few larvae
re penetrated the roots and failed to develop beyond the second stage.
e development of root necrosis, a typical resistant reaction to the ne-
tode, was observed on these resistant lines of tomatoes.
Philippine Saprolegniaceae: Achlya and Aphanomyces. Irineo J.
gma, Jr.-Five hundred and thirty-eight water- and 371 soil-samples
;ained from the vegetable and rice areas of Luzon yielded 293 water-
Id isolates. In the genera Achlya and Aphanomyces, Achlya klebsiana
Waters, A. proliferoides Cocker, A. flagellata Coker, A. bisexualis Coker
I A. ambisexualis J. R. Raper and Aphanomyces laevis de Bary were
notified.
A comparison with the morphologic and taxonomic diagnosis of
al species with their temperate counterparts shows that local species
riate in having smaller oogonia and oospores and lesser number of
spores in the oogonial cavity. Furthermore, the Philippine materials
tinctively produce non-ornamented oogonia that invariably show the
:uliar flaring up of the oogonial stalk apex into the oogonial cavity.
Comparative study of alcohol fermentation by three yeast isolates
ing molasses as raw material. Lourdes C. Ignacio and R. V. Alic-
san. Comparative studies were made on 3 different yeast strains
an attempt to find a good distillery yeast. The yeast strains studied
re Champagne, Tuba, and Magne. The highest percentage of molasses
ed was 30%o. The percentage of alcohol based on total fermentable
Tars for Magne, Tuba, and Champagne were 49.50, 46.30 and 43.77%,
;pectively. Magne yeast gave the fastest rate of fermentation, fol-
ved by Tuba, and lastly by Champagne.
Acetaldehyde, another metabolic product of fermentation was also
alyzed. Magne, Tuba, and Champagne produced 9.65, 21.71 and 8.50
r acetaldehyde per 100 ml distillate, respectively.
Magne yeast was found to be the best distillery yeast among the
strains based on the following criteria: (a) ability to yield high per-
itage of alcohol, (b) efficiency in the conversion of carbohydrates to
.-1, -1 n- 4 /-\ _l m-1.4- 4- .+--- .- -; + .n .pnn~r n...













Breeding for efficient transmitting colony of Nilaparvata lugens,
vector of rice grassy stunt virus.--K. C. Ling and V. M. Aguiero.-
The incidence of grassy stunt virus disease, transmitted by Nilaparvata
lugens, recently increased in the paddy field particularly in certain sea-
sons. Field observations on about 5,000 rice varieties under natural in-
fection showed that some varieties had a low percentage of infected
hills. A method for testing varietal resistance became necessary, how-
ever, only 30% of an insect population collected from the field are active
transmitters. Breeding an active colony for artificial inoculation became
imperative.
Second to 4th instar nymphs that previously fed on diseased plants
for about 10 days were tested individually for transmission using Tai-
chung Native 1 as test plants. The insects were then transferred indi-
vidually to marked test tubes. After 2-4 days, the adults were paired
and mated in test tubes where the females were allowed to oviposit.
The nymphs hatching from each pair were kept on diseased plants and
subsequently tested. This procedure was carried on for several genera-
tions until a fairly stable active colony was obtained.
Preliminary results indicate that about 31% of the individuals in
the F, and 54% in the F2 progenies transmit the virus.
Preliminary studies on the feeding habits of Nephotettix impicticeps.
- K. C. Ling and M. K. Palomar. Attempts were made to understand
the feeding habits of Nephotettix impicticeps Ishihara, vector of rice
tungro virus, in order to explain the mechanism of resistance of Pank-
hari 203 to the disease. Experimental results revealed a significant re-
duction in the life span of insects that fed on seedlings of Pankhari
203, a tungro-resistant variety, as compared to Taichung Native 1, a
highly susceptible variety. No difference in life span, however, was
found among leafhoppers that fed on detached leaves of these two rice
varieties.

Feeding punctures of 13.3 x 6.1 and 13.9 x 5.5 u were observed
on leaf blades of Pankhari 203 and Taichung Native 1, respectively,
using an erythrosin stain. Examinations of safranin-stained salivary
tracts in cross-sections of the leaf blade in both varieties showed no
difference in the termination of stylet penetration. The stylet usually
reached the phloem cells rarely xylem and parenchyma cells.
It seems that N. impicticeps is primarily a phloem feeder and that













Inability of the stylet of insects to penetrate its leaves.
Soil fumigation for the control of plant parasitic nematodes infest-
g Sumatra tobacco seedbeds.- C. P. Madamba, C. G. Goseco, P. D.
agoyo and A. P. Navarro. Four commercially available soil fumi-
ints, viz., Agrene, D-D, Dowfume MC-2 and Edabrom were evaluated
r the control of plant parasitic nematodes infesting Sumatra tobacco
edbeds at Tubao, La Union and Ilagan, Isabela. Dowfume MC-2, D-D,
Ld Edabrom gave excellent control of root-knot (Meloidogyne incognita)
id spiral nematodes in both sites. Root-knot infection in the treated
ds ranged from 0.05 to 7% while in the control, infection ranged
om 90 to 100%. Root-knot control was better in the sandy loam soil
Tubao than in the clay loam soil of Ilagan. These treatments also
ve good control of weeds for 25 days after application but Dowfume
C-2 proved to be the most efficient nematocidal-herbicidal treatment.
edlings in the treated plots were more vigorous and healthy than
ose in the untreated plots.
Effect of soil fumigation on nematode population and plant growth
Sumatra wrapper tobacco. C. P. Madamba, C. G. Goseco and R. K.
ilis. D-D, Dowfume W-85, Edabrom 500, Edabrom 750, and Telone
3C, showed excellent control of plant parasitic nematodes infesting
Imatra wrapper tobacco field in Tubao, La Union. Nematode popula-
uns especially spiral and root-knot nematodes were significantly re-
ced. Gall index ratings were "none" to "light" in the fumigated field
compared to "moderate" to "heavy" in untreated areas.
There was a significant increase of 10 to 16 cm in the height of
sated plants over those in the control. An increase in the number and
eight of marketable leaves was also evident from plants grown in fields
sated with D-D, Dowfume W-85, and Edabrom 500. Lesser incidence
wilts was likewise observed in fumigated fields.

Reactions of tristeza-tolerant budlings of different scion-rootstock
nbinations to citrus leaf-mottle-yellows virus.--A. L. Martinez.--
!althy tristeza-tolerant budlings of different scion-rootstock combina-
ns, which were established through seedlings grown from seeds in
3 greenhouse, were tissue-graft inoculated from small trees of Szinkom
Calamandarin rootstock infected with leaf-mottle-yellows virus of
rus. The leaf-mottle-yellows virus was obtained by means of Diapho-
ta citri Kuway from selected orchard trees displaying different stages












5 t'HILIPPINE rHYTOPATHOLOGY

Madam Vinous sweet oranges and Ponkam and Szinkom mandarins or
various rootstock varieties viz., Calamandarin, Cleopatra mandarin, Car
rizo, Florida rough lemon, Madam Vinous sweet orange, Rangpur lime
Sunki, trifoliate orange and Troyer citrange. Some healthy budlings oj
each combination were uninoculated to serve as checks. All the inocu
1 .1 snnA nn-4-fn4n l c nnt r nhciTna ... 4-a lhlfl?;f-rl-














Vinous), trifoliate orange and Troyer citrange were tissue-graft inocu-
lated from selected field trees which were previously demonstrated to
carry only a mixture of tristeza and psorosis viruses. Except Calaman-
darin, Ladu, Szinkom, trifoliate orange and Troyer citrange, all the other
inoculated seedlings displayed symptoms of vein clearing and stem pit-
ting such as had been originally described and established on tristeza-
susceptible varieties. Of the varieties that did not show any tristeza
symptoms, only trifoliate orange was found free from tristeza through
continuous indexing tests to lime for a period of 3 years. Psorosis symp-
toms which consisted of vein flecking, leaf distortion, and shock reaction
with leaf and bud defoliation and necrosis of young tissues were ob-
tained on Calamandarin, grapefruit, Key lime, Ladu, Szinkom and sweet
orange. Although no symptoms were observed on the other varieties,
psorosis virus was obtained in these varieties through indexing to seed-
lings of sweet orange.
These results show that psorosis virus can infect all the varieties
tested. In addition to the various varieties which are considered to be
ideal indicators for psorosis virus in other countries, Calamandarin,
Ladu and Szinkom mandarin are good indicators for this virus. Tristeza
virus was not recovered from the inoculated trifoliate seedlings; this
corroborates previous results and the findings of some workers elsewhere
that the tristeza virus does not probably multiply or maintain itself in
the tissues of trifoliate orange.
Additional experimental evidence of relationship between viruses
causing citrus seedling yellows and tristeza. A. L. Martinez and D. M.
Nora. Studies were conducted to obtain further information regard-
ing the relationship between citrus seedling yellows (SY) and tristeza
(T) viruses. Isolates of SY and T viruses were established on Key lime
seedlings by aphid transmission from naturally-infected seedling trees
of calamondin (calamansi). All SY and T isolates induced symptoms
of vein clearing and stem pitting on lime seedlings (lime reaction). Also,
the SY isolates induced yellows symptoms on seedlings of Eureka lemon.
The T isolates did not induce such symptoms on lemon. Although vary-
ing in severity of symptoms and incubation period, the SY and T isolates
induced characteristic tristeza reaction on small trees of Szinkom and
Ladu mandarin and Valencia orange on Eureka lemon and sour orange
~nnfA^n-a A _nn +n;i^l rvaino+ Pihallynoinor innnilnstions with SY iso-










PHILIPPINE PHYTOPATHOL


lates. All the SY and T isolates were not recovered from previously
graft-inoculated seedlings of trifoliate orange suggesting that SY or T
virus cannot establish itself in the tissues of trifoliate orange. Both SY
and T viruses were transmitted by tissue graft and by the aphid Toxop.
tera citricidus. Attempts to mechanically transmit SY and T to some
citrus varieties and non-citrus species yielded negative results. The re-
sults presented show additional evidence that seedling yellows virus is
related to the tristeza virus. Also, it can be concluded that seedling
yellows is caused by a severe strain of tristeza virus.
Physiologic races of Piricularia oryzae from single blast lesion. -
S. H. Ou and M. R. Ayad.- Monosporial cultures of Piricularia oryzae
Cav. were obtained from single lesions. Stock cultures in PDA were
kept in cool (4 C) room.
These single spore cultures were artificially inoculated on the Inter-
national and Philippine differentials composed of 18 varieties. Reaction
of these differentials was taken 7 days after inoculation. Among the 56
single spore isolates obtained from the first lesion, 14 Philippine races
(P16, P26, P38, P30, P52, P54, P55, P56, P57, P58, P59, P69, P70 and
P73) were identified. Based on the International differentials, 9 races
(IA-1, IA-2, IA-3, IA-5, IA-6, IA-13, IA-14, IC-5 and ID-5) were dis-
tinguished.
Among the 44 single spore isolates from the second lesion, 8 Phil-
ippine pathogenic races (P, P8, P12, P36, P62, P63, P64 and P71) were
determined. Using the International set of differentials, 8 races (IA-1,
IA-2, IA-3, IA-11, IA-17, IA-18, IB-6, and ID-2) were found.

The results indicate that the fungus readily undergoes changes and
produces variants differing from the parental type in the degree of
pathogenicity.
Resistance of IRRI world collection and Philippine seedboard rice
varieties to bacterial leaf blight. S. H. Ou, F. L. Nuque and J. P. Silva.
- In 1965, 3275 varieties were tested for resistance to isolate B72 of
Xanthomonas oryzae (Uyeda et Ishiyama) Dowson. In 1966, another
3676 varieties were preliminary screened at flowering stage for re-
sistance to isolate B15 in the field. Varietal reactions based on 10 disease
scales were taken 20 days after inoculation. Two hundred sixty-three
varieties have shown resistant reaction (disease scale 0-3), 1173, inter-
mediate (disease scale 4-6) and 2240, susceptible (disease scale 7-9).
The resistant varieties were reinoculated with isolate B6, B15 and B2










ABSTRACTS


at seecanng stage and with isolates B72 and B15 at flowering. The fol-
lowing varieties were found highly resistant at both stages: Wase Aikoku
3, Baifufugoya, Early Prolific sel. 1028P, Lacrose x Zenith, Semora
Mangga, Lacrose x Zenith-Nira, Norin 25, PI 209938, Giza 38, Zenith,
Nagkayat and Malagkit Sungsong.
The Philippine Seedboard Varieties were likewise inoculated with
isolates B6 and B15 at seedling stage. The result showed that all the
seedboard varieties are susceptible to these two virulent strains.
Further studies on physiologic races 'of Piricularia oryzae in the
Philippines. S. H. Ou, F. L. Nuque, T. T. Ebron, Jr. and C. Von Chong.
- In addition to the 100 isolates earlier reported by Bandong and Ou
in 1966, 148 single-spore isolates were inoculated on 8 International and
12 Philippine differential varieties. Based on the Philippine differentials
21 more races were identified. Using the suggested International dif-
ferential varieties, these races were classified into 28 international race
groups.
Majority of the isolates so far tested belong to races P9, P25 and
P11, each with 28, 24 and 19 isolates, respectively; P21, P23, P32, P8
and P20, each with 16, 16, 13, 13, and 10 isolates, respectively. These
results indicate the prevailing races in the Philippines.
In so far as regional distribution of races is concerned, P9 and P25
are prevalent in Northern Luzon and Central Luzon, respectively. The
prevailing races in Southern Luzon are P11 and P21. Bicol Region and
Western Visayas have 2 prevailing races each: P23 and P21 in the for-
mer and P23 and P11 in the latter. In Eastern Visayas, the most com-
mon race is P8, whereas race P25 and P8 are common in Mindanao.
Effect of nitrogen and temperatures on the development of bacterial
blight lesions in rice. S. H. Ou, F. L. Nuque, J. P. Silva and S. T. Hsu.
- The effect of low (no nitrogen added) and high nitrogen level [60 g
(NH,) 2S04/10 k soil] on lesion expansion by Xanthomonas oryzae in 2
resistant, 2 intermediate and 2 susceptible rice varieties was studied. The
treatments were replicated 3 times. The plants were inoculated at flower-
ing stage with isolate B72 and measurement of lesion was taken 30 days
after inoculation. Statistical analysis of the data show no significant
differences between the two treatments and among replications but high-
ly significant among varieties.
In another experiment, seedlings of Malo-mone (susceptible) and
Mayang Sagumpal (resistant) grown in culture solutions of 5, 10, 20,










PHILIPPINE PHYTOPATHOL


40, 80, 120 and 160 ppm of N were inoculated at 5-leaf stage. The lesior
were measured 14 days after inoculation. The expansion of lesions o
Mayang Sagumpal and early development of leaf lesions on Malo-mor
were slightly influenced by N concentrations. On Malo-mone, "kresek
symptoms were observed at 20 ppm of N or higher but not at 5 and 1


on Mayang aagi
The effect c
ties (3 resistant,
grown in plastic
and then placed
(28 2 C) tel
oculated with is
14 and 20 days
lesion progress
symptoms devel
after inoculatior
temperature dur
Pathogenicit
Ou, F. L. Nuque
of Xanthomonas
tain information
spectrum for res
ties with resist.
stare. The result


ter inoculation. No "kresek" symptoms were develop.
impal at any concentration.

f temperature was studied using another set of 8 varied
2 intermediate and 3 susceptible). These varieties wer
seedling cases under greenhouse conditions for 25 day
in 2 Percival chambers with low (21 2 C) and hig
aperatures 3 days before inoculation. Plants were in
plates B6 and B15 at 4-leaf stage and readings take
after inoculation. The results show that in all varieties
I much more rapidly at high temperature. "Kresek
)ped on intermediate and susceptible varieties 20 day
. However, no "kresek" symptoms were noted at lo)
ing the same period.
y patterns of strains of Xanthomonas oryzae. S. 1
and J. P. Silva. Pathogenicity patterns of 50 strain
oryzae (Uyeda et Ishiyama) Dowson were studied to olt
on varietal resistance and to select varieties with broa
instance. These isolates were inoculated to 24 rice varic
Int, intermediate and susceptible reactions at seedlin


are tne most virulent strams.
Four general patterns of pathogenicity were noted in the 50 strain
studied. Pattern 1 as exhibited by B6 corresponds to extreme virulence
It caused moderate, susceptible and highly susceptible reactions on know
resistant, moderately resistant and susceptible varieties, respectively
Pattern 2 represented by B23 corresponds to least virulence among the
strains used. It induced immune reaction on resistant varieties, resistan
reaction on intermediate groups and intermediate reactions on suscepti
ble varieties. Pattern 3 as exemplified by B72 corresponds to slightly!
lesser virulence than Pattern 1 but appreciable differences in reaction
were noted between resistant and susceptible varieties. Pattern 4 typi
fied by B59 showed much less differences in reactions in both resistan
and susceptible varieties. Reactions exhibited on these varieties were
more or less intermediate. Other patterns may also be recognized. Some













strains caused more or less moderate reactions on both resistant and
intermediate varieties but severe symptoms on susceptible ones, others
caused resistant reaction in resistant varieties but susceptible reaction
.n both intermediate and susceptible varieties.

Variation in pathogenicity of Piricularia oryzae in pure culture. -
3. H. Ou and Priscilla C. Sanchez. The blast fungus Piricularia oryzae
Cav. is known to have many physiologic races that occur in nature. Ex-
3eriments were conducted to find the variability of this fungus in culture
with respect to pathogenicity.

Fifty monospore cultures from each of the pure culture of isolate
[-42 (race P-2), 1-120 (race P-l), 1-129 (race P-12) and 1-143 (race
P-3) were grown on coconut milk agar medium. They were tested sepa-
rately on the 12 Philippine differential varieties.

Pathogenicity tests indicate extreme variability of the fungus. In
[-42, 12 races were differentiated; in 1-120, 9 races; in 1-129, 10 races
and in 1-143, 7 other races. Many of them do not conform with any
of the known races in the Philippines.

Preliminary study on the effect of toxins produced by Piricularia
"Dt Q TTn- r -A o 1 PQ-i-, f a,,r,^r,- __ 7 -.- ---













1 i re:wa utrj riauucrvny uayar anra otabm nurogen ratio to rice otas
-- S. H. Ou, Priscilla C. Sanchez and H. T. Hsu.-Two hundred an
forty-two isolates of Piricularia oryzae Cav. were inoculated to 15 ric
varieties. Analysis of the 15 varieties for their nitrogen and sugar coi
tents showed high correlation (r = + 0.8) between the ratio of reducing
sugar and total nitrogen (RS/N) and number of isolates which can ii
fect the varieties. Varieties with low RS/N ratio are infected by a hig
percentage of isolates while those with high ratio are resistant to a gres
majority of isolates.
The study further revealed that both resistant and susceptible vw
rieties have similar kinds of sugars, amino acids and other nitrogenot
compounds. Quantitatively, susceptible varieties have relatively hig
soluble nitrogen content but at higher level of soil nitrogen, the solub
nitrogen also increases in the resistant varieties. The higher nitrogen
content may not account for susceptibility of rice varieties to the path
gen.
Brown tip of ramie. A. V. Palo and A. Aragones. Examinatior
of brown tips of ramie at the laboratory of KENRAM (PHILIPPINES
INC. in Isulan, Cotabato showed the presence of Aphelenchoides sp.
Further examinations of samples at the BPI Economic Garden co
elected from ramie plantation at KENRAM in March, 1967 was unde:
taken. The tips were classified according to the stage of developers
of the disease as follows: early, medium and advanced. The present(
ef nematodes was determined from individual tips. The result of tt
study showed that all the tips at the early, medium and advanced stag(
of disease development contained Aphelenchoides sp. at different stag(
of development. The population counts for tips at the early, medium an
advanced stages varied from 4-118, 11-260 and 2-186, respectively.
Examinations of flowers and leaves also revealed the presence (
Aphelenchoides sp. Five 4.5-g leaf samples taken after chopping an
thoroughly mixing the leaves from the 53 tops, gave the following popi
lation counts: 9, 11, 11, 16 and 6. Results of pathogenicity tests ind
cated that the nematodes did cause the brown tip disease.
Plant parasitic nematodes extracted from the soil and dormant buc
of ramie rhizomes. A. V. Palo and A. Aragones. Extraction of nem;
todes by the sieve method from soil samples collected March, 1967 i
4-1,- U--,- _1,-^4- ,-C TO TD A li /TITTTT TT kTT 'VaC\ TWTfC -t4 T-.l,













rus and Criconemoides. Population counts of Xiphinema was quite
h but Meloidogyne was much higher, most common and root galling
s very severe.

The rhizomes were not attacked by the nematodes but dormant buds
re. Examinations of the nematodes under a compound microscope in-
ated that they were plant parasitic. Some buds were infected with
vae and adult males and females of Meloidogyne, some with larvae of
helenchoides and others either with a combination of Meloidogyne and
ratylenchus or Meloidogyne and Aphelenchoides or a combination of
three. Nematode counts were done to determine the number of a par-
Ilar species infecting dormant buds.

Many of the rhizomes which were dug have dormant buds with
id tips. It is probable that the nematodes cause the injury because
e the tips were infected rotting of the tissues ensue. The thinning
ramie plants at KENRAM may possibly be due to the nematode in-
tion at the growing point of dormant buds.
The control of Meloidogyne incognita with Nemaphos 2E I. Bioassay
concentration gradient. -A. V. Palo and R. H. Califiga.- It was ob-
ved in an in vitro test that about 30 ppm of Nemaphos 2E was suffi-
it to kill the larvae of Meloidogyne incognita Chitwood.
In vivo study under controlled conditions was undertaken to deter-
le the effect of 2 concentrations (16 and 32 ppm) and the influence
varying soil moisture content (11, 16.5 and 22%) on M. incognita.
atment was done by drenching and saturating with the corresponding
es the infested soil (3 parts of clayloam to 1 part of fine sand), con-
ied in 4-inch clay pots. Tomato seedlings of the variety Pearl Harbor
re used as indicator plants and bioassay was carried out after 3
eks from transplanting. Statistical analysis of the data expressed
;erms of number of galls/g of roots showed that at the 3 soil moisture
als, the degree of galling did not differ significantly. Highly signi-
tnt differences were obtained between treatments. At 32 and 16 ppm
roots were almost free of galls, the percentage knotting being 0.17
1 0.41, respectively.
Another test differing from the above in several ways was done
ler field conditions to determine the effect of a wider range of rates
application (1, 2, 4, and 16 ppm). The soil was of the clayloam type
I with a moisture content of 20.5% at the time of treatment. The
S. -1 __ 4- lr nil 1


_________











"il, imjINZ r lYlIUJ


weekly intervals tor a period o t weeKs. Analysis 01 tne aata (gallh
of roots) showed highly significant differences between some of the ti
intervals. It appeared that the number of galls increased from the
to the 2nd week, decreased in the 3rd week, increased again from 1
4th to the 5th week and then decreased again in the 6th week. Hig]
significant differences in number of galls were observed between so
rates. The percentage galling at the rates of 1, 2, 4, 8 and 16 ppm wi
about 80, 59, 59, 59 and 16, respectively.
A third test was done under field conditions also to determine 1
concentration that would give gall-free root system. The rates of ap]
cation tried were 16, 32, 64 and 128 ppm. M. incognita-infested Q
(clayloam with a moisture content of 21% at the time of treatment) v
treated by drenching. After 3 weeks from transplanting, evaluation v
done and the analysis of the data (galls/g of roots) showed highly s
nificant differences between some treatments. The percentage galli
was 0 at 128, 10.5 at 64, 11 at 32 and 77 at 16 ppm.
The control of Meloidogyne incognita with Nemaphos 2E II. T
effect on tomato and the nematode.- A. V. Palo and R. H. Califiga.
The effect of different rates of application (2, 4, 8, 16 and 32 ppm)
Nemaphos 2E on plant height and weight of tops, fruits, and root syst
of tomato and on the root-knot nematode (Meloidogyne incognita C1
wood) was studied. Clay loam soil (with 21.7% moisture content at I
time of treatment) infested with the nematodes and contained in 9-ir
clay pots was drenched with the desired rates. The plants were ki
outdoors and allowed to grow for a period of 11 weeks. Statistical ai
lysis of the data showed that there were no significant differences
plant height between treatments. But significant differences in weij
of tops, fruits and root system were observed between some of the tre
ments at the 5% level of probability. All plants, except those treal
with 32 ppm, exhibited severe root galling. In the check and 2 p]
treatments, the root systems were deteriorating and the plants w(
wilting. Plants in soil drenched with 32 ppm had few and small galls.
Yellow dwarf of rice in the Philippines. M. K. Palomar and C.
Rivera. A disease of rice known as yellow dwarf attributed to a vii
has been observed in the Philippines and more commonly encountered
secondary growth of stubbles. The characteristic symptoms of the d
ease are severe stunting, excessive tillering and general chlorosis
leaves. Reduction in height of infected BPI-76 plants inoculated at
and 30 days old were 51 and 45%, respectively. Both infected plain













culated 60-day old plants showed typical symptoms of the disease
m ratooned.

The virus was transmitted by the green leafhoppers, Nephotettix
licticeps Ishihara and Nephotettix apicales Motsch, within a period
S0 to 37 days and 20 to 35 days, respectively. The minimum inocula-
i feeding period for N. impicticeps was 2-3 min and the minimum
uisition feeding period was 30 min. Based on percentage of infective
,cts, N. impicticeps (83%) seemed to be a more efficient vector than
apicales (69%). Active vectors remained infective until death.
The first reliable symptoms of yellow dwarf appeared on the young-
leaf of Taichung Native 1 within 23-57 days and 34-66 days after
introduction of virus-laden N. impicticeps and N. apicales, respec-
,ly.

Based on symptomatology, vector species, and virus-vector inter-
ion, the yellow dwarf of rice in the Philippines is similar to that
orted in Japan.
Separation of two viruses from sweet pepper. Cridivi S. Pangra-
yen and Ma. Salome E. del Rosario. Sweet pepper plants collected
n the vegetable plot of the Department of Agronomy, U.P. College
Agriculture were observed infected with a mixture of viruses.
The viruses were separated using the following methods: Pure cul-
e of the yellow isolate was obtained after the 7th series of serial
nsfers from single necrotic lesion. It was also obtained when passed
u eggplant and Crotolaria. The green isolate was obtained by isolat-
distinctive green areas and serial transfers from N. glutinosa to
acco, back to pepper and tomato. The physical properties, host range
I symptomatology of each isolate were also studied. Different methods
re devised to separate the mixtures.
Of the 21 species of plants inoculated, 14 were susceptible to the
ates. Eggplant and Crotolaria juncea L. and cucumber were differen-
hosts of the yellow and green isolate, respectively. The virus had the
lowing physical properties: for the yellow isolate, the dilution-end-
nt was 104 with a thermal death point of 70 to 80 C for 10-minute
>osure. The green isolate had a dilution-end-point of 108 and a thermal
Ith point of 70 to 80 C. Both isolates were resistant to chemicals
,h as alcohol (25, 50, 70, 95%) phenol and formaldehyde (1:100,












1:200, 1:500 and 1:1,000 concentrations).
by HN03 at 1:100 and 1:200 concentration
Barley yellow dwarf virus-Cryptomela s
oats. A. C. Pizarro and D. C. Arny. Ass
of Black Hulless (BH) barley and Califor
fungus tentatively identified as Cryptomela
the rhizosphere of healthy CR oats grown in
300 Cryptomela colonies more than those fri
Cryptomela sp. was pathogenic to BH barley
lation of BH barley and CR oats with sporn
did not render them susceptible to Barley Ye
Reactions of BYDV-inoculated BH barley ai
when Cryptomela was inoculated simultaneoi
oculation was delayed by one week. Infectil
Cryptomela combination did not show any
produced by Cryptomela sp. on Waksman's
germination and inhibited root and shoot el
Some ecto- and endo-parasitic nematode,
-A. C. Pizarro, Estela Novero and A. V.
and apparently cadang-cadang affected pal
elected and observed for the presence of plant
scopic examinations of the roots from the
exception of coconut) showed the constant
spp. The second group found feeding ect(
palms (including coconut) was Helicotylencj
served parasitizing roots of two palms (Afi
was another ectoparasite, Criconemoides sp]
Anatomical effects of cadang-cadang <
guelles-Rasa. Cadang-cadang was found to
nut although in severe cases the xylem may
apex did not show any form of necrosis. T.
meristematic activity as revealed by less pi
The water soaked spots (diagnostic charactd
mature leaves showed necrosis and hyperplai
the air spaces were not fully developed.
The soft trunk below the apex was fou
study of the histopathological changes indue
vascular tissue, particularly the phloem. TI
sieve tubes appeared to be obliterated norms


I
lr










ABSTRACTS


phloem and metaphloem sieve tubes were abnormally obliterated few
at a time. As the sieve tubes collapsed the remaining seemingly func-
tional sieve tubes were misshaped. In the site where sieve tubes col-
lapsed the companion or parenchyma cells became hyperplastic. The
hyperplastic cells may also become necrotic and finally break down.
Whether this hyperplastic cells develop into functional sieve tubes were
not fully determined. Due to hyperplasia and collapse of cells, the
phloem lost its normal shape.
Necrosis and obliteration may proceed also towards the remaining
procambium at the center of the vascular bundle so that this tissue be-
comes very disarrange unlike the normal procambium where the cells
were characteristically very regular in shape and size. During severe
infection the xylem may become plugged and the xylem parenchyma also
become necrotic and obliterated.
The phloem distortion produced by cadang-cadang on coconut showed
some resemblance to the anatomical effects of aster-yellows on tomato.
It is highly probable that cadang-cadang may be caused by a virus.
Whether it is of the mosaic or yellows group still requires a very care-
ful study.
A review of the status of Sclerospora philipinensis Weston as a
distinct species. Don R. Reynolds and 0. R. Exconde. Sclerospora
philippinensis Weston, the fungus causing downy mildew of corn, was
established as a species distinct from S. sacchari on the basis of host
and occurrence of sexual spore. A review of available information sug-
gests that the designation of the Sclerospora on corn as a species distinct
from that on sugarcane might not be valid.
Strains .of rice tungro virus. C. T. Rivera and S. H. Ou. During
a 2-year period, 153 rice plants with symptoms of tungro from 15 prov-
inces in the Philippines were tested for possible strains of the virus by
using Nephotettix impicticeps Ishihara as vector. The virus was trans-
mitted by the vector from 141 samples. All but 3 isolates obtained from
Camarines Sur, Iloilo, and Sorsogon caused symptoms typical of tungro
infection in FK-135. These 3 isolates caused stunting but produced no
severe chlorosis or striping in FK-135. However, they produce diagnostic
symptoms on other varieties such as Taichung Native 1, and possess the
biological characteristics of the rice tungro virus. The ability of the
virus to cause striping in FK-135 was used to differentiate 2 strains
of the rice tungro virus. These two strains are designated as "S" and
"M".










'HILIPPINE PHYTOPATHOLOGY

varieties were inoculated with the stripe and non-
varietal differences in symptom expression were
e natural mixture was noted in these 2 strains.
a reaction on host plants was noted between these
protection between strains was noted in the leaf-


ission and physical properties of a coconut cadang-
Cassia occidentalis. -Ma. Salome E. del Rosario
n undescribed mosaic virus on Cassia occidentalis
g-cadang infected coconut palms was studied as
methods of transmission, and physical properties.
nsmitted easily by sap. In vitro studies showed
ble and was easily inactivated after 1 day at or-
*e and 5 days at refrigerator temperature. Longe-
lays at refrigerator and freezing temperatures.
between 1:2,000 and 1:4,000. For 10 minutes at
activated and lost its infectivity in all concentra-
dehyde and phenol but not with nitric acid. The
legume family, typified by Crotolaria anagyroides
s Bak., C. incana I., C. mucronata Desv., Cassia
aureus Roxb.
f this virus isolate with the cadang-cadang syn-

*baca to Pseudomonas solanacearum. Eldon I.
1 1T .- .. -T . . . T . . . 1 _ ..











ARSTRACTS


wvered from these plants. The second isolate from abaca and the
ana isolate produced only limited vascular discoloration extending 5
10 cm from the point of inoculation with no external symptoms. The
cks showed no vascular discoloration. Results indicated that abaca
susceptible to P. solanacearum under Philippine conditions.














THE PATHOLOGICAL AND MYCOLOGICAL HERBARIUM
OF THE UPCA

TRICITA H. QUIMIO AND A. J. QUIMIO

Instructors and Herbarium Curators, 1966-67, Department of
Plant Pathology, UPCA, College, Laguna.
Acknowledgment is due Mr. Don R. Reynolds and Prof. Victoria
M. Ela, for providing some necessary information regarding the
history of the Herbarium.


The nucleus of the first UPCA Plant Pathology collection was
-ovided by Professor Reinking's collections which began in 1917 with
Le founding of the Department of Plant Pathology. In 1919, Mr. E. F.
oldan was appointed Herbarium Assistant to maintain the growing
erbarium. In 1921, Dean C. F. Baker added his valuable assemblage
Some 5,000 fungal specimens from Indo-Malayan area. In late 1930,
ie herbarium which had been named Baker Herbarium after Dean
aker, contained about 25,000 specimens. In addition to the work of
rofessors Baker and Reinking, the collections of E. B. Copeland, F. L.
bevens, W. H. Weston, G. O. Ocfemia and C. G. Wells, were included.
these workers were assisted by the student collectors of the department
id the specimens were documented in Teodoro's "Enumeration of the
hilippine Fungi" (1937).
During that time, duplicate specimens especially those of Reinking
id Baker were distributed to mycologists throughout the world, viz.,
. G. Lloyd, P. A. Saccardo, P. Hennings, W. A. Murril, P. Patouillard,
. Sydow, F. Theissen, T. Petch, F. Petrak, H. Rehm, R. Thaxter, G.
[assee, F. V. Hoehnel, C. G. Ehrenberg, and G. Bresadola. The speci-
ens sent were usually kept in the determiner's personal collection. They
ere then properly identified and a report of the identifications was
*nt to the sender in the Philippines. It was also a practice to record
ie identifications in local literature without identifying the determiner.
i some cases, the determiner abroad, e.g., C. G. Lloyd and P. A. Sac-
irdo. also published a record of the same collection and often named new










-T A -TTT TT- TT h* A


species. Consequently, many of the Baker collections represent type
as the other early collections.
Today, Philippine specimens, including many types and cotypei
are recorded in Ceylon's Royal Botanic Garden, New York Botanics
Garden, USDA National Fungous Collections, Farlow Herbarium, Un
versity of North Carolina Herbarium, Kew Herbarium, Leiden's Rij1
sherbarium, and Paris' Museum of Natural History.
During the second world war, the Baker Herbarium was destroy
and only professional foresight saved the fruits of long years of mycol<
gical effort. Recovery after the war was slow. In 1948, Dr. G. O. Ocft
mia arranged for a gift of duplicates plus an exchange of several hur
dred specimens from the USDA National Fungous Collections. Tl
specimens included those from the Baker Herbarium sent to the U. S
before the war. Dr. Ocfemia also arranged for Jenkins and Bitancoul
exsiccata of Elsinoe and Sphaceloma but which was incompletely re
ceived. Dr. Ocfemia continued to collect fungi, but later became ii
terested in research on abaca mosaic. Dr. F. T. Orillo named sever;
species of Helminthosporium and his many other researches contribute
much to the mycology program of the department.
The offering of a mycology course (PP 204) to graduate student
by M. O. San Juan in 1957 stimulated interest in the herbarium. C
returning from Wisconsin in 1962, Dr. San Juan offered an undergrai
uate introductory mycology course (PP 140) and split the gradua'
course into 2, PP 220 and PP 221. These courses required students 1
collect and submit specimens which added to the slowly-growing he
barium.
The collections of D. R. Reynolds in many parts of the Philippin,
from 1963 to 1967, increased the department's collections. The collection
of Agaricales from Mt. Maquiling by A. J. Quimio and his students
PP 140, and the pathological specimens required of PP 11 and PP 1(
students, swelled the herbarium even' more. The advanced students
Reynolds' PP 220 and PP 221 contributed to the mycology program ai
the herbarium with studies on higher fungal groups. The studies i
cluded the Gasteromycetes by S. P. Hsieh; Marasmius and Mycena 1
Fe Divinagracia; Coprinus by A. J. Quimio; Hysterium by R. V. Cc
tado; Phyllachora by S. D. Dalmacio; PhyUosticta by H. Ahmid; Oidiv
by Q. Zahman; Lepiota by F. L. Nuque; Panus and Lentinus by H.
Hsu; Hypocreales by A. M. Era; Pleurotus and Schizophyllum by H.
I I - -- ---I- U-T T 'n- a Tr




























commended 50 mycological and pathological journals and 9 mycological
textbooks (Korf, 1966), all of which have been purchased by the UPCA


m the UP-Cornell Gradi
equipment to house the
ets and a filing cabinet,


Organization: Each specimen has 3 accession cards for cross index-
ing, as arranged under the Dumont Plan. The file arrangement is by
number, by binomial, and by host. The specimens are filed in the draw-
ers of the herbarium cabinets by numerical order. Each packet (or box
or jar) containing the specimen bears a label showing the accession




























o -ou -%U urLAu CumI Ie1u 01 yu1TI 'ywrI L
4512 4517 Payawal collection of Asterina
4518 4533 Era collection of Hypocreales


is been designated by the
ny as CALP (College of A
be listed in the next edil


:her cc

sent f
iciatiox











HILIPPINE rHYTOPATHOLOG0


Since the Baker Herbarium was destroyed during the war, it is
proposed that the present collection deposited at the Department of
Plant Pathology be known as the Ocfemia Memorial Herbarium. This
is a fitting tribute to the late Dr. Gerardo O. Ocfemia (1891-1959) who
was the first Filipino chairman of the Department of Plant Pathology,
an active contributor, and was instrumental in the beginning of a new
assemblage of Philippine fungi (Ela, 1965).




LITERATURE CITED

ELA, VICTORIA, M. 1965. Gerardo O. Ocfemia, 1891-1959. Phil. Phytopatho-
logy 1:5.
KENT, G. C. 1965. Report of the Consultant in Plant Pathology. Ford Founda-
tion-Sponsor, U.P. -Cornell Graduate Education Program, UPCA, College,
Laguna. 68 p. (Mimeographed).
KORF, R. P. 1966. Report of the Visiting NSF-Supported Professor of Mycology,
UPCA, College, Laguna. 25 p. (Mimeographed).
TEODORO, N. G. Enumeration of Philippine Fungi. Tech. Bull. 4. DANR.
Commonwealth of the Phil. 585 p.















YELLOW DWARF OF RICE
IN THE PHILIPPINES

M. K. PALOMAR AND C. T. RIVERA

Research Assistant and Assistant Virologist, International Rice
Research Institute, Los Bafios, Laguna.
This investigation was supported in part by Research Grant 2.68
from the National Science Development Board of the Philippines.

The authors thank Dr. K. C. Ling, Associate Plant Pathologist,
IRRI, for his valuable comments and suggestions.

ABSTRACT

The virus which causes the yellow dwarf of rice was trans-
mitted by the green leafhoppers, Nephotettix impicticeps Ishihara
and Nephotettix apicalis (Motsch.) within a period of 20 to 37 days
and 20 to 35 days, respectively. The minimum acquisition feeding
period was 30 min while the minimum inoculation feeding period
for N. impicticeps was 2 to 3 min. The percentage of infective in-
sects was 83 for N. impicticeps and 69 for N. apicalis. Active vec-
tors remained infective until death.
The earliest characteristic symptoms of yellow dwarf appeared
23 to 57 days and 34 to 66 days after introducing virus-laden N.
impicticeps and N. apicalis, respectively. This was noted on the
youngest leaf of Taichung (Native) 1. The symptoms observed in
this variety were more pronounced than those in BPI-76 and infected
plants failed to produce panicles.

The height of infected BPI-76 plants was reduced by 51% and
45% when inoculated at 10- and 30-day old, respectively. In either
case, infected plants produced more tillers and panicles but failed to
yield fertile grains. Inoculated 60-day old plants showed typical
symptoms of the disease when ratooned.
Based on symptomatology, vector species, and virus-vector inter-
action, the yellow dwarf of rice in the Philippines resembles that
reported in Japan under the same name.



Rice plants characterized by severe stunting, excessive tillering,
nd general chlorosis were observed at IRRI experimental plots in 1962

27














on symptoms and transmitting insects (IRRI, 1963) revealed that t]
plants were affected by a virus disease similar to the yellow dwarf r
ported in Japan (Shinkai, 1962).

Yellow dwarf has been extensively studied 4y Japanese work
since it was first reported in 1919. This disease also occurs in Taiwa
South China, Ryukyu Island, Thailand, Malaysia, Ceylon and Ind
(Abeygunawardena, 1967; Ou and Rivera, 1967; Raychaudhuri et a
1 Q '7. 1 .,1 1XT7 _____4- Inlr7\ -, -- __ !_ .1. Tm


mission of yellow dwarf; 2) collect information on the gi


m JaDan.


The green leafhopp(
black-streaked green leal
used as vectors. Test pla:
3 in the transmission e:
growth and yield studies

To determine the i
nymphs were caged on in
each day to a series of I
in a test tube until they
ways one day, unless oti

Following acquisition
hr and an incubation pe
were confined singly on
insects were allowed to f
and 60 min to determine

Plant height was mi
were counted before inoc
BPI-76 plants at 10,
vidually with 2, 6, and 1(


on rice seeanngs tor z to 3
e minimum inoculation feedir

ared and the number of lea
tion and periodically thereaft


rulife


lU, 10,
period.

and til


ulated ii
ri.-


inqpati-














Pw11ig bylrIyLuIrli ui meL ulsasee were note


parated from empty ones and their number and weight were taken.
colored seeds from infected plants were compared with those of
3 healthy controls.

RESULTS AND DISCUSSION

Transmission. Rice yellow dwarf virus was transmitted by N. im-
cticeps within a period of 20 to 37 days (usually 20 to 26 days) and
N. apicalis within 20 to 35 days (usually 22 to 27 days) after ac-
isition feeding. In serial transfers, both species generally failed to
fect each of the seedlings to which they were transferred daily but
impicticeps had more positive transmission in all serial transfers
allowing the completion of the minimum incubation period of 20 days;
e opposite was true for N. apicalis. In all tests, N. impicticeps had a
gher percentage of infective insects (83%) than N. apicalis (69%).
ie leafhoppers remained infective until death (Fig. 1).
The minimum inoculation feeding period for N. impicticeps was
to 3 min and the minimum acquisition feeding period was 30 min.
under such a relatively short inoculation feeding period, the infective
sects can transmit the virus to healthy plants before insecticides can
11 them.
Adult female and male N. impicticeps can equally transmit yellow
varf. The percentage of transmission, incubation period, number of
fected seedlings per insect, and retention period of infective adults
'e given below as means and ranges:
Infective Incubation Retention No. of infected
adults (%) period (days) period (days) seedlings/insect
23 9.9 7.9
'male 81.1 (20-36) (1-32) (1-27)
23 8.8 7.3
(20-34) (1-26) (1-24)
he female insect retained the virus for a longer period than the male
-obably because of its longer life span. As observed in the leafhopper
I L 1 ..i . . 1 .3- . 2 -











PHILIPPINE PHYTOPATHOLOGY


Symptoms. The first characteristic symptoms of yellow dwarf a
peared on the youngest leaf of Taichung (Native) 1 plants 23 to
days (usually 30-46 days) and 34 to 66 days (usually 34-48 days) aft
in the introduction of virus-laden N. impicticeps and N. apicalis, r(
pectively. As the disease progressed the entire leaf turned from lig
green to yellow green.
Further disease development was characterized by the narrow:
and shortening of the new leaves and stunting of the plant. Leaf d
coloration varied from yellow-green to greenish-yellow. Excessive till
production generally followed. Infected plants produced as many as 1
tillers while the healthy control produced only about 18.
Infected plants never recovered. They rarely produced panicli
When the incubation period of the virus in the plant was prolonged
two months, stunting was not severe and panicles were produced I
the spikelets were mostly aborted and reduced in size.
Growth and yield. The reduction in height of infected BPI-76 plain
inoculated at 10 and 30 days of age were 51% and 45%, respective
(Fig. 2). These infected plants produced more tillers and panicles I
yielded no grain. Plants inoculated at 10 days of age had slightly m(
leaves, whereas 30-day old inoculated plants produced the same numl
of leaves as the control plants. Some of the BPI-76 plants inoculal
at 60 days of age showed yellow dwarf symptoms only when ratoon
In such cases, the growth and yield of the infected plants were ab(
the same as their healthy counterparts.
Within the limit of the incubation period of the virus in the ph
which must be completed before harvest, the rice plant is suscepti
to yellow dwarf and is, therefore, a potential source of the virus throul
out its life. When inoculated at a later stage, symptoms of the dise;
may not be apparent before harvest. This corroborates the results
tainted by Shinkai (1962) who reported that yellow dwarf appeared
ratoons when plants were inoculated at the 16-leaf stage.
Table 1 compares yellow dwarf of rice in Japan with that in
Philippines. The disease in either country has a high percentage
active insects, short acquisition and infection feeding periods, and a cc
paratively long incubation period.
N. cincticeps is not known to occur in the Philippines and is, the
fore, not included as a test insect.












I III 11III 1


50

Acquisition "
n, Feeding "
5 40 -
0


j30 0


20



10

o ,----- ,\- i
0 i
0 5 10 15 20 25 30 35 40
No. of Days






Nephotettix impicticsM

I-I Non-infective
i Infective (?)
a- Infective


Acquisition I
Feeding
*0

0














A 71 p
'ON"13,,,. . , I ; "Imst 1 A" 1, 0
'APO
All, 1; i 110-ii"A











YELLOW DWARF


TABLE 1. Comparison between yellow dwarf virus disease of rice in Japan and
in the Philippines.

Items Philippines Japana

Vector Nephotettix impicticeps Nephotettix impicticeps
Ishihara Ishihara
N. apicalis (Motsch.) N. apicalis (Motsch.)
N. cincticepsb (Uhler)
Active insects (%) 83; 69 80
Minimum acquisition
feeding period 30 min 30 min
(N. impicticeps)
Minimum infection
feeding period 2-3 min 1-3 min
(N. impicticeps)
Incubation period (days)
Insect 20-27 25-30
Plant 30-48 30-90

aShinkai, 1962.
b Species not found in the Philippines.



In most cases, yellow dwarf is more commonly observed on the
secondary growth of tillers from stubbles. This may be due to the long
incubation period (about 30 days) required by the plant and the vector.

In view of the above, yellow dwarf is considered to be of minor
importance in spite of its wide distribution. However, if ratoon crop-
ping is extensively practised in the Philippines, this disease may become
a major problem.













PHILIPPINE PHYTOPATHOLOGY


LITERATURE CITED


ABEYGUNAWARDENA, D.V.W. 1967. The present status of virus disease- of
rice in Ceylon. Paper presented at the symposium on virus diseases of the
rice plant, April 25-28, 1967. IRRI, Los Bafios, Laguna, Philippines. (In
Press) .

INTERNATIONAL RICE RESEARCH INSTITUTE. 1963. Annual Report 1961-
1962. Los Bafios, Laguna, Philippines. 199 p.

OU, S. H. and C. T. RIVERA. 1967. Virus diseases of rice in Southeast Asia.
Paper presented at the symposium on virus diseases of the rice plant, April
25-28, 1967. IRRI, Los Bafios, Laguna, Philippines. (In Press).

RAYCHAUDHURI, S. P., M. D. MISHRA, and A. GHOSH. 1967. Occurrence of
paddy virus and virus-like symptoms in India. Paper presented at the sympo-
sium on virus diseases of the rice plant, April 25-28, 1967. IRRI, Los Bafios,
Laguna, Philippines. (In Press).

SHINKAI, A. 1962. Studies on insect transmission of rice virus diseases in Japan
[In Japanese, with English summary]. Bull. Nat. Inst. Agr. Sci. (Ser. C.)
14, p. 28-54.

WATHANAKUL, L. and P. WEERAPAT. 1967. Virus diseases of rice in Thai-
land. Paper presented at the symposium on virus diseases of the rice plant,
April 25-28, 1967. IRRI, Los Bafios, Laguna, Philippines. (In Press).















VIRUS DISEASES OF WEEDS IN THE PHILIPPINES
II. PHASEOLUS LATHYROIDES MOSAIC

MA. SALOME DEL ROSARIO, O. R. PAGUIO, AND D. A. BENIGNO

Research Associate Professor, Research Instructor, and Instruc-
tor, respectively, Department of Plant Pathology, U.P. College of
Agriculture, College, Laguna.
This work is a part of the research grant supported by U.S.
Public Law 480, FG-102, U.S.D.A.

ABSTRACT

Phaseolus lathyroides mosaic virus (PLMV) is transmissible by
sap, aphid&, and through the seeds. Studies on its physical proper-
ties revealed that it is inactivated by 50% alcohol and 1:100 phenol
and by aging (72 hours) in extracted sap at room temperature. Its
dilution end-point is 1:1000 while its thermal inactivation point lies
between 60 and 67 C for 10 min.
Its host range is limited to the legume family. Based on its
physical properties and host range PLMV belongs to the bean mosaic
group.


Phaseolus lathyroides Linn., a legume green manure crop, is a very
common weed in the field. More often than not this plant is infected
with a mosaic disease.
The first symptom of naturally-infected plants is the net-like vein
clearing of the youngest infected leaves (Fig. 3). Later the plants ex-
hibit chlorotic yellow spotting interspersed with island of green patches.
Terminal shoots droop and young leaves curl inwards. In severe cases
terminal shoots tend to elongate producing fern-like leaves. The chlo-
rophyll bodies in the shoots are wanting and the leaves are yellow in
appearance (Fig. 1).

Because of the abundance of this weed in the field and its suscep-
tibility to virus infection, this investigation was undertaken to know the
nature of the causal virus and to find out whether it is transmissible
to coconut and other plants.











4ILIPPINR PHVTrnPAT-T Tr-.v


i 10 thin-walled test tubes.. These were heated for 10 min in a water
ith at temperatures ranging from 40 to 90 C at 10-degree intervals.


RESULTS AND DISCUSSION























Fig. 1. Phaseolus lathyroides Linn. exhibiting mottling, distortion z
young leaflets and reduction in size.


















Fig 2 Differences in os exhibited ba
Fig. 2. Differences in symDtoms exhibited by infected plants.


I ".

























FrG. 3. Differences in symp- on P. lathyroides. 3. Vein-clearing and mild
tom patterns. 2. Vein-clearing and mild mottling on Vigna si-
1. Net-like vein clearing mottling on P. lunatus. nensis x Vigna sesqui-
pedales.


\d


e


FIG. 4. Differences in symptom pattern on different plants.
a. Gomphrena globosa -diffused yellowing from midrib toward the leaf blade,
(still doubtful under study).
b. Soja max vein-clearing associated with dark green islands on the light
green to the yellowish leaf.
e. Centrosena pubescens vein-clearing.
d. Vigna sineniis cv. Capiz prominent vein-clearing and mottling.
e V. sinem.si str. # 5 prominent vein-clearing.
f. P. rulgari. cv. Bountiful (white) necrotic brown spots.






















VIXUI) Ulzlzabrlb Ur Wl!'IU)


C \'L Llil~ ~UIYU UVlllrYII~CLI1 V1~- UII~UV~U rlUIIUU U~~Llllr LICL












PHILIPPINE PHYTOPATHOLOG


Vin sinensis (cv. Sin ore and c. Dumauete).-The symptom
Vinnan. sinensig (cv. SinvaDore and cv. Dumaguete).-The symptor













VIRUS DISEASE OF WEEDS


The three criteria used for identifying this virus give us a working
knowledge on the probable identity of the virus.

By comparing the Phaseolus lathyroides mosaic virus (PLMV),
with the bean mosaic virus (BMV), bean yellow mosaic virus (BYMV),
bean (southern) mosaic virus (BSMV), on the basis of the three criteria
mentioned above, it seems that the virus causing mosaic on P. lathyroides
is a bean mosaic virus rather than BYMV or BSMV because of its in-
ability to infect Pisum sativum (Table 1).


TABLE I. Comparison of Phaseolus lathyroides mosaic virus with.
viruses.


known bear


The Viruses


Basis of Comparison


PLMV BMV


BYMV BSMV


I. Transmission
1. By sap
2. By aphids
3. By seeds

II. Host range
1. Phaseolus aureus
2. P. lunatus
3. P. vulgaris
4. Pisum sativum
5. Soja max
6. Vigna sinensis
7. Vigna sinensiss x
sesquipedalis)
8. Centrosema pubescens
9. Crotalaria incana

III. Physical Properties
1. Longevity in vitro

2. Dilution end-point

3. Thermal death point
4. Resistance to Chemicals
Alcohol
Phenol


72 hrs. 24 to 24 to
32 hr 32 hr
1:1000 1:1000 1:800
1:1000
60-67 C 56-58 C 56-60 C


50%
1:100


25-50%


32 wk

1:500,000

95 C

95%
















FUSARIUM HEAD BLIGHT OF WHEAT

O. R. EXCONDE, C. M. NAPIERE AND F. D. FUENTES

Respectively, Assistant Profe-sor, Undergraduate Thesis Student,
and Instructor, Department of Plant Pathology, U.P. College of
Agriculture, College, Laguna.

A STRACT

Fusarium head blight appears on the edge of the glumes, lemma
and palea as water-soaked pinkish yellow to purple brown minute
spot about the size of a pin head. These spots enlarge and assume
circular to irregular areas. When conditions are favorable, whiti h
to pinkish mycelial growth covers the entire head. Consequently.
the head becomes bleached and finally turns straw-"olored As the
disease progresses, the palea, lemma, and glume are pasted together
with the mycelial mat of the fungus. Severely infected head: topple
over.
The disease is caused by Fusarium roseum (Cke.) Snyder and
Hansen.
Burning of stubbles after harvest and planting of resistant varie-
ties such as Giza 148, Fylgia, Fiorello, T-31, T-32, NP-720, NP-7!)8,
NP-823, and C-281 are recommended control mea-ures.


One of the serious diseases of wheat (Triticum aestivum L.)
Fusarium head blight. The disease attacks the head and kernels
sulting in premature ripening or drying. Consequently, there is a c
siderable dicrease in yield of the crop. This disease was first reDor
in Europe by Detmer (1892) and in the United States by Arthur (18!
and later by Adams (1921). Butler and Jones (1949) reported tl
Gibberella or Fusarium head blight of wheat is caused by either G
berella zeae (Schw.) Petch or Gibberella saubinetti (Mont.) Sacc.

Atanasoff (1920) reported that head blight of cereal crops is g
erally known under the faulty name "wheat scab". He believed t]
the name scab is not proper because of the absence of the scab on
head. He suggested that the disease should be called head blight.
AlfthnilliA l irxlt- ixrTQa i"nrlr.v onlfirmfinI in M +- PDhlurn-- on no













s 1664 (Uichanco, 1931), no occurrence of this disease has so far been
recorded. Recently, however, head blighting of wheat has been noticed
i the field trials at San Mateo, Isabela; Dingras, Ilocos Norte; and in
os Bafios, Laguna at the Central Experiment Station and the B.P.I.
economicc Garden. This paper presents the diagnostic symptoms of the
disease and the morphological, cultural, and some physiological charac-
eristics of the causal fungus.

MATERIALS AND METHODS

The fungus was isolated by tissue planting from infected glumes
Allected from the field at the Central Experiment Station, College,
aguna. Isolates thus obtained were tested for their pathogenicity. In
ests of pathogenicity, seeds and plants at various stages of development
'ere inoculated with the isolates. In all experiments, wheat variety
Feveh Yaar was used.

Four methods of inoculation were employed. The first consisted of
)ray-inoculating wheat heads at dough stage with spore and mycelial
ispension. In the second, plants at booting stage were infected with
pore and mycelial suspension below the flag-leaf. In the third, 10-day
Id seedlings were spray-inoculated with spore and mycelial suspension.
i the fourth, previously disinfected seeds were planted in artificially
ifested soil by mixing 9-day culture on corn meal-sand medium with
utoclaved soil at 1:3 ratio. In the first three methods, all inoculated
[ants were incubated under plastic or bell jar covers. In all instances,
isolates were obtained from infected tissues of the artificially-inocu-
Ited plants. Reisolates thus obtained were maintained on PDA and
sed in subsequent studies on the morphology, physiology, and cultural
maracters of the fungus.
The effect of 11 agar media and pH on the mycelial and conidial
development of the fungus was studied. Conidial germination was tested
n tap water, distilled water, and nutrient broth in van Tieghem cells
nd on thin layers of PDA on sterile glass slides which were incubated
1 petri dishes lined with moist filter paper.
Suscept range was determined by inoculating related plants in the
familyy Gramineae. Inoculation was done by either spraying or inject-
ig spore and mycelial suspension at booting and heading stages. In-
rninftril nln+a rora ithvor eporPol with nlastic bac or keDt inside in-


-1-1 .- - __ - ~0 1111~













cubation chamber for 24 to 48 hr. Control plants in every case we
provided.
Longevity of spores in dry and steamed soil. Infected heads pr
duced after inoculation were collected and air dried. They were divide
into 2 lots. The first lot was incorporated with steamed soil contains
in clay pots and placed inside the greenhouse throughout the expel
ment; the second lot was incorporated with the same soil but kept ot
doors. The viability of the spores was tested at weekly intervals 1
germinating them in sterile distilled water in van Tieghem cells or
a thin layer of PDA on sterile micro-slides. They were incubated f
12 to 24 hr. Spores that failed to germinate after 24 hours were co
sidered non-viable.
Varietal resistance and susceptibility. Thirty-two promising whe
varieties were inoculated at heading stage by spraying them with spo
suspension and subsequently incubated for disease development. Tv
weeks after inoculation disease reactions were rated as resistant-i
apparent symptoms on head; intermediate-one-half of the head i
fected; and susceptible-entire head infected.

RESULTS AND DISCUSSION

Symptomatology. In all inoculation experiments in the above
ground parts of wheat, there was a consistency of symptom expression
The earliest symptom appeared on the edge of the glumes, lemma ai
palea as water-soaked pinkish yellow to purple brown minute spo
about the size of a pin head. These initial lesions turned brownish wii
light yellow border. Soon these spots enlarged and assumed circular
irregular areas. Under favorable conditions, whitish to pinkish myceli
growth covered the entire head. Consequently, the head became bleach(
and finally turned straw-colored. As the disease progressed, the pale
lemma, and glume were pasted together with the mycelial mat of tl
fungus (Fig. 1). In a few cases, severely infected head topples over.
Test of pathogenicity. By spray-inoculating wheat heads at doug
stage with spore and mycelial suspension of the fungus, symptoms al
peared as water-soaked, pinkish yellow to purple-brown spots on tl
glumes 7 days after inoculation. Soon, whitish to pinkish myceli
growth covered the glumes, lemma and palea and pasting them together
Seeds harvested from infected head were shrivelled and light. Whe

























FIG. 1. Healthy (left) and diseased head
(right) of wheat. Note the cot-
tony mycelial growth envelop-
ing the grains.


a. ~a~a


I I ~ IB~











'HILIPPINE PHYTQPATHOLC


FIG. 3. Characteristic growth of Fusarium roseum on various agar me-
dia after 7 days: a) onion agar; b) V-8 juice agar; c) lima
bean agar; d) malt extract agar; e) oat meal agar; f) nutrient
dextrose ag.ar; g) nutrient agar; h) Czapek's agar; i) potato
dextrose agar; j) water agar and k) corn meal agar.













t4Ez, rvall3 p I IoLiL ic ial givVL appJalcuL LG UnII Lil 1IUIL VIVlui
iter became rotted. In a few cases, inoculated heads failed to emerge
rom the leaf sheath. On seedlings sprayed with spore and mycelial
ispension, water-soaked lesions appeared at the base of the culm 48
ours after inoculation. Within 4 days later, infected seedlings com-
letely wilted and toppled over. Disinfected seeds sown in artificially
ifested soil were not infected by the fungus even for a period of 2
months.
In all inoculation experiments, all the control plants remained
healthy throughout the period of observation.

Morphology of the Causal Fungus

Mycelium. Hyphal threads are hyaline, septate, sparingly branched,
lin-walled and finely granular when young; becoming vacuolated and
iick-walled when old. Hyphal cells from 7-day culture on PDA ranged
rom 81.9 to 82.6 u long and 3.4 to 7.2 u in diameter.
Conidiophore. Conidiophores are borne singly on the hyphae. They
re short, hyaline, non-septate, branched or unbranched in a few cases,
ranular when young, vacuolate and thick-walled with age (Fig. 2).
onidiophores from 10-day culture measure from 8.7 to 52.1 u long
nd from 2.6 to 5.2 u in diameter.
Conidia. Microconidia are hyaline, subspherical or ovoid and non-
eptate when young; with age, they become granular, thick-walled and
eptated. They are borne singly or in cluster at the tip of conidiophores.
[icroconidia from 10-day culture measure from 5.2 to 24.1 u and from
.4 to 8.3 u in diameter. Macroconidia are long slender, sickle shaped,
righth, sometimes curved, tapered at both ends, hyaline and usually
-septate; borne singly at tip of conidiophore. With age, they become
lick-walled. Their size ranged from 22.4 to 101.4 x 2.6 to 4.5 u.
Cultural Characteristics. Growth characteristics on 11 agar media
re summarized in Table 1 and illustrated in Fig. 3.
Effect of temperature on growth and sporulation. The optimum
temperature range was between 20 and 28 C; the minimum was 12 C
nd the maximum was 32 C. No growth was observed between 4 and
C and bhtwppn 6R and 40 C. Very abundant snores formed at tempe-













PHILIPPINE PHYTOPATHOLOGY


C. Subsequent studies of Dickson (1923) showed that sparse mycelium
developed on acidified agar at 8 C with optimum growth at 28 C; on
non-acidified agar optimum growth was at 24 C and little or no growth
occurred between 32 and 34 C.


TABLE 1. Growth characteristics and conidial
various agar media.


production of


Fusarium roseum on


Media


Czapek's
solution agar


Onion agar






Potato-
dextrose agar






V-8 juice
agar





Nutrient
dextrose
agar


Growth
Characteristics

Mycelium fairly abun-
dant, pale ochraceous
salmon to medium pale
cinnamon pink after 2
days. Mycelium became
compact and turned
white to salmon after
6 days.

Mycelium slightly sub-
merged. Medium be-
came buff pink after
2 days. White to pink
mycelial growth became
dull gray after 5 days.

Mycelial growth cot-
tony white to pinkish
in color. Culture me-
dium became dull bluish
violet at the center and
pinkish buff after 5
days.

Mycelium submerged.
Very few aerial
growth. Medium french
gray after 2 days, and
pallid purplish gray
after 5 days.

White mycelial growth
became medium ochra-
ceous salmon after 2
days, changes to pale
ochraceous buff with
dull gray margin after
5 days.


Production
of Conidia

Very
abundant


Diameter of
Colony in mm.
After 7 daysa

84.2


Very
abundant


Very
abundant






Scarce






Very
abundant


80.6








82.7






80.0













FUSARIUM HEAD BLIGHT OF WHEAT


TABLE 1. Growth characteristics and conidial
various agar media.


production of


Fusarium roseum. on
(Continued)


Growth
Characteristics


Nutrient
agar






Water agar





Lima bean
agar







Oatmeal
agar





Malt extract
agar






Corn meal
agar


Media


Diameter of
Colony in mm.
After 7 days


Production
of Conidia


Very
abundant






Scarce





Very
abundant







Very
abundant





Very
abundant






Very
abundant


a Average of 3 plates.


Few aerial white my-
celia. Medium became
pale olive gray after 2
days and changed to
martius yellow after 5
days.

Submerged mycelia
pale gray after 2 days.
No change in color of
medium after 4 days.

Few aerial white my-
celial growth. Medium
rosalene pink after 2
days and changed to
amaranth purple with
pale pink margin after
5 days.

Few aerial mycelial
growth. Culture me-
dium became pale yel-
low with pale dull gray
margin after 5 days.

Submerged white my-
celium. No change in
color of medium after
2 days but became pale
brownish venaceous to
dull gray after 5 days.

Submerged white my-
celial growth. No
change in color of cul-
ture medium after 5
days.


62.2







62.5





83.7









79.6






85.7







86.6


~~ ____












PHILIPPINE PHYTOPATHOLOGY


TABLE 2. Growth and conidial production of Fusarium
ferent hydrogen-ion concentrations.


roseum on PDA with dif-


Abundance of
pHMycelium Cnidia
Mycelium Conidia


Diameter of
colony in mm
after 6 days


3 Fairly abundant
4 Abundant
5 Very abundant
6 Very abundant
7 Very abundant
8 Very abundant
9 Very abundant
10 Very abundant
11 Abundant


Fairly abundant

Very abundant
Very abundant
Very abundant
Very abundant
Very abundant
Very abundant
Very abundant
Scarce


a Average of 4 plates.


Effect of pH on mycelial and conidial development. Growth charac-
teristic of the fungus on 11 pH levels are presented in Table 2 and illus-
trated in Fig. 4.

Conidial germination. Conidia germinated within 9 hr on PDA,
18 hr on tap water, 21 hr on distilled water, and 15 hr on nutrient broth.
Manner of conidial germination was generally by the formation of polar
hyaline germ tube. In a few cases, 2 germ tubes were formed on both
ends (Fig. 5).

Viability of spores in plant debris. The conidia of the causal fungus
in plant debris remained viable for 6 months in the greenhouse and for
only 5 months when kept outdoors. Butler and Jones (1949) found that
conidia of G. saubinetti could live under dry conditions for as long as
7 months.

Suscept range. Among 10 species tested by repeated inoculation,
the fungus infected only 5; these were rice, corn, oats, sorghum, and
Eleusine indica. Those uninfected were Cyperus kyllingia Endl., Echino-
chloa colonum (L.) Link, Leptochloa panica (Retz.) Chur., Paspalum
conjugatum Berg., and millet [Eleusine coracana (L.) Gaertn.]. McInnes


33.0
49.3
76;.5
77.3
80.5
81.5
80.7
77.5
62.2












FUSARIUM HEAD BLIGHT OF WHEAT


FIG. 4. Effect of indicated pH on growth of Fusarium roseum.





































4 I. -a -








FrI. 5. Photomicrograph of germinated micro and macroconidia of
Fusarium rosezum (x 800).













and Raymund (1923) reported that the wheat scab fungus could infect
oats, rye, corn, and a number of other grasses.
Varietal susceptibility and resistance. After repeated inoculation,
the wheat varieties categorized as susceptible are Neveh Yaar, Florence
aurore, C-591, Argentine I, Festival, B-256-G, Akakahoba, Akakamuga,
FXA 188-67, Fortunato, and Florida; those resistant are Giza 148, Fyl-
gia, Fiorello, T-31, T-32, NP-720, NP-798, and C-281; those in the inter-
mediate category are Cross-3, NP-12, NP-52, NP-718, NP-758, NP-797,
Hindi-O, Damiano chiase, Etiole de Hoise, Hoshangabad, Spica, Binya,
and H-68.

Identity of the Causal Fungus

In Snyder and Toussoun's (1965) system of classifying Fusarium
species, the causal fungus in this study is identical to Fusarium roseum
(Cke.) Snyder and Hansen, except that it formed no chlamydospores.
According to Snyder and Toussoun (1965) there are several clonal lines
within F. roseum in which chlamydospores are absent. It is considered
that the fungus under study is one of these several clonal lines. In a
personal communication with Dr. William C. Snyder of the University
of California at Berkeley, the identity of this causal fungus was con-
firmed as such.

Seasonal Occurrence and Saprogenesis

Observations made on the wheat trial plantings at the Central
Experiment Station and the B.P.I. Economic Garden at Los Bafios,
Laguna, revealed that the disease appears as early as October. It be-
comes severe when warm and moist conditions prevailed during the
growing season. This observation substantiates the report of Dickson
(1923) and Johnson and Dickson (1921) that the disease causes damage
to wheat especially during heading or blossoming periods when the tem-
perature and relative humidity are high. McInnes (1920) found that
high percentage of wheat head became blighted when temperature at
the time of their emergence from the sheath was 24 C.
Saprogenesis. Infested plant debris left in the field after each har-
vest was found to contain abundant spores and mycelium of the fungus.
These fungous organs remain viable from 5 to 6 months in the soil with
AahriT nf infPoaorl n1Rnta





















iiarveUL WUuIU reuuce Ln aouurUe ui mIlocuMiu ,a'"LsOftU Ztrctwu i,-nu uer
tain other grasses should not be allowed to grow with wheat because
they are potential hosts for the fungus. Differences in varietal reaction
to the disease points to the planting of resistant varieties such as Giz,
148, Fylgia, Fiorello, T-31, T-32, NP-720, NP-798, NP-823, and C-28
as one of the measures of control.





LITERATURE CITED

ADAMS, J. F. 1921. Observation on wheat scab in Pennsylvania and it. patholk
gical history. Phytopathology 11: 115-124.
ARTHUR, J. C. 1891. Wheat scab. Indiana Agr. Expt. Sta. Bull. 36, p. 129-13'
ATANASOFF, D. 1920. Fusarium blight (scab) of wheat and other cereals
J. Agr. Res. 20: 1-32.
BUTLER, E. J. and S. J. JONES. 1949. Diseases of cereals. In Plant Pathc
logy. MacMillan and Co., Ltd., London. 979 p.
DETMER, F. 1892. Scab of wheat. Ohio Agr. Expt. Sta. Bull. 44, p. 147-149
DICKSON, J. G. 1921. The influence of soil temperature on the development c
seedling blight of cereals caused by Gibberella saubinetti (Mont.) Sacc. Phyt(
pathology 11: 35-36.
DICKSON, J. G. 1923. The influence of temperature and moisture on the deve
opment of seedling blight of wheat and corn caused by Gibberella saubinet
(Mont.) Sacc. J. Agr. Res. 23: 837-870.
JOHNSON, A. G. and J. G. DICKSON. 1921. Wheat scab and its control
U.S.D.A. Farmers Bull. 1224, 16 p.
McINNES, J. 1920. The effect of temperature and light on Fusariumn spp. causin
wheat scab. Phytopathology 10: 52.
McINNES, J. and F. RAYMUND. 1923. Wheat scab in Minnesota. Minn. Agr
Expt. Sta. Tech. Bull. 18, 32 p.
SNYDER, W. C. and T. A. TOUSSOUN. 1965. Current status of taxonomy i
Fusarium species and their perfect stages. Phytopathology 55: 833-837.
UICHANCO, L. B. 1931. Historical notes on the cultivation of wheat in th
Philippines. Philippine Agriculturist 20: 239-245.



















AS THE RAW MATERIALS

LOURDES C. IGNACIO AND R. V. ALICBUSAN

Undergraduate thesis student and Instructor IV, respectively,
Department of Plant Pathology, U.P. College of Agriculture,
College, Laguna.

The authors express their thanks to Mr. Renato D. Perez of
the Berbacs Chemicals, Inc. for providing magne yeast, and to Mrs.
Victoria G. Hernandez of the Department of Agricultural Chemis-
try for making the appropriate analysis of the distillate samples.


parative study on the alcohol pr
__ I


from molasses was


The alcohol obtained
molasses were 91.17% fo
champagne yeast.

The amount of acet,
9.65 for magne, 21.71 f(
Yeast cells obtained :


sed on fermental
agne, 86.21% foi


tyde in mg per
,1_. ._3o n -A .


ars present in
and 81.5% for


distillate was
agne.
Measured 8.4


ute the branch o:
ities through th


rescott and Dunn (195!
such as rapid growth, :


e criteria of good distillery
sugar tolerance, efficiency











PHILIPPINE PHYTOPATHOLOGY


in the conversion of the carbohydrates to alcohol, maximum growth at
temperature of at least 90 F (32 C), and general hardiness to extreme
environmental changes in pH, temperature, and osmotic pressure.
The subject of ethyl alcohol production by fermentation has sti-
mulated renewed interest on account of attempts to find substitute for
gasoline. According to Lighty (1938), blends of alcohol may be used
satisfactorily in the present combustion type of motor. Present day de-
mands for fuel are great but the sources of petroleum are limited.
Inasmuch as there had been no study on the fermentative ability of
our local yeast in comparison with imported strains, this study was con-
ducted from July 1966 to April 1967, in the Department of Plant Patho-
logy, College of Agriculture, University of the Philippines, College, La-
guna.

MATERIALS AND METHODS

Pure cultures of three different yeast isolates from tuba, cham-
pagne, and magne were used in the experiment. Growth characteristics
of the three yeast isolates were studied on various standard agar media,
viz., PDA, malt agar, malt extract agar, yeast extract agar, and malt
yeast agar. The medium that best supported growth was used through-
out the experiment.
The percentage fermentable sugar of the molasses was analyzed.
Preparation of the starter. The medium was composed of molasses
and ammonium sulfate at the rate of 1 gm per liter of diluted molasses
and autoclaved at 15 psi for 15 minutes. One 250-ml flask containing
45 ml of the prepared medium was used for each pure culture of yeast
and incubated for 24 to 48 hr at 25 to 30 C.
Fermentation. A greater volume of the wort was prepared similar
to that of the starter but not sterilized. The pH was adjusted to 4.0
by the addition of concentrated HC1. The wort was seeded with uniform
amount of starter and incubated at room temperature.
In the distillation process, 3 uniform sets of distilling apparatus
were used. The fermenting bottles were divided into 3 lots, each lot
consisted of 3 bottles representing each yeast. All 3 bottles were dis-
tilled at the same time.
The percentage ethyl alcohol based on total fermentable sugars was













mpagne.
After completing all the trials, samples of distillates from each
Itment were mixed thoroughly to get a uniform solution. An aliquot
880 ml was taken from the solution, placed in a clean bottle, labelled
perly and analyzed in the Analytical Laboratory of the Department
Agricultural Chemistry.
The percentage of ethyl alcohol by volume was analyzed by means
specific gravity pycnometer while that of acetaldehyde was by means
the official method adopted from AOAC (Association of Official
culturall Chemistry).

RESULTS AND DISCUSSION

Morphological Characteristics

Form and size of cells. Cells of all the yeast isolates were larger
oval when young. In older cultures, the cells of tuba and champagne
sts appeared smaller and more or less round while magne yeast re-
ned oval but also smaller.
The average size of 200 cells each of magne, tuba, and champagne
It taken from a 48-hr old agar slant culture were 8.4 x 5.5 u, 8.2
4 u, and 8.1 x 5.2 u, respectively.
Agar colonies. The colonies of the three yeast isolates on PDA
e all white while in the other agar media, all were creamy white.
,a yeast exhibited profuse growth on PDA, yeast extract agar and
t yeast agar. Gas production was exhibited by magne yeast on PDA
malt yeast agar and by champagne yeast on PDA.

Fermentation of the Worts

The percentage of fermentable sugars from the molasses used was
7%. This was obtained by using the following equations:
% sucrose as invert + % reducing sugars = % fermentable sugars
38.90% + 14.80% = 53.70%
The percentage sucrose as invert and the percentage reducing sugars
e obtained by means of the Lane-Eynon General Volumetric Method














wmuwf&Wabva fbIc yffvOt.

Yeast Percentage Molasses
10 20 30

Champagne 68 92 128
Tuba 60 84 108
Magne 48 72 96



Table 1 shows the average number of hours of fermentation in
lation to different percentage of molasses and yeast isolates used.
overall results showed that the action of magne yeast was significal
faster than tuba which was also significantly faster than champagne

The minimum period of distillation was 15 min while the maxir
was 30 min depending upon the concentration of molasses used.
duration of distillation varied directly with the concentration of molas
At all concentrations, magne ranked first in the amount of distill
obtained, followed by tuba, and lastly by champagne (Table 2).
differences in mean yields produced by three yeast isolates and the m
differences at different levels of molasses are highly significant. TI

TABLE 2. Volume of distillates in ml/500 ml fermented molasses in relation
percentage molasses and yeast

Magne Tuba Champagne
Percentage Mt
1 2 3 1 2 3 1 2 3

10 22.5 16.0 21.0 20.0 20.0 15.0 11.5 11.5 9.0
20 40.5 38.0 48.5 21.5 26.5 30.0 22.0 19.5 21.0
30 89.5 89.3 78.5 84.5 85.0 77.5 35.0 36.0 30.0
MEAN 49.3 42.3 21.8

HSD: 0.05 0.01

Yeast ----- -4.75 ----- 6.18
Molasses - - 4.75 - - 6.18










AT.r'FTICT. WVR_ HKRTA ATTflP


e also a highly significant interaction between yeast isolates and per-
ntage molasses. This means that the behavior of yeast is not the same
different percentage of molasses.

Analysis of the distillates showed that magne yeast was able to
oduce 49.5% ethyl alcohol from molasses, while tuba and champagne
oduced 46.3% and 43.77%, respectively. With 53.7% fermentable
gars, magne gave 91.17% conversion of sugars to alcohol; tuba, 86.21%
.d champagne, 81.5%. Alcohol and carbon dioxide do not entirely
count for the carbon utilized during the dissimilation of simple sugars
cause other metabolic products such as acetaldehyde are also produced.
stillate from magne, tuba, and champagne yeasts contained 9.65, 21.75,
d 8.50 mg of acetaldehyde for every 100 ml distillate.

The presence of acetaldehyde indicated the presence of glycerol, an-
her metabolic product of fermentation. Normally, this polyhydroxy
cohol is formed to the extent of 3%, but Cooke (1958) reported that
Varying the experimental conditions, the yield of glycerol can be
nsiderably increased.

Although tuba ranked second to magne yeast in alcohol yield, it
owed a good ability in acetaldehyde production which made it a promis-
g commercial yeast for the production of glycerol.






LITERATURE CITED

OK, ARTHUR H. 1958. The chemistry and biology of yeasts. Academic Press,
New York. 763 p.
LDRETH, A. C. and G. B. BROWN. 1942. Modification of Lane-Eynon
method for sugar determination. J. Assoc. of Agr. Chem. 25: 775-778.
GHTY, L. C. and C. W. PHELPS. 1938. Gasoline-alcohol blends in internal
combustion engines, Ind. Eng. Chem. 20: 222.
IESCOTT, S. C. and C. G. DUNN. 1959. Industrial microbiology. McGraw-
Hill Book Co., Inc., New York. 945 p.














CHLOROTIC RING SPOT AND VEIN NECROSIS OF RAMBUTAN

A. N. PORDESIMO
UPCA Department of Plant Pathology, College, Laguna



On 28 September 1967, two unreported diseases of Nephelium lap-
paceum L. locally known as Rambutan was found to occur in Victoria,
Oriental Mindoro where this fruit tree is cultivated at a commercial
scale. The symptoms were typical of and very distinctly similar to
those incited by plant pathogens. In my observation, these diseases have
been recurring in this area for quite a long time but the damage they
cause may be negligible to alarm farmers.

Chlorotic Ring Spot

This disease was noted on seedlings and bearing trees. Affected
seedlings were chlorotic and appeared malnourished. The diagnostic
character is the presence of circular spots which are more discernible
on older leaves. Two types of spots were observed: one was distinctly
circular with concentric rings while the other was irregularly shaped
with indistinct rings (Fig. 1). I attribute this disease to a virus as the
primary causal agent and I consider this symptom to constitute one of
the symptom complexes of an even more destructive viral disease. Al-
though my test for seed transmission of the virus yielded negative re-
sult, I do not rule out the possibility of this means of transmission be-
cause a ring spot attributed to a virus has already been experimentally
demonstrated on coffee to be seed transmitted (Reyes, 1961; Valdez,
1966).
According to Nursery Farm Supervisor Antonio Zamora of APC
Merit Demonstration Station at Victoria, Oriental Mindoro, susceptible
trees were selections designated as Magsaysay, Victoria, Infantado, Que-
zon, Fortich, Princess Caroline, Sto. Tomas, and Ferrera's Ponderosa;
resistant or possibly symptomless were Zamora, Baby Christie, Baby
Eulie, Roxas, Laurel, Sr., and Osmefia. All these selections came from
one mother tree named Queen Zaida planted in 1939 and now showing
distinct ring spots on its water sprouts.

60


ohn l^04;#--










Wougrv WUmmEmm


FIc. 1. Chlorotic ring spots of Rambutan photographed using trans-
mitted light. At left are indistinct chlorotic areas; at right are
distinct circular areas surrounded with concentric rings. (Photo-
graphed by the UPCA Photographic Division)











PHYTOPATHOLOGICAL NOTE


Vein Necrosis

This leaf disease can defoliate seedlings as well as bearing trees.
On the leaf blade, lesions are at first hydrotic and dark-colored on the
nether surface. Soon they turn brown and dry and are surrounded by
a yellowish border; when veins are infected, they turn brown and an
oak-leaf pattern of necrosis results (Fig. 2).
Slide mounts obtained from lesions and stained with congo red con-
sistently yielded bacterial cells that were rod-shaped. Yellowish colonies
invariably developed on beef-extract-peptone agar plates on which was
streaked dilute suspension obtained from macerated young lesions. Trans-
fers to PDA slants developed profuse growth. Preliminary inoculations
demonstrated that the isolates tested were pathogenic to Rambutan seed-
lings. On these bases, I consider the primary causal agent to be a bac-
terium, a species of Xanthomonas.
This disease was also noted on a seedling of variety Maharlika at
the UPCA in December 1967. It is not confined to Oriental Mindoro.
An etiological study to determine the identity of the causal bac-
terium is underway.

Recommendations

It is advisable to restrain movement of chlorotic-ring-spotted nur-
sery stocks from Oriental Mindoro. It is suspected that ring-spotting
may only be one of the symptom complexes of an even more destructive
disease of this fruit tree.
When vein necrosis becomes a problem in the nursery, protective
sprays with Bordeaux mixture 4-4-50 must be applied periodically.






LITERATURE CITED

REYES, T. T. 1961. Seed transmission of Coffee ring spot by Excelsa coffee
(Coffee excelsa). Plant Dis. Reptr. 45: 185.
VALDEZ, R. B. 1966. The current status of the ring spot disease of coffee in
the Philippines. Philippine Agriculturist 50: 267-275.













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PHYTOPATHOLOGY


Republic of the Philippines
Department of Public Works and Communications
BUREAU OF POSTS
Manila


SWORN STATEMENT
(Required by Act 2580)


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


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

Business Manager: Romulo F. P. Quemado .....

Owner: Philippine Phytopathology ..............
Publisher: Philippine Phytopathology ............
Printer: Araneta U Printing Press ..............


ADDRESS
College of Agriculture
U.P., College, Laguna
Union Carbide, Philippines
Incorporated
P.O. Box 677, Manila
College, Laguna
College, Laguna
Victoneta Park, Rizal


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


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

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


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


MARIANO R. PEFIANCO
Notary Public
Until December 31, 1967


NOTE: This form is exempt from the payment of documentary stamp tax.













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