Front Cover
 Table of Contents
 Front Matter
 Reliable and economical inoculum...
 Rhizoctonia disease of salgo (Wikstroemia...
 Spatial dynamics of banana diseases...
 Economic losses is Abaca due to...
 Geographic distribution of ratoon...
 Note: Light microscopy study on...
 Abstracts of paper presented a...
 Back Matter
 Back Cover

Group Title: Journal of Tropical Plant Pathology
Title: Journal of tropical plant pathology
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00090520/00045
 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-December 2002
Frequency: semiannual
Subject: Plant diseases -- Periodicals -- Philippines   ( lcsh )
Plants, Protection of -- Periodicals -- Philippines   ( lcsh )
Genre: periodical   ( marcgt )
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: VID00045
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 54382605
issn - 0115-0804

Table of Contents
    Front Cover
        Front Cover 1
        Front Cover 2
    Table of Contents
        Table of Contents
    Front Matter
        Front Matter
    Reliable and economical inoculum production method and disease resistance evaluation techniques to stenocarpella macrospora in maize
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
    Rhizoctonia disease of salgo (Wikstroemia lanceolata L.) in the Philippines and its control
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
    Spatial dynamics of banana diseases in monocropping and multicropping system
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
    Economic losses is Abaca due to bunchy-top and mosiac virus diseases in the Bicol and Eastern Visayas regions
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
        Page 36
    Geographic distribution of ratoon stunting disease of sugarcane in the Philippines
        Page 37
        Page 38
        Page 39
        Page 40
        Page 41
        Page 42
        Page 43
        Page 44
        Page 45
        Page 46
        Page 47
        Page 48
    Note: Light microscopy study on the pathological histology of colletotrichum gloeosporioides (Penzig) Penzig & Sacc. in onion
        Page 49
        Page 50
        Page 51
        Page 52
        Page 53
    Abstracts of paper presented a during the 33rd pest management council of the Philippines, Inc. Annual scientific metting held at Grand Men Seng Hotel, Davao City on May 8-10, 2002
        Page 54
        Page 55
        Page 56
        Page 57
        Page 58
        Page 59
        Page 60
        Page 61
        Page 62
        Page 63
    Back Matter
        Page 64
    Back Cover
        Page 65
        Page 66
Full Text


Formerly Philippin

January De

The Philippine Phytop
c/o Department c
I IP I nq RafnR



IMBER 1 & 2
:mber 2002

d by
logical Society, Inc.
plantt Pathology
illenp Laauna I A,

ippine Phytopathological Society, Inc.

Published by The Pt




VOLUME 38 NUMBER 1 & 2 January to December 2002


Reliable and Economical Inoculum Production Method
and Disease Resistance Evaluation Techniques to
Stenocarpella macrospora in Maize
C.B. Pascual, P.S. Guzman and A.M Salazar 1-8

Rhizoctonia Disease of Salago (Wikstroemia lanceolata L.)
in the Philippines and its Control
N.G. Tangonan and V.M. Escopalao 9-15

Spatial Dynamics of Banana Diseases in Monocropping
and Multicropping System
K.M. K. Umadhay and A.D. Raymundo 16-30

Economic Losses in Abaca Due to Bunchy-top and Mosaic
Virus Diseases in the Bicol and Eastern Visayas Regions
A.D. Raymundo, B.P. Cipriano, S.I. Garcia, R.T. Borromeo
and P.B. Tapalla 31-34

Geographic Distribution of Ratoon Stunting Disease
of Sugarcane in the Philippines
F.M. Dela Cueva, M. P. Natural, R.G. Bayot, E.M. T.Mendoza
and L.L. Ilag 35-46

Note: Light Microscopy Study on the Pathological Histology of
Colletotrichum gloeosporioides (Penzig) Penzig & Sacc.
in Onion
R. T. Alberto, A. V. Tiedeman, G. Wolf and H.L. Danzinger 47-51

Abstracts of Papers Presented during the 33rd Pest Management
Council of the Philippines, Inc. Annual Scientific Meeting held
at Grand Men Seng Hotel, Davao City on May 8-10, 2002 52-61

t^M 'P(l/o



orted by the Institute of Plant Breedi
irtment of Agriculture-Bureau of Agrici

ersity Research and 3Associate Profe
te Professor, Department of Agronor
ros, College, Laguna 4031, PI

The availability of reliable score
resistance breeding program. Curn
iaize resistance to disease complex
ie effective inoculum production
methods for these diseases. At IP
nd inexpensive methods of inocu
'chnique against S. macrospora.
lost efficient and reproducible met
ie use of corn husk substrate. Th
loculated and the optimum time fol



ge of Agriculture, UP Los Bafos anc

pectively, Institute of Plant Breedir
ge of Agriculture, University of the F
('Corresponding author e-mail

method is the cornerstone of any
ie constraints in the evaluation of
i by Stenocarpella macrospora are
AI and the large-scale screening
authors developed simple, reliable
auction and resistance evaluation
:he techniques that were tried, the
large-scale disease screening was
um dose, the part of the ear to be
tinn warp dAtprminAd Innrmlatinn

INTRODUCTION condition, then ear rot and stalk rot which o
after flowering stage. Natural ear rot infect
ie incidence of Diplodia disease on corn usually starts on the outer husk near the bas
hpan ~larminn in rirant \uare in the the =Qr rlin-mnt+ +r% +th c+ll, C mnn

Pascual, Guzman and Sal;

I to control the disease, many farm
o other crops like sugarcane in sol

resistance is still considered the mi
cal and effective control against
(Olatinwo et al, 1994). The availability
screening method is the cornerstone
stance breeding program. Currently, 1
its in the evaluation of resistance
Caused by S. macrospora in both put
ns and private seed companies in 1
es are the effective inoculum product
and large-scale screening methods.

study was conducted to develop
and inexpensive inoculum product
e as well as effective methods
ating between resistance a
ble corn genotypes for diseases cause
acrospora. The reproducibility of the
es for identifying resistant gene
5 and its feasibility for large-sc
g were also determined.

iiin. -|r| | .. . ,, - -- IJ% LVV %.. I I II 1- A ii i I II I 1 WV- .
treatments, applied at the center rows,
Comparison of MedialSubstrate for evaluated in CRD with three replications.
Inoculum Production length of time used for inoculating 15 plar

cuDatea at z-ju-u; unaer contini
editionss until pycnidia formation
aximum of two months if pycnidia
rmed. Pycnidia were scraped frorr
ibstrate surface with 20 ml distilled
isk/plate. Spore concentration prod
ich treatment was determine
aemacytometer. The experiment was
sing five plates or flasks per treat
>mpletely randomized design (CRD)

Effect of Inoculum Concentrati
Differential Reaction

The sweet corn susceptible variety
as planted in the IPB screenhouse ii
ots with a spacing of 20 cm between t
n between rows. The treatments wen
concentration (2x103, 1X104, 2x104, 3x11
:104 spores per ml). Water without s
sed as control. One ml spore susl
ich concentration was placed at the w
iy-old plants for reaction to leaf bli
ime spore concentration was used tc
ric nf th rnrn iare at ) AIk nft r cilkin

*1_ 1-J.--A :-U -1_^--_- --1.:__-1.-- :

,nt were: 1) injection ot one ml sport
I (1x104 spores/ml) to the butt end <
(Alovera, 2001), 2) by inserting fung
covered toothpick through the sheal
iway between the butt and the tip i
and 3) by inserting about 3 pieces I
husk substrate containing pycnid
prepared as described above, through
reaching near the butt end of the ea
inoculum was prepared using
in of the toothpick method describe
ers (1988) on D. maydis ear and sta
is. The toothpick were placed
rered with autoclaved sorghum seed
with pure culture of the fungus ar
for 3 to 4 wk. All inoculations wei
wk after silking, the most susceptib
e plant.

inoculation methods were done fi
development during the silking stage:
)f spore suspension at the secor
n the base of the plant, 2) toothpick
which fungus-covered toothpick wE
between the stalk and the leaf sheal


raw r:

'e the ground. and corn husk substrate (Table 1, Fig. 1).
pycnidia in OMA were submerged in the
treatment without the pathogen served as although some were formed as si
rol in all the inoculation methods. High aggregates. Most pycnidia were submer(
ive humidity was maintained by daily misting V8 juice agar. The pycnidia formed in PDi
e plants. Disease assessment was done at very few, small and all were submerged w
dough stage for leaf blight and stalk rot and pycniospores recovered. Spores extracted
irvest for ear rot. media/substrate were highest in corn
followed by OMA and the least in V8 juice a
Evaluation of Resistance for
Leaf Blight and Ear Rot Effect of Inoculum Concentratior
on Differential Reaction
>ixty yellow corn inbreds, yellow and white
ids were screened for resistance to leaf Leaf blight, ear rot and stalk rot
t and ear rot using the best developed observed in all levels of inoculum concentr
unique described previously. The seeds of (Table 2). There were no significant differe
i_..- -:. -i - :_ -- Ii LI - _1 . . _x .l _ir-

ktI*^f ^9' *cEc tfl t% I An E.4iIIin

" i", ^f nif-f ... I... ..sl- i^"

I lU-r LUI I IILUtI VV W oulcoi UI
ting resistant and susceptit
Sto S. macrospora. Reaction of entri
n resistant to highly susceptible for le
,ening (Table 4). Two and eight entri
!d as resistant ad highly susceptib
ly. More entries were classify
oderately resistant and susceptit
In ear rot resistance evaluatic
among entries was narrower rangil
erately resistant to highly susceptib
. . - i,. -.... . ..-.- . J - ,1- j l

ariment was repeated suggesting be obtained in the screening of thousands
oducibility of the inoculation techniques. using corn husk as substrate.

DISCUSSION Our study is the first rennrt on the iI

too low to detect genotypic da
reening methods, which simulate
fraction of host and pathogen is an
isideration in our breeding program.
colonized substrate like toothpick
lulate natural infection since the
Jrce is mycelium, not spores. Pyc
)uld be used as inoculum in
rmplasm for resistance to Stel
scies (Morant et al. 1993). Use of py
pension more closely simulate
action and it was previously suggest
ild be sprayed or injected.
siccation of spores is a problem with
ich could results to low levels of infec
al. 1996) or none at all as shown in 1
-ction requires large amount of pyc
large-scale screening and only fe
Ild be injected per unit time.

Synthetic media can be used
iduction (Morant et al. 1993) but the c
ts, vitamins and carbohydrates
)ensive. The culture media like OM
:e agar can also produce pycnidia bt
m were submeraed in the aaar mak

II~_ rrrr I Ir

..... ..

.r i.v u.iv W. v. 1..u ..- ui v..U nunu.I.... ,Jui I IVI-RJrMI'" I IVIM, VVMrrl' Fr-l L, VMIN 1' UMLCIN t O .
,pril 2001 to the Intellectual Property Rights 1993. A synthetic medium for mass
officee at UPLB. production of pycniospores of Stenocarpella
sp. Plant Disease 77:424-426.
The authors have successfully and
repeatedly used corn husk technique in NUTTER FW Jr., JENCO JH. 1992. Development
differentiating resistant from susceptible of critical-point model yield loss models to
lenotypes. The technique was effective, simple, estimate yield losses in corn caused by
ery cheap and applicable for large-scale Cercospora zea-maydis. Phytopathology
screening of Stenocarpella leaf blight, ear rot and 82:994 (Abstr.)
talk rot resistance in corn.
LITERATURE CITED Inheritance of resistance to Stenocarpella
macrospora (Earle) Sutton, ear tot of maize
LOVERA RB. 2001. Effect of environmental in mid-altitude zone of Nigeria. European J.
factors on Stenocarpella macrospora (Earle) Pit. Pathol. 105(6):535-543.
Sutton and disease-yield loss relationship as
affected by site inoculation and inoculum REID LM, HAMILTON RI, MATHER DE. 1996.
concentration in corn (Zea mays L.). PhD Screening maize for Gibberella ear rot. Tech.
Dissertation, College, Laguna, Philippines, Bull., Eastern Cereal and Oilseed Res. Centre.
UPLB. 122p. Canada, pp40.

;HAMBERS KR. 1988. Effects of time of SALAZAR, AM. 2001. Ear rot The bane of corn
inoculation on Diplodia stalk and ear rot of production in Region 10. Corn RDE News
maize in South Africa. Maize Abstracts Update Vol. 2(1), 8p.
STEVENS FL, CELINO MS. 1931. Two diseases
;UTTLER HG, CRUMLEY FG, COX RH, COLE caused by Diplodia. Phil. Agric. 20:370-374.
AE. 1980a. Diplodiol: A new toxin from SUTTON BC, WATERSTON JW. 1966. Diplodia
Diplodia macrospora. J. Agric. Food Chem. macrospora. In: CMI Description of
28:135-138. pathogenic Fungi and Bacteria No. 85.
Commonwealth Agricultural Bureau, Kew,

1980b. Chaetoglobosin K: A new plant
inhibitor and toxin from Diplodia macrospora.
J. Agric. Food Chem. 28:139-142.

)ALMACIO SC, LOZANO GP. 1987. Note: Leaf
blight, ear rot and stalk rot of corn caused by
Diplodia macrospora Earle in the Philippines.
Phil. Phytopathol. 23:22-23.

DDINS AH. 1930.. Dry rot of corn caused by
Diplodia macrospora. Phytopathology

The authors are indebted and thankful for the
Schnical assistance of Ms. Amalia Ilagan, Mr.
Zeynaldo Alegre, Ms. Mercedes Dreje, Ms. Tonette
.aude and Mr. Reynaldo Bagui; and to Mrs. Cherry
Elevate for her assistance during the preparation
if manuscript.

,117mnn =nd A2127n

Table 1. Pycnidia formation and sporulation of Si
on different culture media and substrat

Medium/Substrate Pycnidia Onse
Formation1 Pynidia F

Potato dextrose agar + 6

Oatmeal agar +++ 3

V8 juice agar +++ 3

Corn leaves decoction agar none
Corn leaf substrate none
Corn stalk substrate none
Corn grain substrate none
Corn husk substrate +++ 3

Toothpick substrate none

SFormation of pycnidia was based on visual observation noted by +
2 WAI weeks after inoculation
3In a column, means followed by the same letter are not significantly

Table 2. Severity of leaf blight, ear rot and stalk
different spore concentrations of Steno,

Spore Concentration
(pycniospores/ml) Leaf blight (% infection)1

2 x 103 50-65a

1 x 104 60-75a

2 x 104 50-75a

3 x 104 60-80a

4 x 104 50-80a

5 x 104 60-80a

Control (without spore) Ob

Means In a column having similar letter are not significantly differer
'% infection of upper leaf canopy with lesion length ranging from !

ocarpella macrospora isolate grown

f Sporulation
nation (pycniospores x Remark

0.000a all pycnidia
submerged in agar
0.054c some pycnidia
submerged in agar
0.023b most pycnidia
submerged in agar
0.084d pynidia formed on
husked surface

i: + = few pycnidia, +++ = abundant pycnidia.
ferent using LSD(oos)

in sweetcorn variety, Asukar, as affected by
oella macrospora

Disease Severity
Srot (% ear infection) Stalk rot (% incidence)

50-80a 70 3a

60-100a 82.6a

75-100a 88.8a

75-100a 92.4a

75-100a 86.3a

75-100a 86.0a

Ob Ob

ing LSD(oo5)
10 cm.

Reliable and economical inoculum

Table 3. Rate of inoculation and inoculation of ASL
Stenocarpella macrospora using differed

Disease Inoculation Method % Infection o
leaf canopy or

Leaf blight a) spore suspension 61.
dropped on the whorl

Pascual, Guzman and Salazar

Figure 1. Colony characteristics of Stenocarpella macrospora on oatmeal agar and corn husk
substrate 4 weeks after incubation at 250C under continuous artificial light. Note the
presence of black pycnidia (with arrow) aggregating into large clumps on the
surface of the oatmeal agar and corn husk.



1Awarded the National Research Symposium, Agriculture and Fisheries Modernization Act (AFMA) I
& D Paper, Department of Agriculture-Bureau of Agricultural Research's 14th Anniversary and Recognitio
Day, October 4, 2001, BSWM Conference Hall, Quezon City, Philippines. Funded by the USM-base
Philippine Industrial Crops Research Institute (PICRI).

2University Professor/Laboratory In-Charge and Science Research Assistant, respectively, Plar
Pathology Research Laboratory, Crop Research Division, University of Southern Mindanao Agriculture
Research Center (USMARC), University of Southern Mindanao, Kabacan, Cotabato 9407 Philippines.

Rhizoctonia disease of Wikstroemia lanceolata L. (locally known as salago)
caused by Rhizoctonia solani Kuhn is heretofore reported for the first time in the
Philippines. The pathogen infects all stages of the plant. It causes damping-off of
seedlings, leaf blight, and twig blight. In seedlings, symptom is characterized by
girdling, discoloration of vascular tissues, rotting on the base, and toppling over.
In mature plants, symptom is characterized by blighting and drying up of the
leaves. Affected twigs dry up, leaves fall-off and die back. Whitish mycelia and
abundant sclerotia are observed on infected twigs and leaves. In culture, the
pathogen produces brown to dark brown sclerotia of varying sizes (1 to 4 mm) in 5
to 7 days; the characteristic right angle mycelium, measures 34.15 x 14.32 um.
Inoculated healthy seedlings develop the characteristic symptom, 5 to 7 days after

Five fungicides applied as protectant and eradicant were found effective
benomyll, difenoconazole, mancozeb, metalaxyl and tridemorph). Likewise, six
biological control agents (BCA) namely Trichoderma sp. T. harzianum, T.

effects against R. solani in vitro. The f
i.e. 69.85 to 89.92% and showed their
suppressing further the growth of R. soi

Key words: Wikstroemia lanceolata, Rhizoctol
T. viride, Penicillium sp., Rhizopus sp., biological;


Wikstroemia lanceolata L. is gaining
popularity as a potential fiber crop. It is regarded
as one of the excellent materials in' the
manufacture of money, bank notes, stencils,
strong ropes, art and grade papers,
documentary papers and others. This fiber plant'
is now commercially grown in Cebu, Bohol,
Misamis Oriental and Leyte, Philippines.

*st five BCA had high degrees of control,
nycoparasitic or antagonistic activity by
ini under screenhouse conditions.

a solani, Trichoderma harzianum, T. pseudokoningii
nd chemical control

There are six fungal pathogens reported to
cause diseases of W lanceolata in the Philippines
(Tangonan, 1999). Stem rot caused by
Botryodiplodia theobromae Pat., leaf spot by
Colletotrichum sp., pink disease by' Corticium
salmonicolor, and root rot by Fusarium sp. and
Pythium sp. were reported. Diseases attacking W
lanceolata greatly affect fiber quality and yield
potential if not diagnosed and treated early.

__ ___ _ ____

Rhizoctonia disease of W lanceolata was
first noted by the authors in 1999 at PICRI
experimental area where W lanceolata is grown.
The authors also noted disease incidence at the
Fiber Industry Development Authority in
Manambulan, Toril, Davao City in 1999. Disease
infections appear serious during favorable
conditions for disease development. If not
treated/managed properly it may lead to great
loss in the fiber industry.

This study aims to determine the etiology of
the disease characterized by damping-off of
seedlings, leaf blight and twig blight; to
characterize the disease based on symptoms
including the morphological and cultural
characteristics of the pathogen; and to evaluate
effective fungicides and potential biological
control agents against the pathogen.


Isolation of the Causal Fungus

Infected plant parts were collected from
PICRI, USM and Manambulan, Toril, Davao City
where W lanceolata are grown. Specimens
were placed in polyethylene bags and brought in
the laboratory for direct microscopic observation
and isolation of suspected pathogen using issue
planting technique. Specimens were washed in
running water to remove surface dirt, tissues
were cut (2 to 3 mm), disinfected with 10%
NaHCI for 2 min, rinsed with 3 changes of sterile
distilled water and planted onto potato sucrose
agar (PSA). Series of transfers were done until a
pure culture was obtained.

Pathogenicity Test

Two-week-old pure culture of the fungus was
noculated to healthy W lanceolata seedlings
sing swabbing and drenching method.
noculated seedlings were covered with
polyethylene bags for 24 hr to maintain the
lumid condition necessary for disease
development. Re-isolation was done to confirm
ts identity.

Identification of the Causal Fungus

The fungal pathogen was identified through

lanceolata, direct microscopic examination and
through its morphological and cultural
characteristics in PSA. The sclerotial bodies and
hypha were measured.

In Vitro Test of Fungicides and Biological
Control Agents

Seventeen fungicides using manufacturers'
recommended rates were tested against R. solani
in vitro. Agar disc technique was used.
Treatments were replicated four times. Plates
were incubated at 28-300C 72 hr after incubation.

Eight fungal antagonists, namely; Aspergillus
sp. Paecilomyces lilacinus, Penicillium sp.,
Rhizopus sp., Trichoderma sp., T. harzianum, T.
pseudokoningii and T. viride were tested for their
antagonistic effects against R. solani using dual
culture method. With a cork borer, a 5 mm
mycelial disc of each of above BCA were obtained
and planted on the surface of plated PSA with
each of the corresponding BCA and R. solani
positioned 60 mm diametrically opposite each
other. Control set-up consisted of the pathogen
alone. For chemical check, one ml of benomyl
solution (1.25 ml/I) was added and mixed
thoroughly with agar and allowed to congeal, then
the pathogen was planted at the center.
Treatments were replicated four times. Plates
were incubated at 28-300C.

In Vivo Test of Fungicides

Effective fungicides in vitro were further tested
for their efficacy under screenhouse condition.
Eight fungicides at recommended rate (g/l water),
namely: benomyl, 2.19; captain, 3.75;
chlorothalonil, 4.54; difenoconazole, 5.63; maneb,
3.75; mancozeb, 2.81; metalaxyl, 6.88; and
tridemorph, 2,81, were applied as protectant and
eradicant. A randomized complete block design
with all treatments replicated three times was
used. As protectant, fungicides were applied one
day before pathogen inoculation. As eradicant,
fungicides were applied one week after pathogen
inoculation when symptom were already visible.
Fungicides were applied by spraying at one week
interval for one month.

Data Gathered

Rhizoctonia disease of salago

determined by measuring the zone of growth of
the pathogen using the following arbitrary rating

Zone of growth (mm)
31 and above

Very effective
Not effective

Using Biological Control Agents. The
interaction between fungal pathogen and BCA
was studied following the rating scale used by
Bell et al (1982) as follows:

Class 1 = BCA completely overgrew the
pathogen and covered the entire medium

Class 2 = BCA overgrew the pathogen at least
two-thirds of the medium surface

Class 3 = BCA and pathogen each colonized
one-half of the medium surface and neither
organism appeared to dominate the other

Class 4 = Pathogen overgrew BCA at least two-
thirds of the medium and appeared to withstand
invasion by the BCA

Class 5 = Pathogen completely overgrew BCA
and occupied the entire medium surface

An isolate of BCA was considered antagonistic
to R. solani if the mean score of a given
comparison (when rounded to nearest whole
class number) was less or equal but not highly
antagonistic if the number was greater than or
equal to 3.

Screenhouse Test. Disease severity was
determined using the formula:

Disease Index (DI) = Ono + in1+ ...4n4 x 100
Ono.. 4n4 = refer to the number of plants
showing the rating of 0,1,2,3, and 4, respectively.
4 = represents the highest rating scale
5 = total number of plants

Percentage degree of control was computed
using the following formula:

% Degree of Control = DI untreated DI treated x 100
DI untreated



R. solani infects all stages of W. lanceolata at
PICRI, USM. It causes damping-off of seedlings,
leaf blight and twig blight on older plants. It is soil-
borne pathogen and infects the host during
favorable conditions.

Initial symptom of damping-off of W
lanceolata is the yellowing of leaves, girdling of
the affected region, discoloration of the vascular
tissues, rotting on the base, wilting and finally
toppling over of the seedlings (Fig. 1). In mature
plants, water-soaked discoloration followed by
blighting and drying up of leaves were noted (Fig.
2). Affected twigs dried-up, leaves fall-off, and the
plants exhibit dieback. Whitish to brownish
mycelial threads and brownish to dark brown
sclerotial bodies with varying sizes were apparent
on the affected twigs and leaves.

Morphological and Cultural Characteristics

In PSA, the fungus produced creamy white
mycelia and brown to dark brown sclerotial bodies
of varying sizes (1 to 4 mm) in 5 to 7 days (Fig. 3).
The characteristic right-angle branching of the
hyphae measured 34.15 x 14.32 um (Fig. 4). The
fungus was identified as Rhizoctonia solani Kuhn.

Pathogenicity Test

The inoculated seedlings exhibited the
characteristic symptom described above in 5 to 7
days after inoculation. The same pathogen was
re-isolated exhibiting similar morphological and
cultural characteristics.

Efficacy of Fungicides In Vitro

Bioassay of 17 fungicides was conducted to
determine their effects on the growth of R. solani.
The zone of growth of the pathogen was
significantly affected by the fungicides used (Table

Tangonan and Escopalao

1). Of the test fungicides, however, only eight
were found effective in inhibiting the growth of R.
solani. Tridemorph, chlorothalonil (Daconil),
metalaxyl, difenoconazole, benomyl, captain,
maneb and mancozeb were found very effective
in inhibiting the growth of R. solani with the
comparable means ranging from 0.00 to 14.50
mm zone of growth. Efficacy of these fungicides
were further tested in vivo. The rest of the
treatments that had higher zones of growth were
considered not effective because the pathogen
was able to survive and grow.

Results imply that the lower the zone of
growth of the pathogen, the more effective the
corresponding fungicides was, and the higher the
zone of growth of the pathogen, the less effective
it is.

Dual Cultures of Biological Control
Agents and Rhizoctonia solani

The four species of Trichoderma, T.
harzianum, T. pseudokoningii and T. viride
completely overgrew the pathogen and covered
the entire medium surface after 7 days of
incubation. Hyphae of R. solani ceased to grow
upon contact with the hyphae of any of the
Trichoderma species. Rhizopus and Penicillium
with rating of Class 2, overgrew the mycelia of R.
solani at least two-thirds of the medium surface.
Aspergillus and Paecilomyces lilacinus with
rating of Class 4, overgrew the BCA at least two-
thirds of the medium surface (Fig. 5).

In Vivo Test of Fungicides

Eight fungicides screened for their efficacy'
significantly reduced disease severity compared
to control (Table 2). As protectant, the non-
inoculated control first exhibited disease
symptom, 5 to 7 days after inoculation. Plants
treated with chlorothalonil (Daconil) and maneb
exhibited symptom 16 days after inoculation,
while captain showed symptoms 18 days after
inoculation. Treatments with benomyl,
mancozeb, metalaxyl, difenoconazole and
tridemorph were very effective and exhibited no
disease. These fungicides totally suppressed
disease development with 100% degree of
control applied as protectant. However, captain,
chlorothalonil (Daconil) and Maneb 80 had mean
severity infections of 32.50, 34.17, 37.33 and

42.50%, respectively, with degree of control that
ranged from 45.97 to 48.67% significantly
different from the control (Fig. 6).

Meanwhile, the fungicides applied as
eradicant significantly lowered severity Infection
compared to non-treated control (Table 2).
Highest degree of control was obtained on plants
treated with benomyl with 83.78%, mancozeb
81.78%, metalaxyl 79.50%, difenoconazole
78.63% and tridemorph 78.53% with severity
infections of 10.50, 11.75, 13.22, 13.78 and
13.85%, respectively. However, those treated
with maneb, chlorothalonil and captain had
degrees of control that ranged from 42.64 to
44.26% and severity infections of 29.50, 34.00,
37.00 and 38.85%, respectively. The non-treated
control plants exhibited total blighting, defoliation
and ultimate death of the plants. Results revealed
that the fungicides used sufficiently controlled R.
solani in W lanceolata when applied as protectant
and eradicant. The high degree of control
indicated high degree of efficacy to the test

Moreover, five BCA, namely: Trichoderma sp.,
T. harzianum., T. pseudokoningii, T. viride and
Penicillium sp. were found effective in controlling
R. solani under screenhouse conditions (Table 3).
No parasitism was observed on plants applied
with Rhizopus, Penicillium, Aspergillus and P.
lilacinus. The degree of control on plants treated
with Trichoderma sp. was 85.25%, T. harzianum..
89.92%, T. pseudokoningii, 86.78%, T. viride
86.60%, Penicillium 69.85% and the chemical
check benomyll) had 85.48% white the non-
treated Control had 0%. The antagonists showed
their mycoparasitic activity by suppressing further
the growth of R. solani.


vitro antagonism of Trichoderma species
against six fungal pathogens. Phytopathology

TANGONAN NG. 1999. Host Index of Plant
Diseases in the Philippines, 3rd Edition.
Department of Agriculture Philippine Rice
Research Institute, Munoz, Nueva Ecija,
University of Southern Mindanao, Kabacan,
Cotabato, Philippines, 408 p.

Rhizoctonia disease of salago

Table 1. Zone of growth of Rhizoctonia solani as affected by 13 fungicides after 72 hours

Treatment I II III IV Total Mean* DC

Fosetyl-AI (Aliette 80)
Triadimefon (Bayleton)
Benomyl (Benlate)
Tridemorph (CAlixin)
Captan (Captan 50)
Chlorothalonil (Daconil)


Methyl thiophanate (Fungitox OH)32.00
Copper hydroxide (Funguran) 32.00
Maneb (Maneb 80) 0.00
Metalaxyl Ridomil M2) 0.00
Difenoconazole (Score 200) 0.00
Mancozeb (Tranzeb) 18.00
Copper oxychloride (Vit. Blue) 42.50






*Means in a column having similar letter are not significantly different at 5% level, DMRT.
Legend: DC = Degree of Control
VE = Very Effective
NE = Not Effective

Table 2. Mean percentage (%) control of eight fungicides against Rhizoctonia solani, one month
after protectant and eradicant spray applications under screenhouse conditions


Control (non-treated)





Degree of Efficacy

Not Effective
Not Effective
Not Effective
Not Effective

Means in a column having similar letter are not significantly different at 5% level, DMRT.

Rhizoctonia disease ow iaiago

Table 3. Mean percentage (%) control of five bio]
one month after protectant and eradican

Treatment Protectant

Trichoderma harzianum 89.92a

richoderma pseudokoningii 86.78a
Tichoderma viride 86.60a
Trichoderma sp. 85.25a
Penicillium sp. 69.85a
Benomyl 85.48a
Control (non-treated) O.OOb

Means in a column having similar letter are not significantly i

Figure 1. Wikstroemia lanceolata affected with
Rhizoctonia solani, showing wilting
and girdling of the collar region.

gical control agents against Rhizoctonia solani
spray inoculations under screenhouse condions

Eradicant Degree of Efficacy

86.75a Effective

84.38a Effective
83.60a Effective
84.15a Effective
70.75a Effective
84.48a Effective
.00b Not Effective

ferent at 5% level, DMRT.

N,.. ,
*' ^ ^ -

W '. ...

Figure 2. Blighting and drying up of the
affected leaves of Wikstroemia
lanceolata under field condition.

...wjIaEil allu V icopalao

Journal of Tropical Plant Pathology 38:16-30



Portion of the MS Thesis of the senior author. Supported by the Philippine Council for
Advanced Science and Technology Research and Development (PCIERD) and Tagum
Agricultural Development Corporation, Panabo, Davao del Norte, Philippines

'Former graduate student and 2Professor, Department of Plant Pathology, University of the
Philippines Los Baios (UPLB), College, Laguna, Philippines (2Corresponding author; Email: {
HYPERLINK mailto:billyray@laguna.net },

The spatial development of Sigatoka, bunchy-top, Moko, and Fusarium
wilt diseases of banana was determined in monocropping and multicropping
systems using variogram analysis. Under the conditions of the experiment,
spatial development of bunchy-top and Moko differed between the two
cropping systems with bunchy-top spreading in greater distance in the
monocropping system and Moko in the multicropping system

Key words: Epidemiology, bunchy-top, Sigatoka, Moko, Fusarium wilt, disease spread,
cropping systems, variogram analysis


Diseases are major constraints in banana
production worldwide (Buddenhagen, 1968;
San Juan, 1977; Pedrosa, 1993). In extreme
cases, temporary or permanent collapsed of
local banana industries might happen as a
result of the effect of disease as in the case of
Sigatoka leaf spot (Meredith, 1970). In
Mindanao, Philippines, the cost of controlling
Black Sigatoka has increased annually as 23
to 30 cycles of aerial spray of fungicides per
year have become necessary (Roperos and
Magnaye, 1991).

Diseases have also become critical issues
in the export of banana. Presently, the
prospect of exporting Philippine banana to
Australia has been stymied by the suspected
presence of the bacterial wilt pathogen in the
fruit (Anonymous, 2002). Such suspicion has
been extended to the fungus causing banana

Although disease control strategies have
generally been successful in large-scale banana
plantations (Roperos and Atabug, 1985), crucial
aspects of the dynamics of major diseases that
might contribute to the economic feasibility of
these strategies are poorly understood under
Philippine conditions. Knowledge of this aspect,
the key input to disease control, is not known in
most of the diseases that are destructive locally.
Umadhay and Raymundo (1999) study the
temporal dynamics of major banana diseases in
monocropping and multicropping systems but
additional and more committed effort is clearly
needed. Currently, the cases involving bacterial
wilt and Fusarium wilt appear to be of paramount
importance. More specifically, knowledge of
spatial development of banana diseases, vital in
disease management, is sorely lacking.

This paper, a corollary to the earlier work of
Umadhay and Raymundo (1999) presents an
analysis of the manner of spread of bunchy-top,
Moko, and Fusarium wilt, three of the most
destructive local diseases of banana.


VWV cI IULdLtU IdallIII IIUIII LIti VallUy l11 yiddpiIl sUW U tlidL I
the third month of observation, new monocropping system, the probable dist
hat occurred next to the source inoculum dispersal was up to 13.68 m (Fi
ill patches. On the fourth and fifth

although proba

ntn (
le di

I 1luIIU lu I u p
icropping. TI

Jom. As observed in the experimental site may cause an aggregation pattern esp(
ie two cropping system, there were many the monocropping system was roc
,I innrlahmrn c nlirr-e nrnant In thA ,nnf!,,f f Alnl,, nlrntnrl hnnonn nnA


still clearly evident that intercropped ENGLUND E, SPARKS C. 1991. GEO.
affected the possibility of contact 1.2.1. Geostatistical Environm
roots of the banana plant. At this Assessment Software: Users Guide.
wise. the roots of the vouna banana Environmental Monitorina Sv

Fusarium Wilt. In this experiment, single
cases of infection occurred at random at
distances of several meters from previous
centers of infection although very low
incidence was observed in the area. F.
oxysporum f. cubense can be dispersed by
infection planting material, by contaminated
tools, soil, plant debris, an especially but
floodwater but such means could not have
been at work considering the time the planting
has existed. Although chlamydospores of the
fungus can withstand drought and survive in
dry soil for months and perhaps years this
remains to be ascertained in relation to
disease distribution along with the apparent
recovery of Fusarium sp. from air samples.


ANOMYMOUS. 2002. Comments on the
Australian Draft Import Risk Analysis
(IRA) Report on the Importation of Fresh
Banana from the Philippines. Policy
Discussion Paper, Department of
Agriculture, Quezon City. 16pp

ALLEN RN 1978. Spread of bunchy top
disease in established banana
plantations. Aust. J. Agric. Res. 29:1223-

BUDENHAGEN IW 1968. Banana diseases in
the Pacific area. FAO PI. Prot. Bull. 16:17-

S. 1989. Biological, control of bacterial wilt
of potatoes caused by Pseudomonas
solanacearum. Am. Potato J. 66:315-315-

CRESSIE N. 1993. Statistics for Spatial Data.
John Wiley & Sons, New York. 900 pp.

1AYWARD AC. 1991. Biology and
epidemiology of bacterial wilt caused by
Pseudomonas solanacearum. Annu. Rev.
Phytopathol. 29:65-87.

3BAL M, KUMAR J. 1986. Bacterial wilt in Fiji.
Annu. Rev. Phytopathol. 108. 25-27.

:ELMAN A, SEQUIERA L. 1965. Root-to-root
spread of Pseudomonas solanacearum.
Phytopathology 55:304-309.

Effects of intercropping potato on bacterial
wilt. Phil. Agric. 70:83-90.

nIEREDITH DS. 1970. Banana leaf spot
disease (Sigatoka) caused by
Mycosphaerella musicola Leach.
Phytopahtological Papers No. 11.
Commonwealth Mycological Institute. Kew,
Surrey, England. 147 pp.

'EDROSA JR. AM. 1993. Disease
management in commercial banana
plantations in the Philippines. In: N.G.
Tangonan (Ed.) Towards Making Pest and
Disease Management Relevant to Big and
Small Banana Growers. Proc. 1t PPS-
SMD National Symposium on Pests and
Diseases of Banana in the Philippines,
April 23-24, 1993, Davao City. pp. 15-28.

ZOPEROS NI, ATABUG RG. 1985. Status of
Moko and Panama Diseases of Banana in
the Philippines. In: Proceedings of the
International Seminar-Workshop on
Banana and Plantain Research and

ZOPEROS NI, MAGNAYE LV. 1991. Status of
banana diseases in the Philippines. In:
Valmayor, R.V., B.E. Umali and C.P.
Bejosano (Eds) Banana Diseases in Asia
and the Pacific: Proc. Regional Technical

Meeting on Diseases Affecting Banana anc
Plantain in Asia and the Pacific, Brisbane
Australia, 15-18 April 1991. 52-66 pp.

SAN JUAN MO. 1977. Endemic diseases of
bananas in the Philippines. In: Proc.
Symposium on Philippine Phytopathology
1917-1977, University of the Philippines at
Los Baihos, College, Laguna, Philippines.

Temporal dynamics of major banana
diseases in monocropping and
multicropping systems. Phil. Phytopathol.


a U



Figure 1. Monthly spatial maps of diseased (shadec
bunchy-top in a 24-row by 25-column se
Davao City. Maps show accumulation of
color in the succeeding months after May r
i I

Figure 1. Monthly spatial maps of diseased shadesc
bunchy-top in a 24-row by 25-column se
Davao City. Maps show accumulation of
color in the succeeding months after May re

i .........

I 0

ease from month to month in the same farm. New
esents the development of the disease.


W %


m mmr" "
m m

Figure 2. Monthly spatial maps of diseased (shadec
bunchy-top in a 24-row by 25-column se
Davao City. Maps show accumulation of
color in the succeeding months after May r(


I mm

.0m a

ma %
m m

m [ *

)locks) banana plants during an epidemic of banana
:ion in the multicropped system at Calinan District,
sease from month to month in the same farm. New
resents the development of the disease.

Umadhay and Raymundo


aI Nugget: 0.65785
4 8 Model: Spherical
S1.S Range: 12.92 meters
S4 Sill: 4.897
3"2 Anisop: 1

-20 6 12 6 -4 0 4 8 12 16 20

Figure 3. Variogram surface of banana bunchy-top in monocropping system.


SNugget: 5.033922
Model: Spherical
S" Range: 7
SSill: 2.1
i .. Anisop: 1

Figure 4. Variogram surface of banana bunchy-top in multicropping system.



0 a 12 is 2D L 2B w as

Fig. 5. Variogram graph (meters) of banana bunchy top
in monocropping system.



0 0 9 12

t5 18 21 2'

Fig. 6. Variogram graph (meters) of banana bunchy top
in multicropping system.

Spatial dynamics of banana





Umadhay and Raymundo



Figure 7. Monthly spatial maps of diseased (shaded blocks) plants during an epidemic of Moko disease in
a 24-row by 25-column section in monocropped system at Calinan District, Davao City. Maps
shows accumulation of disease from month to month in the same farm. New color means in the
succeeing months after May represents the development of the disease.





L* *" !'" '' i
ba&------- ----




ure 8. Monthly spatial maps of diseased ,shade
a 24-row by 25-column section in multi(
shows accumulation of disease from mor
succeeding months after May represents-t

______________ ____

~-l~lure M ont PI npa i h- i____________ ;s ad




\ I il


i -

locks) plants during an epidemic of Moko disease in
>ped system at Calinan District, Davao City. Maps
to month in the same farm. New color means in the
development of the disease.


Umadhay and Raymundo




Figure 10. Variogram surface of Moko disease in multicropping system.





50 -40 -,3 .20 -10 0 10 20 30 40 50

Figure 9. Variogram surface of Moko disease in monocropping system.

Umadhay and Raymundo


0o a 12 a a2 2 a a2 a
Fig. 11. Variogram graphImeters) of Moko disease in
monocropping system.

WIM rinD Mrtui*mal


0 S 12 a1 2

a2 4

Fig. 12. Variogram graph (meters) of Moko disease in
multicropping system.




:igure 13. Monthly spatial maps of Fusarium wilt dise;
25-column section in the monocroppped ,
accumulation of disease from month to me
months after May represents development o-



ad (shaded blocks) banana plants in a 24-row and
item at Calinan District, Davao City. Maps show
:h in the same farm. New color in the succeeding
ie disease.


Figure 14. Monthly spatial maps of Fusarium wilt dise;
25-column section in the multicropped sy
accumulation of disease from month to mo
months after May represents development of



d (shade blocks) banana plants in a 24-row and
n at Calinan District, Davao City. Maps show
in the same farm. New color in the succeeding



Supported by the Fiber Industry Developmer
research and Management of Abaca Diseases in
ZP-Japan Increased Food Production Program c
NAFC), Department of Agriculture, Diliman, Quezoi

1Professor, Department of Plant Pathology, I
,ollege,Laguna; 2Extension Unit Head and 4Re
Extension Unit Head and 501C Regional Directo
uthor: A.D. Raymundo; E-mal: { HYPERLINK "me

Estimated losses in fiber yield in thi
pesos as a result of the widespread occ
enormous. On a region-wide mean i
estimated yield loss in fiber yield was 8
The province of Sorsogon appeared to be
loss of Php9,458,893.40. Although I
incidence of only 2.83 percent, lower thai
Sur, it came in second in terms of loss,
account of the large hectarage planted of

In Eastern Visayas, the estimated fit
Php8,440,350. Northern Samar and Nort
with estimated fiber losses of 153,186 an
Php3,488,400, respectively. Southern Le
smaller area affected.

Key words: Bunchy-top, mosaic, abaca



Authority (FIDA) IPM III Project "Sustainable
col and Eastern Visayas" with funding from the
he National Agriculture and Fisheries Council

versity of the Philippines Los Bahos (UPLB),
)nal Director, FiDA Region 5. Legaspi City,
-IDA Region 8, Tacloban City (Corresponding
: billyray@laguna.net" )).

ficol Region and equivalent values in
rence of bunchy-top and mosaic were
ease incidence of 5.19 percent, the
,587.99 kg valued at Phpl8,338,935.78.
ie hardest hit with an equivalent pesos
tanduanes has an average disease
lose observed in Albay and Camarines
tich was valued at Php5,814,850.36 on

loss was 312,076 kg with a value of
rn Leyte sustained the highest losses,
116,280 kg valued at Php3,829,650 and
, has the lowest estimated loss due to

32 Raymundo et al.

reported that severity levels of abaca mosaic current average production, prevailing local fiber
significantly reduced the tensile strength, prices and other relevant pieces of information
biomass yield, fiber yield, plant height, and stalk were gathered. These were used in estimating
diameter of abaca plants as well as the gross reduction in fiber yield and losses in peso value.
income of farmers. He estimated a per hectare
annual loss of Php26,184.06 at high abaca RESULTS AND DISCUSSION
mosaic severity level.
Losses in Abaca Fiber Yield Due to Mosaic
It is possible, likewise, to estimate reduction and Bunchy-top in the Bicol Region
in fiber yield from associated studies in surveys
and mapping of both virus diseases This paper Estimated losses in fiber yield in the Bicol
reports on such approach in connection with the Region and equivalent values in pesos as a result
FIDA IPM III Project "Sustainable Research and of the widespread occurrence of bunchy-top and
Management of Abaca Diseases in Bicol and mosaic were enormous (Table 1). On a region-
Eastern Visayas (FIDA, 1995). wide mean disease incidence of 5.19 percent, the
estimated loss in fiber yield was 833,587.99 kg
MATERIALS AND METHODS valued at Php18,338,935.78. The province of
Sorsogon appeared to be the hardest hit with a
The data used in this analysis were obtained equivalent peso loss of 9,458,893.40. Although
from mapping operations in Bicol and Eastern Catanduanes has an average disease incidence of
Visayas. The whole regions of Bicol and only 2.83 percent, lower than those observed in
Eastern Visayas were targeted for mapping. Albay and Camarines Sur, it came second in
FIDA field technicians in all provinces of the terms of loss, which was valued at
region were involved in this activity after Php5,814,850.36 on account of the large
appropriate training in correct diagnosis based hectarage planted to abaca.
on visual symptoms and accurate sampling of
disease distribution. Losses in Abaca Fiber Yield Due to Mosaic
and Bunchy-top in Eastern Visayas
The methodology used in mapping is
discussed in detail in Raymundo et al (2001b) In Eastern Visayas, the estimated fiber loss
and Raymundo (1997). It is summarized as was 312,076 kg with a value of Php8,440,350
follows: The prevalence of the disease is (Table 2). Northern Samar and Northern Leyte
ascertained in every barangay (hamlet) for every sustained the highest losses, with estimated fiber
town of all provinces of the region by extensive losses of 153,186 and 116,280 kg valued at
surveys. As surveys have been undertaken in Php3,829,650 and Php3,488,400, respectively.
the past, current surveys are aimed primarily at Southern Leyte has the lowest estimated loss due
confirming prevalence. The degree of incidence to smaller area affected.
in affected areas is determined by disease
sampling. At the barangay level, three one- This report constitutes the first quantitative
hectare were selected. In each one-hectare estimation of losses due to bunchy-top and mosaic
area, the X-pattern of sampling was employed virus diseases from a field survey. In all likelihood,
with three 10 x 10m areas of each arm being the figures herein reported are underestimation as
rated for incidence. Data from the three areas the data on disease incidence sampling
were then averaged to obtain the incidence for represents the averages of sizeable areas within
each one-hectare area. The mean of the three the regions. Higher magnitudes of losses
one-hectare areas were recorded for the therefore in specific areas where disease
barangay. The disease incidence for a particular incidence has been known to be high are not
town was computed from the mean data from all reflected. The figures estimated from this survey,
the barangays. The provincial average however, are significant in the light of the
incidence was obtained from the data in all continuing spread of the diseases. In the early
towns, part of the last century, Calinisan (1934) and

In addition, data on magnitude of area
affected in each of the provinces in the regions,

Economic losses in abaca

Ocfemia and Celino (1938) reported that mosaic
incidence was low but about a decade later,
Reinking (1949) incidence in some abaca areas
reached100%. Consequently, losses in fiber
yield in heavily infected areas were estimated to
average 22 percent.

The estimated losses pertain only to fiber
yield. In most likelihood, reduction in fiber
quality was a consequence of certainty that
perhaps has a significant effect on farmers'
income. Agati (1953) reported that diseased
plants produced fewer, shorter, and weaker
fibers and matured longer than healthy plants.
Cruz (1954), likewise, mentioned that mosaic
affected tensile strength of abaca fibers. Dela
Cruz (2001) went on step further and measured
the effect of degree of disease severity on
tensile strength. He also reported yield losses
as high as 49 percent and 14 percent in terms of
total fiber yield and biomass yield, respectively,
under conditions of high disease severity.

From a practical point of view, estimates of
losses in yield and other characteristics are
benchmark information critical to formulating
disease management strategies. Along with a
clear insight into the epidemiological dynamics of
the diseases (Raymudo et al., 2001a; Raymundo
et al., 2001b), these estimates can be the basis
of a well-timed and location-specific eradication
program for sustainable management of bunchy-
top and mosaic.


AGATI JA. 1953. Report on the mosaic control
campaign in the Philippines. Dept. Agr. Nat.
Res., BPI, Manila. Mimeogr. Rpt. 28pp.

CALINISAN, MR. 1934. Notes On a suspected
"mosaic" of abaca in the Philippines. Phil. J.
Agric. 5:255-258.

study on the symptoms
Phil. J. Agric. 10:121-130.

A comprehensive
of abaca mosaic.

CRUZ, EE. 1954. Comparative study of
mosaicked ad non-mosaicked fibers of
abaca. Phil. J. Agric. 19:209-256.

DELA CRUZ CS. 2001. Epidemiology of mosaic
in abaca (Musa textiles Nee.) PhD Thesis,
College, Laguna, Philippines: UPLB.

FIDA. 1995. SustainAble research and
management of abaca diseases in Bicol and
Eastern Visayas. Project Operational Plan,
Fiber Industry and Development Authority,
Quezon City, Philippines 73pp.

KENT GC. 1954. Abaca mosaic. Phil. Agric.

OCFEMIA GO, CELINO MS. 1938. Transmission
of the abaca mosaic. Phil. Agric. 27:593-608.

RAYMUNDO AD. 1997. Epidemiology of abaca
virus diseases: Mapping disease spread and
its application to disease management by
roguing and replanting. Paper presented
during a technical training on The Abaca Plant,
Its Diseases and Vectors in preparation for the
implementation of the project component.
Disease Mapping and Eradication, under the
FIDA IPM III Program, Sustainable Research
and Management pf Abaca Diseases in the
Bicol and Eastern Visayas Regions, held on
Aug. 21-23, 1997 at FIDA Region 8, Tacloban
City and on Aug. 28-29, 1997 at FIDA Region
5, Legaspi City. (Looseleaf).

FABELLAR NG, BASIO NM. 2001a. analyzing
the devastating epidemics of abaca bunchy-top
and mosaic virus diseases in the Philippines.
Proc. 2001 Annual Convention of the Pest
Management Council of the Philippines, DA
Conventional Hall, Pili, Camarines Sur, May 2-

Mapping the spread of abaca bunchy-top and
mosaic diseases in the Bicol and Eastern
Visayas regions, Philippines. Phil. Agric.
Scientist 84:352-361.

ulcdVeU, rillpPililt iicillUs. ridllLl. LAb. lUrpll.

SAN JUAN MO. 1989. The bunchy-top disease
of abaca in the Philippines. History and
economic importance, pp.1-5. In: Proc First
National Symposium/Workshop on the
Bunchy-top Disease of Banana and Abaca,
1989, Davao city, Philippines.

Economic losses in abaca

Table 1. Economic analysis of the effect of bunchy-top and mosaic in the Bicol Region

Area Number Number Number Average Production Average
in of of of Percent in Bales Production
Province Hectare Farmer/ Barangay Munici- Disease at 125 kg Per Hectare
Cooperat palities Incidence 1998 1998

Expected Losses to
9unchy-top and
Mosaic in 19911
Fibers(kg) Pesos

Albay 4,431.30 2,342 106 15 6 10,772 303.86 80,790 1,777,380
Canarines 6,587.50 2,598 120 16 4.43 10,571 200.58 58,536.91 1,287.812
Camarines 976.70 874 79 10 J.03 47
Sorsogon 11,343.26 3,496 154 11 12.68 27,082 298.3 429,249.70 9,443,493.4
Catanduanes 19,053.61 13,243 113 14 2.83 74,717 490.17 264,311.38 5,814,850.52
Total 42,302.37 22,553 572 66 123,189 833,587.99 18,323,535.78
Mean 5.19 323.26

Losses in peso value was computed as follows: Production in bales was multiplied by 125 to obtain total production in kg. This figure
was multiplied by the average percent disease incidence on the assumption that infected plants are eradicated as done in the
program. The resulting figure was then multiplied by Php22 to get the peso value.

Table 2. Economic analysis of the effect of bunchy-top and mosaic in Eastem Visayas.

Number of Number Estimated Estimated Estimated Percent Actual Ave. Yield/ Estimated Estimated
Name of Municipa- of Brgy Effective Number Number of Disease Area HatAnnum Fiber loss Value
Province cities Affected Area ofHils hills Incidence Affected (kg) (pesos)'
Affected (has.) Infected (has.)

1,356.15 3,390,380 290,700 8.57
44.08 110,200 28,525 25.88
3,757.86 9.394,650 638,275 6.79

15 172.62 431,550

130,000 30.12

140 5,330.71 13,326,780 1,087,500


116.28 1,000
11.41 1.000
255.31 600

116,280 3,488.400
11,410 342,300
153.186 3,829,650

52 600 31,200 780,000


312,076 8,440.350

N. Leyte 5
S. Leyte 2
Northern 12
W.estem 5
Total 24

Losses in peso value was computed as follows: Estimated effective area of abaca was multiplied by the percent disease incidence to
obtain the actual area affected in hectares which was then multipled by the average yield per hectare to get the estimated fiber loss in
the province on the assumption that infected plants area eradicated as done in the program. The resulting figure was then multiplied
by either Php30 for Leyte or Php25 for Samar provinces to obtain the peso value.



Supported by the Philippines Sugar Research Institute (PHILSUGIN). Portion of the F
Jissertation of the senior author.

'University Researcher, 4Professor, Institute of Plant Breeding, 2Associate Professor, Departme
DI--+t D-+hl^^\r arn 3A i n\ DrfAa cn 'r Klti n l Or^r Dr,4i.in t n O'nr,+r rfll ers f An riu^i il+ ra I I nit

*1III uu vaya IvJv.SJ I II fl,

)ugn conc
) RSD ini
I the varie

1982). Yield

a given variety ana soil moisture DuI is not a c
3uzman, 1985). Reduction in yield Consequently, botl
ease increases with the number of assessment of cult
to increased disease incidence The production of r
961). Yield reduction can be up to nodes of mature st;

f the immature nodal tissue of young shoots are MATERIALS AND METHODS
ie only diagnosis features of the disease but
iese are not always associated with RSD- Survey of Different Sugarcane
infected plants. Mill Districts

RSD is caused by a small, xylem-inhabiting Trips to different sugarcane growing are
oryneform, nutritionally fastidious bacterium the Philippines such as Negros, Iloilo City, (
eifsonia xyli subsp xyli (Davis) Evtushenko et al Ormoc, Bukidnon, Davao, Cagayan, T;
?000) formerly Clavibacter xyli subsp. xyli. The Pampanga, Batangas and Camarines Sur
acterium is mechanically transmitted at harvest made. Twenty-five mill districts in the Philip
Sthe subsequent plant cane and stubble or (14 in Negros and Panay, 5 in Luzon, 3 in Ea
atoon crops. Taylor et al (1988) observed that Visayas and 2 in Mindanao) were visited and .
:SD was efficiently transmitted when the cane planted to sugarcane were assessed. Likewise
ras cut above the ground level. The ease of variety picture in each district was determ
mechanical transmission of Lxx in sugarcane Arrangement with the different Philil
created rapid secondary (within crop) spread of Sugarcane Research Institute Foundation, Inc
ZSD in susceptible cultivars of sugarcane. Soil District Development Cooperative (PHISI
ansmission of the pathogen has been reported MDDC) coordinators regarding collection
\utrey et al, 1991; Bailey and Tough, 1991) sugarcane samples was done.
thich may help explain the failure of
hytosanitation to control the disease. Collection of Samples

The disease can be controlled by heat Sample collection was done following
eatment of planting materials and this method procedure of Irvine and Irey (1991). Field san
increased both the amount and rate of of sugarcane consisted of ten stalks. Samples
ermination of canes and resulted in fewer seed randomly collected from ten different rows
ane with RSD symptoms but did not eliminate each end of the field. Stalks that were uninfi
ie disease. Cleaning the knives also greatly with other diseases such as smut and d
educed the rate of spread and fewer stalks mildew, and free of borer damage were sele
ecame infected when the spreader plants were Stalks with five internodes from the basal pc
carefully removed and the knives were were collected and adhering leaf sheath
ioroughly cleaned. Another method is through removed. Each sample was labeled with v;
ie use of resistant varieties but these are rare in name, place of collection, age and type of :
ugarcane. In the Philippines, very little whether ratoon or new plant. Samples
formation is available regarding the disease, transported to the laboratory for assay.
Though the occurrence of RSD has been
)ported as early as 1955 in Negros (Lopez, Sample Preparation
963) very minimal attempts had been made to
conduct studies that can provide basic Surface sterilization was done by thorol
formation about the disease, its distribution scrubbing the infected stalks with dete
nd the causal organism. and rinsing in running water. After washing, E
were cut into 3-in portion and dipped in
This study was conducted at the Plant sodium hypochlorite for 3 min to remove su
'athology Laboratory of the Institute of Plant grime. Samples were washed in three cha
Breeding, UPLB and some portions at the of sterile distilled water, blot-dried and brc
'athology Laboratory of the PHILSUGIN inside the isolation room. Inside the room
breeding Station at Victorias City, Negros bark was removed and the tissue was
accidentall from 1997 to 2001 to survey the inside the laminar flow bench. The tissue
ccurrence and distribution of RSD in the then immersed in 10% sodium hypochlorite
different sugarcane production areas in the 2 min., rinsed in three changes of sterile diE

Geographic distribution of ratoon 37

carried out using a sterilized pliers. Extraction Batangas). The area with RSD was higher in
sap was collected in sterile centrifuge and stored Nasugbu, as compared with Balayan wherein only
and stored at 40C and brought to the laboratory 12 out of 53 fields yielded positive to RSD
for processing. Samples from Negros and Panay bacterium. The lowest frequency was recorded in
were processed at VMC, Victorias City, Negros Tarlac (16%).
Occidental. The rest of the samples was
assayed at the Plant Pathology laboratory, In Negros, the highest frequency of the
Institute of Plant Breeding, UPLB. disease was 90%, which was observed from
Biscom mill district. This was followed by Murcia
Processing of Samples and Bais wherein 79% and 71% of the areas,
respectively, had RSD. Less than 50% of the field
The samples were processed according to in Dacongcogon, Lopez and La Carlota, Negros
the dot blot immunoassay (DBIA) method Occidental had RSD but the areas in Lopez
(Dolores et al., 1998; Davis et al, 1984). Ten (10) exhibited the lowest incidence of the disease
ul sap was blotted on the nitrocellulose (36%). Low frequency of the disease was
membrane surface and incubated overnight at recorded from Iloilo samples, 47% from Passi
room temperature. The membranes were while Pilar has 13%, The highest number of fields
serologically processed (Harisson and Davis, surveyed was in Victorias and it was recorded that
1988) by first treating them with a protein 58% of the area had RSD.
reagent to block nonspecific binding sites for
antibodies. The membranes were then incubated In Eastern Visayas, 400 fields were surveyed
for 1 hr in rabbit antiserum specific for Lxx in Cebu and of these, 110 yielded positive giving a
produced at IPB, UPLB. The membranes were disease frequency of 27.5%. A smaller number of
then rinsed with buffer and incubated for 1 hr fields were surveyed from Ormoc but a disease
with a second antibody conjugated with alkaline frequency of 22% was recorded.
phosphatase. This second antibody was specific
for rabbit antibodies and attached to the Lxx In Davao, 36 areas covering seven
antibody. Lastly, NBT/BCIP was added. The municipalities were surveyed. It was noted that
membranes were rinsed in sodium hypochlorite only one municipality, i.e. Magsaysay area, had no
to remove a general violet to bluish discoloration. RSD and the frequency of the disease across
The membranes were rinsed in water to remove municipalities was 65%.
excess sodium hypochlorite and dried at room
temperature. Positive samples showed violet to Incidence of RSD in Different Municipalities
blue color while the negative remained colorless.
In Luzon, survey was confined to five
RESULTS AND DISCUSSION sugarcane growing provinces, namely, Batangas,
Pampanga, Tarlac, Cagayan and Camarines Sur.
Distribution of RSD Among Sixteen municipalities on Batangas were surveyed
Sugarcane Mill Districts for the presence of the disease ad of these,
nine had RSD and the rest had none (Fig. 2).
Results of assay of sugarcane as samples Almost all varieties grown in Calatagan, Balayan
showed that RSD is present in all districts except and Lian were positive to RSD (Table 2).
in Cagayan (Fig. 1). The distribution, however, Sugarcane samples collected form Lemery,
varied among and within each district and the Rosaio, Taal, San Luis, San Pascual, Alitagtag,
incidence differed among and within varieties Ibaan and Rosario had no RSD. All samples
(Table 1). Pampanga was observed to have the from these places consistently yielded negative
highest frequency of RSD across cultivars reaction regardless of variety tested. Only one
yielding a total of 79% or 38 out of 48 field sample each from Padre Garcia, Sta. Teresita and
surveyed. This was followed by Camarines Sur Tuy yielded positive result to DBIA. It was
giving a frequency of 64% although only 11 interestingly noted that VMC 84-524 consistently
fields were surveyed. It was interesting to note exhibited negative results even though the
that the incidence of the disease varied between samples were taken form different municipalities.
two adjacent mill districts (Balayan and In Pampanga, the disease was present in all

(Fig. 3). Similarly, of the nine 'eight municipalities surveyed in Davao hf
cities surveyed for RSD in Tarlac, only disease (Fig. 9). These were Hagono!
from Gerona had negative results )Magsaysay areas. On the contrary, all va
;s of the varieties assayed (Fig. 4).\ from Digos were positive in the assay, ind
'ere some areas, though, like Victoria the presence of the disease. Only one variety
nly one to two out of several varieties Matanao, Bansalan and Malalag areas h
are positive. It was also observed that all RSD.
Ilities that grow mixed varieties had RSD
incidence ranged form 6-19%. Likewise, Incidence of RSD in Commercial Cultiv
four sugarcane growing municipalities in
es Sur had RSD (Fig. 5). These were All commercial varieties tested were posi
li and Goa. In Naga, only VMC 86-550 the bacterium. The incidence, however,
cane multiplication nursery was indexed from area to another. In Negros, all varietiE
was negative to the bacterium. Likewise, were assayed in Bais and Murcia districts hai
licipalities namely Tuao and Piat, were while in First Farmers Holdings, only one
I in Cagayan and RSD was detected yielded negative result to ELISA indicatir
en varieties collected, absence of the bacterium. Varieties from
Biscom and Sonedco showed high frequency
astern Visayas, samples were collected disease yielding a frequency of the disease
moc and Cebu (Table 2). Of the 61 locations yielding a frequency of 77, 671 anc
collected from Leyte, varieties that came respectively. In Victoria mill district only 3
ianga were free of the disease. RSD the varieties assayed for RSD was positive M
sent in four out of seven and one out of Hawaiian-Philippines, 50% incidence of
rieties collected from Ormoc and Leyte, across cultivars was recorded.
/e (Fig. 6). On the other hand, six
ilities surveyed in northern part of Cebu In Cebu, 18 varieties were widely grown
) (Fig. 7) and the incidence ranged from these, 15 exhibited susceptibility to the d
depending on the variety tested. Results representing a frequency of 83%, regardli
that there was sporadic occurrence of location. In Ormoc, ten widely grown varieties;
different areas. Some varieties that tested and five of these of these had RSD.
positive reaction in one area were
in another area. Only Phil 76-16, which Eleven commercial varieties from Davac
imercially grown in three municipalities, samples form different locations and ii
itly yielded negative reaction indicating gathered that six of these were positive
=nce of the bacterium from the samples bacterium. In Bukidnon, 105 samples repres
13 varieties were assayed and 10 of these \
positive results.
ity municipalities in Negros Island were
I for RSD and results showed that the High frequency of the disease in comn
was present in all the areas surveyed varieties was recorded in Nasugbu and
ry in Pamplona, Isabela, Mabinay, Bais, All the varieties tested form these area,
and Murcia (Fig. 8). All commercial the disease. In Pampanga and Tarlac, i
planted in these municipalities were noted that majority of the varieties
o Lxx (Table 2). The lowest incidence of unidentified. It was observed that in Pamp
; noted in Binalbagan where only one out 83% of the fields planted to unidentifi
varieties tested had RSD. mixed varieties was infected with the disease
Tarlac only 20% of unidentified varieties as
was detected in nine municipalities in The results of the survey also showed that
ut of 11 varieties indexed for RSD, only had the most number of commercial va
id strong positive reaction while the rest and only 2% or four out of sixteen varieties
native. RSD. Similarly, low incidence of the disease

- l II uaiaii i Ia i Jl O. t,' I LI IV I1
is grown in the area, only six were positive.

D was observed to be asymmetrically
cited in commercial varieties. In Negros,
ymmetric distribution was apparent in Phil
In Bais-Ursumco areas, for examples,
ph the disease was present in all varieties
There were some fields planted to Phil 8-
at were positive to the diseases but others
lot. It was also observed that of the 13
!s planted in Maao mill district, three
s consistently yielded negative reaction to
although they were collected from different
las. They were VMC67-611, VMC87-599
il 88-39.

Above observation holds true even
geographic region. During the course of
vey, Phil 80-13 was the most widely grown
in Visayas and Midnanao. In Davao, it
)served that 73% of the areas planted to
iety had RSD while in Negros and Eastern
s, a frequency of 68 and 42% was
id, respectively. Phil 74-64 was also
cultivated in Negros and Panay, Eastern
s, Luzon and Davao. It was gathered that
vas high incidence of RSD in Phil74-64
in Eastern Visayas (83%) and Negros
low incidence in Eastern Visayas but
ted when samples form Davao were
d. The newly released, high yielding
V86-550 had 100% RSD in Davao, 71%
ros/Panay, 53% in Eastern Visayas but
ted in Luzon and Bukidnon. Phil 84-77
;o susceptible to the disease. A disease
icy of '12, 73 and 100% was recorded in
1 Visayas, Negros/Panay, respectively but
s from Luzon yielded negative reaction to
:terium. Similarly, the bacterium was not
d from samples of cultivar P8839 collected
Eastern Visayas and Davao, but high
ce was recorded from Negros (40%) and

ng DBIA, RSD was detected from samples
*d from the different mill districts in Luzon,
; and Mindanao. This finding indicated
ie disease was now well distributed
iout the sugarcane growing areas in the
. Surveys of RSD in the past were based
nptomatology and they were mostly
rl in Nonrnc The nrinrinal eImntnm i icrl

was the reddish to orange vascular bundle<
at the nodes of split stalks. Bas
symptomatology, Lopez (1963) reported
1955, King claimed that RSD was already a
some of the varieties grown in Northern
After 7 years, the presence of the disease i
important commercial varieties in Victor
district was observed by Mesa (1970). 1
Mesa et al. also surveyed Don Pedro mill d
Nasugbu, Batangas and noted that Phil 56-:
RSD and the degree ranged from 6 to 2C
observing six farms and examining a total
stalks. Husmillo et al (1966) also report
incidence of the disease in Hawaiian-Philip

At present, almost all sugarcane-i
municipalities in Negros, Panay, Cebu,
Davao, Batangas, Pampanga, Tarlai
Camarines Sur except in Cagayan were po
the disease. The possibility that the diseE
been present in all mill districts since early
not be discounted. This could be due to
that in the past, survey were based sc
symptomatology, hence, the true picture
disease distribution was not well accountec
was proven that field diagnosis of disease
was very difficult because the disease
cause any external symptom such as wilti
rotting and the bacterium could not be dete
bacterial streaming or "ooze" test as being r
done in other plant pathogenic bacteria. S
or marked reduction in growth was also ass
with stress like drought, poor fertility o
causes. Vascular discoloration, an
symptom may be ephemeral or absent ir
clones (Gillaspie et al, 1966; Steindl, 1961),
unreliable (Gillaspie and Teakle, 1989).
possible that during the field surveys d
sugarcane workers, areas and varieties th;
found negative to RSD were not truly free
disease. Bacterial cells could have been pr
seedpieces examined but did not indicate
discoloration due to low concentration.
Bacterial cells could have served as in
source for eventual spread of the disease.
:he bacterium was readily transmitted throu(
from diseased plants, the disease coul(
spread from districts with RSD to areas v
Nas not yet present through exchange of 1
materials. Planters and researchers wh

Ily without bothering to inspect the cul
nes, whether diseased or not. Steindl fro
Dean (194) noted that the widespread ins
of the disease could be largely An
shipment of infected cuttings. In the dis
ivement of seedcanes from place to thr
lot properly monitored and inspection be
only on symptomatology. Another thr
ason for the spread of the disease (1c
nunicipality to another was through mE
id agricultural equipment because the sul
was readily transmitted through cul
means. Bailey and Tough (1991)
that the pathogen could be
y transmitted from sugarcane to thr
on the blades of equipment used to col
I harvest crops. cal
ease was found to be well distributed is
the sugarcane growing areas of the m,
since the disease has the potential to ind
-e loss when there is a combination of
;e incidence and severe stresses, ba
need to implement integrated RSD ol
it strategies. Initial experiments have the
at most of the commercial varieties of dis
iave the potential to harbor the RSD RS
and have the capability to become of
ifection, it is therefore recommended hol
Materials to be micropropagated or dis
3 commercial growers be indexed for iml
um to limit the distribution and spread im
canes. Infected materials should be Fu
-ated to eliminate the bacterium. The be
easily transmitted by contaminated tre
lents, hence, it is important that all cor
be disinfected before and after use. pla
i, breeding for RSD resistance should infe
red.. Management through heat still
nd sanitation is quite an expensive dis
ram because it should be done every
ason to prevent the recurrence of
The use of resistant variety, if
> still the most practical means to AU
:he disease, through exchange of
:erials. Planters and researchers who
3tive in terns of variety adaptation
acquire seedcanes from other areas,
internationally without bothering to BA
quality of canes, whether diseased or
(1961) and Dean (1984) noted that
ad distribution of the disease could

L I~Y I L4 U l*% A U I* 11J II* I *J I
igs. In the country, movement of seedcan
place to place was not properly monitored a
action was based only symptomatoloc
her probable reason for the spread of t
ise from one municipality to another w
gh contaminated agricultural equipment
use the bacterium was readily transmit,
gh mechanical means. Bailey and Tou!
1) observed that the pathogen could
ianically transmitted from sugarcane
rcane on the blades of equipment used
ate and harvest crops.

he disease was found to be well distribute
ghout the sugarcane growing areas of t
try and since the disease has the potential
3 severe losses when there is a combination
disease incidence and severe stresses, the
a need to implement integrated Rc
igement strategies. Initial experiments ha
ated that most of the commercial varieties
rcane have the potential to harbor the Rc
.rium, and have the capability to becor
:e of infection, it is therefore recommend,
planting materials to be micropropagated
buted to commercial growers be indexed 1
bacterium to limit the distribution and spre;
seases canes. Infected materials should
rater treated to eliminate the bacterium. TI
ise is easily transmitted by contaminated fai
,ments, hence, it is important that
.ments be disinfected before and after us
ermore, breeding for RSD resistance shoL
considered. Management through he
nent and sanitation is quite an expensi
ol program because it should be done eve
ng season to prevent the recurrence
:ion. The use of resistant variety, if available,
he most practical means of managing tl


ansmission of the RSD bacterium Clavibact
/li subsp xyli. Sugarcane 6:5-6.

EY RA, TOUGH SA. 1991. Mechanisms
fection of sugarcane by ratoon stuntir
sease bacterium Cxx. Sugarcane 6:5.

A R Af" IR A- -rt

-iARRIS RW. 1984. Clavibacter: A new gent
containing some phytopathogenic corynefor
bacteria, including Clavibacter xyli subsp. x.
3p. nov. and Clavibacter xyli subs
:ynodontis subsp. nov., pathogens that cau,
*atoon stunting disease of sugarcane ar
Bermuda grass stunting disease. Int. J. Sys
3acteriol. 34:107-117.

kN JL. 1983. Single-stool plots for estimatir
relative yield losses caused by ratoc
stunting disease of sugarcane. Plant Di

electionn of ratoon stunting disease
sugarcane by serological methods. In: Pro
t5t PHILSUTECH Convention, Cebu Cit
\ug. 6-11, 1998.

SA, COLE, JR, TIEDJE JM. 2000. Leifson
poae gen nov. sp. nov. Isolated froi
nematode galls on Poa annua ar
reclassification of Corynebacteriu,
aquaticum Leifson. 1992 as Leifson,
aquatica (ex Leifson 1962) gen. Nov., non
Rev., comb. nov and Clavibacter xyli Dav
et al. 1984 with two subspecies as Lefson,
xyli (Davis et al, 1984) gen. Nov. coml
Nov. Int. J. Syst. Bacteriol. 50:371-380.

1966. Ratoon stunting vines. Assa
technique and partial purification
Phytopathology 56:1426-1427.

stunting disease. I C. Ricaud, B.T. Egar
A.G. Gillaspie, Jr. and C.G. Hughes (Eds
Diseases of Sugarcane. Major Disease,
Elsevier Sci. Pub. Amsterdam. pp. 59-80.

Hawaiian-Philippine Mill District.
presented at 27th PMCP Conv., Da,
May 7-10, 1996.

IRVINE JE, IREY MS. 1991. A technique
survey for ratoon stunting disease
Inter-American Sugarcane Seminar.

1982. Cane yield response to ratoon
disease. Int. Sugar J. 84:131-133.

LOPEZ M. 1963. Ratoon stunting dis
sugarcane. Proc. Philsutech. 8: 45-4

Sugarcane disease of the worli
Elsevier Pub. Co. NY 542 p.

MESA RC. 1970. Ratoon stunting c
Victorias mill district. Proc. Philsutei

STEINDL RL. 1961. Ratoon stunting
Pages 433-453 In: J.P. martin. E.V.
C.G. Hughes (Eds). Sugarcane di
the world. Vol. 1. Elsevier I
Amsterdam. 542 p.

Harvester transmission of leaf ,
ratoon stunting disease: Demonsti
evaluation of methods for decent
Sugarcane 4:11-14.

to disinfect tools in order to limit the
ratoon stunting disease of sugai
Proc. ISSCT 19:332-335.

42 Dela Cueva et al.

Table 1. Incidence of ratoon stunting disease (RSD) in the different sugarcane mill districts of the

Mill District No. of Fields No. of Fields % RSD Incidence
Sampled Positive to RSD
Balayan, Batangas 53 12 23
Nasugbu, Batangas 58 26 45
Pampanga 48 38 79
Cagayan 7 0 0
Camarines Sur 11 7 64
Tarlac 219 36 16
Bais 80 57 71
Hawaiian Phils 14 7 50
SONEDCO 22 12 54
Dacongcogon 28 11 39
Lopez 33 12 36
BISCOM 21 19 90
La Carlota 24 10 42.
Bacolod-Murcia 42 33 79
Maao 43 27 63
First Farmers Holding Corp 6 5 83
Victorias 153 90 59
Ormoc-Kananga 45 10 22
Bogo-Medellin & Durano III 400 110 28
Passi 17 8 47
Pilar 15 2 13


78 120


Geographic distribution of ratoon

Table 2. Incidence of ratoon stunting disease (RSD) in commercial sugarcane varieties from
different areas in the Philippines

Luzon Mindanao

Luzon Mindanao

33 0


1. Phil 80-13

2. Phil 74-64

3. VMC 76-529

4. Phil 85-83

5. Ohil 77-07

6. Phi 71-39

7. Phil 89-43

8. VMC 86-550

9. Phil 84-77

10. Phil 56-226

11. Phil 88-39

12. VMC 87-95

13. VMC 87-599

14. Mixed Var.















Disease Incidence (%)
Negros/Panay Eastern Visayas
68 42

50 83


59 10

35 40


29 33

71 53

73 12

75 15

44 0

42 34

27 50



25 0




Figure 1. Geographic distribution of ratoor


--Camarines Sur




" -Davao del Sur

hunting disease (RSD) in the Philippines.

Geograhic distribution of ratoon


Figure 2. Map of Batangas showing the distribution
of ratoon stunting disease of sugarcane.

Figure 4. Map of Tarlac showing distribution of
ratoon stunting disease of sugarcane.

Figure 3. Map of Pampanga showing the distribution
of ratoon stunting disease of sugarcane.

'"'/" "

Figure 5. Map of Camarines Sur showing distribution
of ratoon stunting disease of sugarcane.



I (




Dela Cueva et al.

cea jww


f **--+ II

^ 1 a-" i

Figure 6. Map of Leyte showing the distribution of
ratoon stunting disease in sugarcane
growing areas.

Figure 8. Map of Negros showing the distribution
of ratoon stunting disease in sugarcane
growing areas.

Figure 7 Map of Cebu showing distribution of
ratoon stunting disease in sugarcane
growing areas.


Figure 9. Map of Davao showing the distribution of
ratoon stunting disease in sugarcane
growing areas.







Associate Professor, Department of Pest
e University, Muhoz, Nueva Ecija 3120 Phi
'flanzenpathologie und Pflazenschutz, Gec
100, Germany.

Histological study on the infect
Colletotrichum gloeosporioides was i
250 as the staining solution. Initial
out germ tubes 6 hr after inoculation
globose appressoria. At 24 hr, ti
appressoria. The appressoria formed
peg directly toward the host's epider
hr, filamentous primary hyphae d
intracellular mycelium and colonized
whitish, oval and water-soaked lesio
and ramified through the host tissue,
acervuli by 96 hr. At 120 hr, orange r

words: Histology, Colletotrichum gloeospor


n February 2000 and 2001 when rain wa
fy and humidity was high, an outbreak (
ingly unusual and uniformly distribute
ase of onion occurred in Nueva Ecija an
r onion-growing provinces in Luzon in th
ppines causing yield losses of as high a
00% in almost all of the fields. The disease
diagnosed as anthracnose/twister of onio
;ed by Colletotrichum gloeosporioide
erto et al. 2002). The damage to the industry
so high such that it warranted immediate
stigation of the nature, causes an
agement of the disease. Though the typic,
:tion process of C. gloeosporioides are we
blished in other cultivars, no studies hav
1 reported so far on the histological aspect
the interaction between onion and C

"his histopathological study was undertaken
provide information on the mode o
!tration, establishment of infection,



management, College of Agriculture, Centra
pines; Professor and Associate Professor,
August-Universitat, Gottingen, Grisebachstr

i of susceptible cultivar of onion
nducted using Coomassie Brilliant Blue
penetration events showed conidia sendi
After 12 hr, the germ tubes started to.foi
y developed further into fully matur
ppressorial cones and sent out penetrati
al cells 36 to 48 hr after inoculation. At
eloped from the infection peg as
their host cells leading to the formation
. Necrotropic secondary hyphae appear
ith intercellularly and intracellularly to foi
cilaginous spore matrix formed on the Ic

des, onion

subsequent development of the hypha w
host tissue and relative duration on the
phases of infection process of C. gloeosp
in onion leaf tissues.


Sixty-day-old potted yellow onion cul
Rushmore) was used for inoculation. T"
of C. gloeosporioides used throughout
was isolated from infected onion plants
from Nueva Ecija onion-growing area ai
in acidified PDA (pH 6.5) at 250C in
darkness for 14 days. To improve lea
wettability, one drop of Tween 80 was
the spore suspension and leaves were
lightly with camel's paint brush prior to in(
The spore suspension (2.5x106 spores
sprayed on the surface of the leaves L
point of saturation, covered with moisten
bag and sealed at the base of the pot
were kept in Mytron WB750 14-L climatic
to near 100% relative humidity at 27-2f
days with 12 hr alternating light and darkr

Alberto et al.

leaf samples were excised from the potted plants
at 6, 12, 24, 36, 48, 72, 96 and 120 hr after

Excised leaf samples were cleared in an
ethanol-chloroform-15% trichloroacetic acid
(74:25:1 v/v) clearing solution for a minimum of
12 hr at room temperature. The cleared leaves
were stained with one volume of 15%
trichloroacetic acid in water and 0.6%
Coomassie Brilliant Blue R-250 (Serva,
Heidelberg, West Germany) in 99% methanol
preparation (6 to 24 hr, 15 min, 36 to 48 hr, 30
min and 72 to 120 hr, 45 min). Stained leaf
samples were washed in water in two changes
and blot dried. The stained samples were
mounted on glass slides with cover glass using
glacial acetic acid-glycerol-water (5:20:75 v/v)
solution as the mounting medium (Wolf and Frid,
1981). The preparations were sealed with nail
varnish, examined and photographed with Leica
Wild MPS 48 light microscope.


Germination of Spores and Formation
of Appressoria

Six hr after inoculation, the ungerminated
conidioSpores (Fig. la) germinated after six hr
after inoculation and sent out long germ tube at
one end of the cell (Fig. Ib) and grew laterally on
epidermal surface with no apparent direction
toward stomata similar to the observations
made in papaya fruit (Chau and Alvarez, 1983),
alfalfa (Porto et al. 1988) and watermelon
(Anderson and Walker, 1962), Though
occasionally observed to be penetrating stomatal
cavities, such phenomenon, however, showed
that stomatal cavities do not appear to be the
usual site of entry.

Formation of appressoria at the tip of the
germ tube was observed at 12 hr after
inoculation (Fig. 1c) and continued to develop
into mature appressoria 24 hr thereafter (Fig.
1d). No stomatal penetration was observed even
when conidia and appressoria were attached to
the guard cells. The appressoria were dark
brown, round with a diameter slightly bigger than
the width of the conidia. They had a thin circular
zone at the base and formed into a cone which
was extended and in immediate contact with the

epidermal layer (Fig. 1d). The cone which is
used to identify structures produced by C.
lindemuthianum (Mercer et al. 1971) was also
observed in this study. The zone was believed
to be the appressorial pore which provided an
opening for the emerging infection peg
(Bergstrom and Nicholson, 1999). However, not
all of the germinated conidia produced long germ
tubes and appressoria.

Penetration and Development
of Infection Process

An infection peg emerged through the pore
and directly penetrated the host cell wall between
36 hr and 48 hr after inoculation (Fig. 2a). The
infection hypha did not cause any apparent
depression on the cuticle during penetration,
suggesting that penetration is more of enzymatic
in action and restricted only to that area adjacent
to the tip of infection hypha (Brown, 1977). The
production of enzyme i.e. cutinases, cellulases,
pectinases and polygalacturonases could account
for the degradation of cutin components of the
plant cuticle and host cell wall materials
(Bergstrom and Nicholson, 1999). The formation
of infection vesicle was not observed as what has
been described by Bergstrom and Nicholson
(1999) in corn. Though papilla was not observed,
such structure was reported, however, in other
hosts e.g. tangerines which makes C.
gloeosporioides a typical intercellular pathogen
that does not kill cells in advance of invasion soon
after penetration (Brown, 1977). At 72 hr after
inoculation, the fungus formed primary hyphae
from the infection peg and grew intercellularly
(Fig. 2b) and extended further to form larger
hypha allowing the fungus greater access to
nutrients from the host cell. The fungus grew
further and colonized other surrounding cells. It
was also at this stage when small whitish water-
soaked lesions appeared (Fig. 2c). Extensive
mycelial growth was also observed on the outer
surface of the host.

Symptom development

Numerous secondary mycelia and knots of
hypha were observed 72 hr after inoculation
which formed into stroma and gave rise to
numerous short conidiophores and then to
masses of conidia which formed into acervu\i at
96 hr after inoculation (Fig. 3a), an observation
similar to C. orbiculare in watermelon (Anderson

aginous spore matrix appeared (Fig. 3b
i developed further into black acervul
ged in concentric rings and necrotic area,
Affected portion of the leaf.


002. Anthracnose: Serious disease a
nion. Poster presentation. IPM CRSI
002 Symp. Tech. Comm. Mtg.,and Year 1(
planning Workshop. Virginia Tech
lacksburg, VA, USA, May 15-19, 2002.

RSON JL, WALKER JC. 1962. Histology c
watermelonn anthracnose. Phytopatholog

he biology of corn anthracnose. Plar
disease 63(7):596-608.

WN GE. 1977. Ultrastructure c
enetration of ethylene-degreened Robinsol
ingerine by Colletotrichum gloeosporioide,
hytopathology 67:315-320.

U KF, ALVAREZ AM. 1983. A histologiE
tudy of anthracnose on Carica papayE
hytopathology 73(8):1113-1116.

1971. Initial infection of Phaseolus vu
Colletotrichum lindemuthianum. Page
389. In: T.F. Preece and C.H. Di
(Eds.) Ecology of Leaf
Microorganisms Academic Press,

G. 1988. Histopathology of Colletc
trifolii on alfalfa. Phytopathology 78

WOLF G, FRID F. 1981. A rapid
method for Erysiphe f. sp. hordei in
whole barley leaves with a protein.
dye. Phytopathology 71:596-598.


This research was supported by the
fur Pfllanzenpathologie und Pflllllazel
Georg-August-Universitat Gc
Grisebachstrasse 6, D-3400, G(


Figure 1. Conidiospore germination and ap
gloeosporioides in onion leaf. a.
conidia, c. Germinated conidia sl
d. Germinated conidium with tw

... ...

issorium formation of Colletotrichum
germinated conidia, b. Germinated
'ing early formation of appressoriurh,
erm tubes and matured appressorium.

Figure 2. Penetration and tissue colonizatic
appressorium sending out infectic
intercellular mycelia, c. Whitish \

, u
HB^^,i! i ..

)f Colletotrichum gloeosporioides. a. Matured
,eg penetrating directly into the cuticle, b.
sr-soaked lesions.

Iv U S B

DAVAO CITY ON MAY 8-10, 2002

)RAL PRESENTATION Ishiyama) Swings et al. Bacterial blight
one of the major constraints on hy
geographic Distribution and Genetic production. Resistance to rice bacter
Diversity of Leifsonia xyll subsp. xyll. The disease of five maintainer (B) lines use
mause of Ratoon Stunting Disease of rice production which showed susce
Sugarcane in the Philippines. FM delay Cueva, majority of Philippine races X. o. p\
WP Natural, RG Bayot, EMT Mendoza and LL were improved. Pyramids of two of thr
lag (UPLB) as well as single Xa4, Xa7 and Xa
introgressed into these lines via mar
Isolation of the causal bacterium of backcrossing.
atoon stunting disease (RSD) of sugarcane was RFLP marker G1091 in chrome
lone. The colonies were very small, circular with and three other PCR-based markers
entire margins, convex, glistening, butyrous and the Xa7, namely: AFLP31, AFLP1415,
lave rough surface. The colonies remained non- and STS marker of the Xa21 gene
)igmented even after 2 weeks of incubation, domain) was used to facilitate the del
A total of 93 samples were filter-sterilized Xa7 and Xa21 in the backcross progei
ind streaked onto sugarcane medium to isolate three new PCR markers especially ST
he RSD bacterium. After several attempts, pure P3 had improved marker-aided selectic
:ultures of 25 RSD isolates were obtained. Xa7 gene compared to RFLP marker G
Confirmatory tests using Gram staining, PCM B lines containing gene pyrar
ind DBIA revealed that the bacterium was much shorter lesions indicating an
.eifsonia xyli subsp. xyfi. DNA of the different resistance to bacterial blight and
solates was extracted and tested by polymerase resistance spectrum to X. o. pv. oryz
;hain reaction (PCR) using Lxx specific primers. compared to those containing single gel
kgarose gel electrophoresis of the PCR PCR-RGA fingerprinting, which
productss yielded ban with a size of 305 bp. as a backcross marker revealed high
Repetitive sequenced-based PCR using of the progenies to the recurrent n
mterobacterial repetitive intergenic consensus parents. This data could be used in the
ERIC), repetitive extragenic palentdromic (REP) of the progenies that have a higher sir
and BOX primers were employed to assess the the recurrent parent together with sek
genetic diversity of the different isolates. Results the resistance genes present.
,howed that isolates that give identical banding
)attems in ERIC primers also showed identical Interaction of Vesicular-Arl
)attems with BOX primer. Definite pattems Myoorrhizal Fungi and Melc
inking fingerprint types to geographic areas of graminicola in Onion (Allum Sepa
solates was not evident. Gergon (PhilRice), MB Brown, A kd
(BIOTECH, UPLB) and SA Miller (USA
lacterlal Blight Resistance Gene Pyramids
n Maintainer Lines of Rice (Oryzae Sativa L) The interaction between \
hybrids. LM Briones (LSU), ED Redona Arbuscular mycorrhizal (VAM) fungi a
PhilRice), B. Porter, F White (Kansas State knot nematode M. graminicola was s
University, Kansas, USA), MP Natural (UPLB), the greenhouse using two onion
:M Vera Cruz and H Leung (IRRI) Yellow Granex and Red Creole.
experiment used P-deficient soil withoi
Wvhrid ri rm hmariinn in tho Dhilinninae fartili ar whilm in tha Athar th. eail uuae

sterile soil and in soil infested with M.
Meloidogyne graminicola significantly
retarted the growth of onion in the absence of
VAM fungi. The growth of VAM inoculated-pants
in P-deficient soil significantly increases
although bulbs were not produced. Yellow
Granex inoculated with Gigaspora sp. and a
mixture of three VAM fungi were significantly
taller than those plants inoculated with Glomuse
spp. Compared with uninoculated plants, the
bulb weight and diameter of Yellow Granex
inoculated with mixture of the three VAM fungi
increased by 54% and 24% in fertilized soil
without nematode. Greater increase in bulb
weight (262%) and diameter (96.4) was obtained
in nematode-infested soil indicating that the
mixture of three VAM fungi increased the
tolerance of Yellow Granex to M. graminicola.
Bulb weight and diameter of Red Creole
increased 23% and 13%, respectively, when
inoculated with G. mossae only in soil without
nematode. None of the VAM fungi used in this
study reduced symptoms of root knot disease in
onion as indicated by percentage of galled roots.

Leafspot of Sanseviera Caused by Fusarium
sp. NG Tangonan and JA Pecho (USM)

Leafspot disease Sanseviera sp (snake
plant) caused by Fusarium sp. is hereby
reported for the first time. Symptom was
characterized by browning of the upper portion
of the plant. Lesions enlarge forming bigger
botches and become water-soaked. The fungus
grew well in potato sucrose agar and mycelial
growth characteristically creamy white to
yellowish in color. Conidia measured 4.25 x 43.5
u with 3 to septations. Pathogenicity test showed
symptom developed in one to two weeks time.
Fungicidal test revealed that captain,
hexaconazole and cupric hydroxide controlled
Fusarium leafspot of Sanseviera both in vitro
and in vivo.

Transmission of Biochemical
characterization of Leifsonia xyll subsp. xyll
(Davis et al.) Evtushenko et al. 2000 Casing
Ratoon Stunting Disease of Sugarcane
(Saccharum officinarum L.) EM dela Cruz
(ISU) and MP Natural (UPLB)

After numerous attempts the causal
agent of the ratoon stunting disease (RSD) of
sugarcane was successfully isolated from three
Philippine sugarcane cultivars, namely Phil
8013, Phil 6553 and Phil 8583. The RSD
bacterium was isolated using the sugarcane
medium developed by Davis in 1980 with some
modifications. Isolations were successful from
sap extracts that were positively assayed for
RSD using dot-blot immunoassay, phase
contrast microscopy and polymerase chain
reaction (PCR). The three isolates (#8013,
#6553 and #8583) were virulent to the
susceptible sugarcane cultivars Phil 8013. Early
symptoms of internal salmon-pink discoloration
in immature nodes below the merismatic area
were observed in young shoots (7 wk old) of
inoculated sugarcane plants.
Sap extraction was made easier and
simpler with the use of positive sap expression
by pliers. Passing the sap through 0.45 um
Millipore filter nitrocellulosee membrane)
significantly increased the number of positive
isolations. Bacterial sap contaminants were
larger than L xyli subsp. xyli.
The isolates were non-motile, did not
produce spores, non-acid fast and Gram positive
becoming Gram variable on old cells. There
were aerobic and irregular shaped rods with
club-shaped and y-cell formulations typical of
the coryneform group. Cells measured 0.96 to
84 um by 0.19 to 0.29 um. Growth of the isolates
in modified sugarcane (M-SC) medium was very
slow. Colonies were evident only after 7 to 10
days incubation at 28 C. Full colony
development required 2 to 3 weeks and reached
diameters of 0.2 to 0.3 mm. Colonies were white
which turned off-white with age. All biochemical
characteristics of the three sugarcane isolates
were comparable to previous reports of the
corresponding pathogen.
In plant inoculations, the bacterium was
recovered in napier, corn and sorghum 6 wk
after inoculation by means of dot-blot
immunoassay and phase contrast microscopy.
However, no visible RSD symptoms were
observed from these experimentally infected
On the basis of morphological, cultural,
biochemical and pathological properties of the
three isolates, the RSD of sugarcane was
identified as Leifsonia xyli subsp. xyli (Davis et
al.) Evtushenko et al. 2000.

IFi'mir~e,.e I 139mw \1

ion did not develop symptoms. Results obtained during two
leapple cultivar "Smooth seasons (A and B) indicated that the f
nsidered very susceptible while causes leaf blight as well as stalk and
msistant. Some members of the cor caused crop losses as high 4
family like Cryptanthus regardless of the amount of inoculur
%uzmania linguata, Ananas 2x108, 3x108, and 4x108 conidia/n
ecmea sp. were infected when inoculation was made in ear and in col
A .*M A L L A _A, ..: ...I A.. ... .. . A I- A I I .LL I---. -m -

R ani R "A 1oA~ with tha hinhaef innrial

spectively. Prefecture is due to the fact that 58.
Stalk rot occurred only in stalk-inoculated cultivated area is planted with th
ints in both seasons. variety Koshihikari. This variety has
complete resistance gene, which
stribution of Pathogenic Races of the Rice attacked by most of the bla
ast Fungus in Northern Japan. FA delay Furthermore, 6.11% of its cultivate
nfa (PhilRice), K. Zenbayashi and S Kofzumd planted with Pia varieties: 0.24% foi
ARC for Tohoku Region, Akita Prefecture 25.29% for Pii; 5.82 for Pia, pii and 1.
pan) It is the again proven that difl
distribution of pathogenic races of F
There were 291 rice blast isolates tested greatly influenced by cultivated rice vi
13 Japanese differential varieties in year given area.
101. The most common pathogenic race
stained was 007.0, which was found in all Spatial Distribution and
efectures of the Tohoku Region but not in Development of Rice Pests In an
>kkaido Region. The frequency of occurrence Area. US Duque, JJ Tagubbse,
race 007.0 was 80.48% thus, the most EH Bay-an and ER Tiongco (PhilR
evalent race in all seven prefectures in
irthem Japan with 100% occurrence in Miyagi, Five cropping season data on
cita and Yamagata Prefectures. distribution and temporal develop
Pathogenic race of Pyricularia grisea in tungro disease ad its vector
okkaido Region was only 037.1. Aomori and virescens and the local insect pest
ate Prefectures had two races each, the 007.0 bug, Scotinophara coartata in an ern
d037.1; and the 007.0 and 017.3, in Northern Cotabato provided
spectively. Miyagi, Akita and Yamagata information on the mechanism gov
refectures had one race, the 007.0. Fukushima occurrences and spread and its m
refecture had the highest number of races (9), using host plant resistance.
which included the 001.0, 003.0, 005.0, 007.0,
)7.2, 013.1, 017.1, 037.1 and 103. Controlling Leaf Blight of Durlan I
Based on Gleason and Shannon Rhizoctonle solani. NG Tangona
dexes, Fukushima Prefecture had the highest Cuambot (USM)
mnetic diversity as compared to all other
efectures in northern Japan in year 2001. Tuba (Croton tiglium) plal
omori and Iwate Prefectures had slight genetic kamantigue (Impatiens balsamina) se
versity since two races were obtained, while in and Trichoderma sp. were found E
okkaido, Miyagi, Akita and Yamagata therapeutic control against leaf blight
refectures had 0.000 genetic diversity since R. Solani of eight year-old durian t
ily one race was found for all the isolates field. Their effects were compare

refecture had slight similarity in ra
imposition to Fukushima and Aor
refectures approaching the 1.0 valid
ikushima having none of the 10 pathog
ces obtained for all isolates in all prefect
Closely related to all the prefectures. All
her prefectures had most 0.0 values, wl
eans that racial composition among them t
sry high similarities. Miyagi, Akita and

i Fields Trial of Fungicides for the C
White Root Rot Disease of Rut
S Tangonan and VM Escopalao (USM)
Fungicides found effective age
i root rot disease of rubber ca
a Rigidoporus lignosus Imazeki in
screenhouse trials were further
identified hot spots in Matalam and Kid

lazole, difenoconazole, chlorothalonil,
ridemorph applied as eradicative
intly reduced disease severity in 8- and
old rubber trees for six months at one-
interval application. Generally, treated
showed complete recovery and
iment of fungal rhizomorphs of R.
s was inhibited.

Ides for the Control of Damping-Off in
NG Tangonan and AP Ruano Jr.

Damping-off was the most prevalent
i that attack seedlings in citrus nurseries
ARC. The disease was caused by either
onia solani, Sclerotium rolfsii or
im sp. Symptoms were characterized by
ig of leaves, girdling of the stem,
ration of vascular tissues, rotting of the
and wilting. Whitish to brownish mycelial
; of Fusarium sp., and dark brown
al bodies of R. solani and S. rolfsii were
nt at the base of the affected seedlings
enicity tests showed characteristics
ms developed 10 to 15 days after
Methyl DL-N chlorothalonil, captain,
yl, and maneb were effective against R.
On the other hand, methyl DL-N,
zeb, chlorothalonil, and captain were
e against S. rolfsii. Meanwhile,
halonil, methyl thiophanate, benomyl,
- AL, and mancozeb were effective
: Fusarium sp.

ice and Control of Black Stripe
;e of Rubber in Mindanao. NG
nan and CO Gonzalez (USM)

Surveys of rubber-growing areas in
tao were conducted in the provinces of
lani, Cotabato, Agusan del Sur, and
1 to determine the incidence of black stripe
I by Phytophthora palmivora Butler, a
I panel disease of rubber [Hevea
insi (Muell.) Arg.] These were done during
iy periods from May to December 2001. A
plantation in Matalam, Cotabato has the
t percentage incidence and severity
in of 100% while; Bayugan and Esperanza

lasilan had the lowest incidence at 10%.
Meanwhile, fungicides that she
efficacy were metalaxyl, oxadixyl, enomyl,
iancozeb. Significant curative control ovei
disease was observed for three months c
monthly applications. Treatment mixed
ticker (Hoestick) were applied by brush
method at 5 ml per tree. The rubber trees

field Evaluation of the Performance of B
;00 SC (Acibenzolar-S-Methyl) Against Nt
diseasess of Mango. GA Peratta (N(
JPLB), NT Saavedra, RC Suiza and OS i
Syngenta Phil., Inc)

A study was conducted to evaluate
performance of different rates of Boost 50(
acibenzolar-s-methyl) against major ft
liseases of mango under field conditions. B
>n the results of the experiment, all fung
treatments effectively reduced anthrac
Colletotrichum gloeosporoides) and sterr
ot (Lasiodiplodia theobromae).
Boost 500 SC at 2.5 and 5.00 g ai/'
20o exhibited excellent activity in reducing
severity of anthracnose on leaves, paniclei
lowers. At these rates, efficacy of the pr
vas comparable to the standard fungil
Score 250 SC (12.5 g ai/100 li H20) and Be
50 WP (125 g ai/100 li H2o) but performed t
han Mancozeb 80 WP (120 g ai/100 li H2o).
Boost 500 SC at higher rates
performedd better than Mancozeb 80 W
educing lesion development due to
anthracnose and stem-end rot and pro'
comparable efficacy with the other stand
Boost 500 SC at 5.00 g ai/100 li H2o pro'
he highest percent control of fruit anthrac
and stem-end rot with 95.31% and 92
control respectively.
On yield and yield components, I
500 SC at 2.50 and 5.00 g ai/100 li H2o
higher fruit yield on mango comparab
standard fungicides. The increase in fruit
nay be attributed to the excellent activity (
:est chemicals against C. gloeosporoide
eaves, panicles, flowers and fruits.
Based on the results of this study, I
SC at 2.5-5.00 g ai/100 li H2o is t
recommended against anthracnose on leave

duct performance is comparable to tt
idards and, at higher rates, performed bett
1 the standard Mancozeb 80 WP.
The tank mix combination of Boost 5(
(2.5 g ai/100 li H20) + Score 250 SC (12.5
00 li H2o) can be further tested a
pared to other combination designed 1
ngo anthracnose and stem-end Tot Init
uits showed the schedule application ai
ibination produced good quality fruits 1
ort and further testing can confirm su

knilation of Strains Bacillus subti
423-R and Pseudomonas florescens Pi
Associated with Healthy and Shea
oht Rice Plants. XM L and TWMew (IRRj

Pseudomonas fluorescens strains Pf7-
I Bacillus subtilis strain B 5423 effective
$press rice sheath blight both in greenhou
I in field, both were thought to be potent
logical control agents. The avera
>ulation sizes of strain Pf7-14, a natu
distant strain to nalidixic acid, and stn
4213-R, a spontaneous rifampicin-resisti
tant strain of B5423, to colonize on ri
ves and stems were monitored unc
henhouse condition. The results showed tl
colonization of both strains on leaves
ms were positively correlated with bactei
icentration when used when both we
>lied at rice maximum tiller stage. That of P
on leaves was higher than that of B5423
thermore, Pf7-14 survived longer on leave
n B5423-R when both were applied at I
ne concentrations. That of Pf7-14 on steel
isistently declined with time regardless
plied concentrations. In contrast, that
423-R dropped with time when lo
icentration (4.0 x 107 cfu/ml or less)
plied, whereas the average population si
nained constant or increased slightly fn
ky- to yellow-ripe stages after higl
icentrations of the bacterium (2 X108 cfu
more) was applied. The difference of the t
gains to colonize on healthy and disease
eath blight lesion) on rice stems depended
percentage of lesion area accounted
Tpled total stems area. When the percent
)elow 8%, the difference was not obvious.

Pf7-14 population size on aiseasea st
about 6 times lower than that on health
at 1 day after its application, and
diseased stems was about 2 times lo
that on healthy stems at 14 days
application. The difference showed de
trend with time. While that of B542:
about 2 times lower on diseased stems
on healthy stems at 1 day after its ap
thereafter, that of B5423-R on disease
constantly increased as compared witt
healthy stems, and it was 6 times h
diseased stems than on healthy sten
days after its application. At lesior
segments (with 70-90% lesion an
average population sizes of strain Pf7
3-10 times higher than that on health
segments at 1 to 7 days after
application. The results also demonstr
there existed intense competition
introduced biological agents and native
on sheath blight lesion stems or leaves.

Screening Corn Breeding Lin
Resistance to Philippine Corn
Mildew. NG Tangonan and MG

Promising inbred lines, open-j
varieties, and hybrids of corn com
CIMMYT and USM were screened to
select, and develop corn varieties re:
Philippine corn downy mildew. Out of
entries/lines tested, 746 were USM en
1, 783 came from CIMMYT. It was not
471 entries/lines or 58.16% showed (
resistance to the infection based
reactions to the downy mildew disease
showing intermediate reaction (459or
and susceptible (608 or 24.04%) respo
also noted in the field.

Preliminary Screening of Cardca pap
quercHfolH Interspeciic Hybr
Resistance to Papaya Ringspot VI
Magdalita, LD Valencia, AG C Sajis
Vllegas (IPB, UPLB)

A preliminary screening for resi
papaya ringspot virus involving Carica
C. quercifolia and interspecific hybrids (

_ __ ____ _

species was conducted. Plants were manually
inoculated with papaya ringspot virus (PRSV) in
the glasshouse and the reaction assessed 30
days later by symptomatology and by a plate-
trapped antigen-enzyme linked immunosorbent
assay (PTA-ELISA). AH interspecific hybrids and
C. quercifolia plants did not show PRSV
symptoms while C. papaya plants were positive
for PRSV in PTA-ELISA tests. Further screening
of the interspecific hybrids using back-
inoculation tests and exposure to heavy PRSV
inoculum in the field will be pursued.
Implications of the results in breeding for PRSV
resistance will be discussed.

Resistance of Tomato to Late Blight and
Bacterial Wilt NL Opina and JO Narciso (IPB,

Tomato advanced lines, commercial and
farmer's varieties were evaluated for resistance
to late blight and bacterial wilt in the field.
Evaluation for late blight resistance was done I
Benguet and Bukidnon while bacterial wilt
screening was done in Laguna, Pangasinan and
Bukidnon. Confirmatory tests of Promising
varieties against bacterial wilt under field
condition were made in the greenhouse using
virulent strains of Ralstonia solanacearum.
The results showed that none of the
tomato varieties evaluated against late blight
was resistant in both Benguet and Bukidnon
provinces. The disease severity range from 90
to 100% 2 months after transplanting. Marked
differences in the incidence of bacterial wilt was
observed between varieties of tomato. In
Dalwangan, Bukidnon tomato entry Shalom 2
developed at IPB had the lowest bacterial wilt
infection followed by Bukidnon F1 varieties
Hybrid 301, Hybrid 13 and Hybrid 10 with 1, 3, 4,
and 4.5% infection, respectively. In Majayjay,
Laguna bacterial wilt incidence ranged from 56
to 93%. BRC1 variety had the lowest bacterial
wilt infection at the end of the season followed
by EW 01 with 56 and 65.2% infection,
respectively. Likewise EW 01 had the lowest
bacterial wilt infection in Tayug, Pangasinan. In
College, Laguna the farmer's varieties BRC1,
Tinagbak, Del Monte and Pinusyo had higher
bacterial wilt infection of 43-53.3% compared to
IPB advanced lines F1 6174, XTH 61100, Tm
95-12, XTH6158 and Tm 95-16 with 65 to 78.8%
survival at 60 DAT.

A total of 23 tomato commercial varieties
and advanced lines were screened for
resistance to 5 strains of RI solaaceanm under
greenhouse conditions. The farer's variety
Tinagbak in Liliw, Laguna was rated resistant to
T151, the Bukidnon Varieties 1403 and BRCI,
IPB developed varieties P001, Shalom 1, XTH
6158, XTH 6193 and Tm 95-12 were rated
moderately resistant to T151 but moderately
susceptible or susceptible to the other strains. R.
solanacearum strain from Majayjay (T668) was
the most virulent followed by Liliw (T625),
Bukidnon (Tm22), Pangasinan (T623) and
Laguna (T151) Most of the tomato varieties/ines
survived when inoculated with Majayjay strain'of
R. solanacearum.


Management of Soil-Borne Dhiease In Rice
Vegetable Systems. RT Alberf (CLSU),
MaSV Duca, SE Santago (PhiRice), NL
Opine, LE Padua (UPLB) and SA Miler (Ohio
State University, Ohio, USA)

Nueva Ecija is the largest rice producing
province of the Philippines and also the largest
producer of onion n the country both for export
and domestic use. It also grows other
vegetables like eggplant in commercial
quantities for domestic consumption.
Like other economically important crops,
these vegetables are not free from disease
problems especially those that are caused by
soil-bore pathogens. To date there are no
known effective methods of managing these
disease under field condition except for the use
of resistant varieties. Because of the
seriousness of the problem, new approaches
may be developed by exploring the use of
biological control agents, genetic resistance and
cultural management that can significantly
reduce the incidence and severity of the
diseases caused by the soil-borne pathogens.
Among the 14 cultivars tested for
resistance, incidence of pink root was low in
Niagara, Condor, Robins Yellow and Red Pinoy.
Bacterial isolate Bacillus sp. (LED 118) was
found to be potential bacterial antagonist against
tree species of Fusarium, Sclerotium rolfsii and
Rhizoctonia solani. It was most effective if
applied as protective coating on the root surface.
Burning rice hull (Appx. 6 inches thick) can

old inoculum may suggest

oma terrestris in rotation with onii
nificantly reduce disease pressure resulting
r incidence and severity of pink root infectic
cterial wilt incidence was reduced in eggplE
tivars EG 203, Jackpot, DLP and graft
nt (EG203+Jackpot).

chanism of Resistance of Tomato Agair
bacco Mosaic Virus Using Protoplasts. L
lores, TO Dizon and AL Alcachupas (IF

The mechanism of resistance to tobac
)saic virus (TMV) of two resistant entries, Ai
9 and TMC 106, was elucidated usi
)toplasts. These entries exhibit
nptomless reaction upon TMV inoculatic
like the susceptible varieties, Marikit and I
-1, which showed severe mosaic symptol
)re protoplasts were obtained using youn.
lives and leaf sections than older and whi
lives. The isolated protoplasts of bi
sceptible varieties showed positive react
:h very intense yellow color in ELISA test. T
plied a high virus concentration on 1
>toplast and that the virus may have rapi
iltiplied and spread from cell to cell within 1
if tissues. In the resistant entries, protopla
Acc. 549 gave slight yellow color reaction
ntrast with the protoplasts of TMC 106, wh
sided a negative colorless reaction in the El
In infectivity assay, TMV fr
sceptible varieties (Marikit and VC 11
luced higher number of local lesion
cotiana glutinosa ranging from 7 to 8.5
.ek post inoculation and more those 15 lesic
:er three weeks. The number of lesions co
irdly be counted since the lesions coales(
ter 3 weeks. In the resistant entries, TMV
;c. 549 elicited only 2.5 lesions I the first w<
id 0 lesion in the succeeding 2 to 4 weeks
a other resistant entry (TMC 106), the vi
J not produce any lesion to the local les
>st. Such results suggest that TMV was abl(
iter Acc. 549 only for a certain period of ti
ne week) but was not able to multiply
read from cell to cell within the plant. "
'us particles were localized within the sr
af area as evidence by necrotic local lesior
alutinosa. Non-formation of lesions fro two

the virus was not able to enter the plant
Marikit and VC 11-1, TMV was able t
and to progress in the plant.
Results of ELISA test for protop
infectivity assay confirmed the presence
in susceptible plans and the resistance
Acc. 549 and TMC 106 to the virus.

Management of Clubroot in (
(Plasmodiophora brassicae Wor.]
Microbial Antagonists, Lime
Pentachloronitrobenzene. LM Villan
Tad-awan and AO Fagcayang (BSU)

Clubroot caused by Plasmc
brassicae is considered the most
disease of crucifers worldwide. Three I
microbial antagonists, namely Flavol
sp., Pseudomonas sp. and Paecilorr
applied alone and in combination witt
sub-lethal dose of Pentachloronitn
(PCNB) were evaluated to determ
efficacy against the disease and con!
assess their effects on cabbage yield.
The different treatments
significantly affect the final soil pH and'
weight. However, significant redu
clubroot infection was noted. The mosi
treatments were lime + Flavobacteri
PCNB and lime + Pseudomonas sp.
With 49.29% disease reduction. The
comparable to lime + Paecilomyces sp.
Slime alone, Paecilomyces sp. alone w
41.58, 40.57, 38.13 and 31.44% i
respectively. On the other hand,
Infection of plants treated with Flavoi
sp. alone was comparable to the
I control.
I Effective control of the disease
F in substantial increase in crop yield. Tt
percentage yield increase was record
I plants applied with lime + Flavobacted
* PCNB, However, it is comparable
I treated with the combination
Pseudomonas sp. and PCNB,
i Paecilomyces sp +PCNB, Paecilorr
r alone, lime alone and Pseudomonas
i with 138.89, 125.00, 120.83, 120.83,
I and 109.72%, respectively. Plants ap
1 Flavobacterium sp. alone gave signifies

&I rmnmnorad tn thi nthor f

ilIj 111 191 mLI l 4 I t l UW U cIL WU pLt .U I Ujn uI.

ment of XA-Gene Pyramid Rice Lines
-able Resistance to Bacterial Bight J
MVReveche, IP Otis, LM Bornes, SE
CM Millena, ER Angeles, K Webb, JE
nd CM Vera Cruz (IRRI, Leyte State
y and Kansas State University, Kansas,

acterial blight (BB) of rice caused by
onas oryzae pv. oryzae (Xoo) is one of
>r diseases of rice worldwide and it
substantial damage on rice yields.
n of host-plant resistance in reducing
ase already proven effective and is
.ly used for reducing damage due to
blight. An effective resistant gene has
able after its deployment for a long time
large area, this is essential to attain a
ble disease management for the
At present, there are 28 known BB
a genes designated Xa-genes. Only a
lese genes have been actively used in
genes tagged with molecular markers
)n pyramided into IR 24 as a resistance
n breeding program and also an
mntal population for studying pathogen
)n in nature. However, none of the
lines contain Xa7, a resistance gene
i to provide durable resistance in rice
i a 6-year study in farmers' fields. The
ie imposed a fitness penalty on Xoo
the corresponding a virulence gene,

cross between IRBB7 (carrying Xa7
id IRBB60 (carrying Xa4, xa5, xa13 and
as made to develop pyramids of Xa7 in
combinations with Xa4, xa5, xa13 and
ackcrossing and progeny selection was
i the presence of the molecular markers
the resistance genes. The presence of
:e genes was confirmed at each
ss generation. Lines containing the
gene combinations were selected and
d until all genes are in homozygous
i. Lines with different gene combinations
luated at the F6 generation against 10
:es. Reaction of the Xa7 pyramids
shorter lesions than the NILs and
bible with IRBB60 carrying four genes for
stance. Incorporation of Xa-7 and other

,V S III II* lIs IIIIU VI II Y U I si t a| I.lml
id IRRI's new plant type (NPT) from trop
ponica. Currently the pyramid lines carry
a4, xa5, xa13, and Xa21 in var
>mbinations are also grown in farmers' field;
)ntinue the study of pathogen adaptation
ness changes in the pathogen population.

ianthovirus RNAI-Like Genome Found
rassy Stunt Virus-Infected Rice Plants.
iranda (IRRI), R Aliyari, and Y Shin
University of Tokyo, Tokyo, Japan)

A genome related to Dianthovirus RN
;e (DRIL RNA, 4486 nucleotides in length)
und in a random cDNA library prepared
NA extracts from rice grassy' stunt vi
tGSV) ribonucleoprotein fractions from sucr
mnsity gradient. DRIL RNA has characters
>mmon to Dianthovirus RNA 1 such as
esence of GGAUUUUUAG potential sh
eptanucleotide at the end of the 5' proxi
RF, which encodes 1 35-kDa protein, follow
f 77 nucleotide sequence capable of forming
em-loop structure for an efficient 0 1 fra
lift to express the downstream region in a
)a putative replicase protein, (2) presence
early identical 17 nucleotide sequences in
terminal region and in a region upstream ol
RF encoding a 28-kDa, putative capsid pro
,P),and (3) near identity of the 3'-terminal
icleotides to those of Dianthovirus RN
/estem blot analysis using primers specific
RIL RNA of fractions after sucrose den
adient centrifugation of RGSV nucleoprotE
dicated that DRIL RNA is associated with
3-kDa putative CP but not with the 36-1

preliminary Evaluation of Multilines v
different Genes for Bacterial Leaf Blighl
Ice. RE Tablen, MC Abalos, MP Ferma
nd EBR Tadley (PhilRice)

several genes for bacterial leaf blight (BLB)
3w available and being pyramided in seven
snetic backgrounds like IR64 and in he proc
F the development, line with single gene
sne combinations can be generated. Th
ies are typical isolines that can be tappe(
ie development f multilines. Through As
ice Biotechnology Network (ARBN), elite lin

change of lines was initiated. Two lines fr<
lonesia, Bio 1 and Bio 2 with IR
ckground containing xa-5 and xi
spectively and 3 lines also with IR
ckground developed by PhilRice wm
aluated together with mixture of these line, J
-19-3-3 had he highest yield of 4.62 t
owed by AR 32-19-3-4 with 4.53 t/ha, be
nificantly higher than the IR 64 and P!
28. The check varieties were sever
ected with BLB thus producing the least yie
mbinations of different lines (1:1 ratio) wt
luded to check the disease reaction usi
iltilines. Initial data showed different
action to BLB. Pure stand of IR 64 and PI
.28 were severely affected but addition
other resistant lie improved the ovei
instancee of the new population.

lelism Test of Blast Resistance Genes
RI Rice Varieties. LA Ebron, Y Fukuta,
be, H Kato, MJT Yanoria, H Tsunemat
i Khush and M Yokoo (IRRI; NICS, Tsuku
pan; MAES, Miyazaki Prefecture, Jap,
4RDA, Ivory Coast; University of Tsukui

Allelism test to confirm the presence
: blast resistance genes Pib, Pik-s Pi
*, Pita and Pi20 were carried out in ei!
te IRRI rice varieties. F2 and Fa populatic
rived from crosses between IRRI varieties a
ferential lines were inoculated with bl
plates having known virulence genotypes.

Tsuyuake, and Kanto 15 were used t
allelism of Piz-t. Pib and Pik*, res
Yoshiromohi and near-isogenic lines,
Piz-t were confirmed in IR34 while Pi2
were confirmed in IR24. IR36 was cor
have Pib, Pik-s, Piz-t and Pita. Both
IR70 have been confirmed to have Pik1
Pik* was confirmed in IT74 and PSBI
Pib, Pik-s and Piz-t were confirmed in II

Antibacterial and Molluscicidal Pro;
Piper betle Linn. L Lirio (BSU), J Pi
M Hofter (University of Ghent, Ghent, I

Antibacterial in vitro bioassay
the presence of bioactive compour
chloroform fraction of Piper betle les
The minimum inhibitory concentrations
60, 125, and 60 ug/ml for Agro
tumefaciens, Erwinia amylovora, E. c
pv carotovora and Xanthomonas cam,
campestris, respectively. Direct bioaul
on LTC confirmed the presence of one
compound identified s hydroxyhavicc
MS and NMR spectroscopy analyse!
tests further confirmed the antibacteri
of the leaf extract using the chosen tes
X.campestris pv campestris, he causa
the black rot of cabbage. The same le
also showed molluscicidal activity aga
and snails that ate common cabbage
vegetables being grown in Benguet.


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