Current Status of Research on Plant pathogens and Biological Pesticides

1

Suraj Baidya, Senior Scientist (S-4)

PLANT PATHOLOGY DIVISION

NEPAL AGRICULTURAL RESEARCH COUNCIL (NARC)

KHUMALTAR, LALITPUR

Plant specific diseases

1. Information of practical value generated

2. Appropriate research materials and methods developed and made available to concerned stakeholders

3. Effective and sustainable disease management technologies developed

4. Mandated services delivered appropriately

5. Institutional and individual capacity enhanced

6. Generated technologies fed into uptake pathways

Objectives

1. Information of practical value generated

• Survey of plant diseases

• Isolation, identification, characterization, and preservation of pathogens an

bio-control agents

• Host range and epidemiological studies of priority diseases

2. Appropriate research materials and methods developed and made available to

concerned stakeholders.

• Screening materials for host resistance and efficacy of agro chemicals against priority

diseases

• Techniques on inoculum multiplication, inoculation, screening methods and disease

assessment

3. Effective and sustainable disease management technologies developed

• Monitoring of priority diseases

• Conduct on-station research on fungal, bacterial, viral and nematological diseases of

major commodities

• Conduct on-farm research to validate the technologies

4. Mandated services delivered appropriately

• Diagnostic services

• Advisory services

• Information and visitors services

5. Institutional and individual capacity enhanced

• Upgrading of laboratory facilities and equipment

• Specialized training at national and international levels

• Exchange visits (National/International)

• Supervise graduate and post graduate students in collaboration with academic

institutions

6. Generated technologies fed into uptake pathways

• Transfer of technologies to stakeholders

• Training/ Publications

• Information dissemination through different electronic media

SCOPE ON PLANT PATHOLOGICAL RESEARCH

S.

N.

Causes Effects Outcomes

1. Open border – Informer Trade

/ Former Trade

Chances of Introduce of

new pest/ QPs

Out brake of new

diseases

2. Introducing of high yielding

cultivars/genotypes - Hybrid

Susceptible for minor

pests become major

Out break of new

diseases

3. Off-season and new crops

cultivation

Susceptible/host for

minor pests

Outbreak of new

pathogens/ diseases

4. High biodiversity Congenial environment

due to wide host range

Establishment of

Pests

5. Climate / Climate change Spread of pests Establishment of

Pests

6. Cultivation practices -

(plastic tunnel)

Adverse effect to

beneficial organisms

Establishment of Pest

7. Injudicious use of pesticides

and fertilizer

Toxicity on plant and

soil, adverse effect on

environment, Resistant

in pest

Reduce the

production and

Productivity

Identification of Pathogens

Improvement of Plant health through disease management in cropping

system

Pathogen free products/consignments

Detection of Pathogens

Improvement of Plant health through detection of associated

pathogens

Entry of Pathogen free products/consignments

Role of Pathological Research on trade

ExportImport

Survey and surveillance of pest and update national pest database Pest Risk Analysis (PRA) Preservation and maintenance of pathogens (Repository centre)

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Nu

mb

er

of

sam

ple

s (N

)

Fiscal Year (BS)

Total Disease entries Fungal disease

Bacterial disease Viral disease

Nematode disease Others/nutrient def./insect damage/unidentified

Frequency of plant disease samples diagnosed in different years in Plant Pathology Division lab

Crop Disease Pathogen

Rice BlastBacterial leaf blight (BLB)Foot RotFalse smutUdbatta (Incense rod disease)

Pyricularia oryzaeXanthomonas oryzae pv oryzaeFusarium moniliforme/proliferatumUstilaginoidea virensEphelis oryzae

Maize Gray leaf spot (GLS):Northern leaf blight (NLB) Stalk rotBanded leaf and sheath blight

Cercospora zeae maydisExserohilum turcicumFusarium verticilloidesRhizoctonia solani

Wheat RustYellow rust/Leaf rust/Stem rustKarnal BuntFoliar blight

Puccinia striiformis , P. triticina,P.graminisTilletia indicaBipolaris sorokiniana/Drechslera tritici-repentis

Lentil Stemphyllium blightWilt/Root rot complex

Stemphyllium botryosumFusarium oxysporum/ Fusarium solani

Chickpea Botrytis gray moldWilt/Root rot complex

Botrytis cinereaFusarium oxysporum/ Fusarium solani

Common diseases in various crops

Crop Disease Pathogen

Crucifers ClubrootRhizoctonia diseaseBlack rotBacterial leaf spot of broad leaf mustard

Plasmodiophora brassicaeRhizoctonia solaniXanthomonas campestris pv. campestrisPseudomonas syringae pv. maculicola

Solanaceouscrops(Tomato/ Potato / Eggplant)

Late blightCommon scab, powdery scabBacterial wiltViral disease complex

Root Knot Nematode Bacterial stem rot of tomato

Phytophthora infestansStreptomyces scabies, Spongospora subterraneaRalstonia solanacearumTYLCV (Tomato Yellow Leaf Curl Virus, ToMV(Tomato Mosaic Virus), CMV (Cucumber Mosaic Virus), PepMV(Pepino Mosaic Virus)Meloidogyne sppErwinia carotovora subsp. carotovora

Cucurbits Viral disease complex

Downy mildewGummy stem blight

CMV (Cucumber Mosaic Virus), ZYMV (Zucchini Yellow Mosaic Virus), CGMMV (Cucumber Green Mottle Mosaic Virus), WMV (Watermelon Mosaic Virus) Pseudoperonospora cubensisDidymella bryoniae

Pepper Phytophthora blightViral disease complex

Phytophthora capsiciCMV (Cucumber Mosaic Virus), PVMV (Pepper Veinal Mottle Virus), TLCV (Tomato Leaf Curl Virus)

Crop Disease Pathogen

Citrus Canker Xanthomonas axonopodis pv.citri

Banana Sigatoka leaf spotPanama wiltHeart rot

Mycosphaerella musicolaFusarium oxysporum fsp. cubenseFusarium moniliforme

Mango AnthracnosePowdery mildew

Colletotrichum gleosporioidesOidium magniferae

Apple Scab Venturia inaequalis

Sugarcane Red rot of sugarcane Colletotrichum falcatum

Cardamom Wilt complex/Rhizome rotLeaf blight complex/rustViral disease

Fusarium sp, Rhizoctonia sp,Pestalotia sp, Phakospora sp

Tea Blister blight Exobasidium vexans

Coffee Rustanthracnose

Hemileia vastatrixGleosporium gleosporioides

•Preservation of more than 20 isolates of fungal plant pathogens

• Cultures of plant pathogens provided to different research

stations and students for their research

Bipolaris

sorokinianaRhizoctonia

solani

Colletotrichum falcatumFusarium solani Colletotrchum

gloeosporioides

Pyricularia oryzae

NTCC (Single spore culture of plant pathogens maintained in Plant Pathology Division)

A. brasssicae from

radish

Colletotrichum falcatum from

sugarcane

Botrytis alli from garlic Pyricularia setariae from foxtail

millet

PLANT DISEASE MANAGEMENT

-Soil - nutrients-Water/moisture - Humidity-Temperature - Heat/light- Aeration - Others

Chemical methods

- Contact - Systemic Dose , number and interval

Cultural methods- Spacing - Sanitation- Date of planting - Inputs

Eco-friendly substances

- Botanicals - Biologicals

Dose, number and interval

Genetic materials- Screening - Breeding

– Tissue culture Local Exotic

Problem Identification- Biotic - Abiotic

Causal agent

- Disease cycle/epidemiology

Potential economic losses- Qualitative - Quantitative

Management

SN Bio-control agents Plant diseases

1. Trichoderma harzianum Sclerotinia sclerotiorum in cauliflower, Rhizoctonia

solani in bean wilt, ginger rot, Pythium sp.

Alternaria sp., Fusarium sp. In damping off disease

of vegetables, Root knot nematode in vegetables

2. Trichoderma viride Plasmodiophora brassicae in brassica, Rhizoctonia

solani f. sp. sasakii in BLSB of maize

3. Trichoderma harzianum (T22) Bipolaris sorokiniana in wheat, Rhizoctonia solani f.

sp. sasakii in BLSB of maize, Meloidogyne sp. in

tomato

4. Trichoderma spp. (A23) Bipolaris sorokiniana in wheat

5. Paecilomyces lilacinus Meloidogyne sp.in tomato, Plasmodiophora

brassicae in brassicas

6. Pestaloptiosis sp. Sclerotinia sclerotiorum in cauliflower

7. Pseudomonas fluorescens

Pseudomonas sp.

Meloidogyne in tomato, Plasmodiophora brassicae

in brassica

Bio-control agents used against Plant diseases

SN Botanical extract Plant diseases

1. Extract of garlic 1% Club root disease and viral disease

complex

2. Application of cow milk @ 25m/l water Viral disease complex in vegetables

3. Extract of timur (Zanthoxylum

armatum) 1%Leaf spot disease (Fungal disease)

5. Black pepper Extract 1% Leaf spot diseases (Fungal disease)

6. Extract of clove 1% Bacterial wilt, Sclerotinia sclerortiorum

7. Asparagus root 1% Alternaria leaf spot diseases,

Rhizoctonia solani

8. Tete-pati (Artemisia vulgaris) and

Ashuro (Justicia adhatoda) 10%Soil borne diseases (Rhizoctonia,

Fusarium)

9. Eucalyptus leaf extract 10% Leaf spot and foliar blight in vegetables

10 Tejpat or bay leaf (Cinnnamomum

tamala) extract 1%Rhizoctonia solani, Sclerotium rolfsii

11. Mustard cake @ 40g/ plant Root knot nematodes

Botanical extracts using against Plant diseases

Inhibition of colony growth and

sporulation by 10% leaf extract

of eucalyptus

Inhibition of Sclerotium rolfsii

>80%) by Trichoderma sp. Inhibition of Alternaria alternata

(>80%)by Trichoderma sp.

Rice blast:

Causal agent: Pyricularia oryzae

Management:

• Resistant cultivars: Khumal- 4, 6, 8, 10, 11,

Chandannath – 1, 2, Lekali -1,3 for hill.

• Parawanipur 1, Janaki, Chaite 2, Khajura 2,

Radha 4, 7, 11, Hardinath 1, Shwonna 1 and

Shukhkha 1, 2, 3, 4, 5 and 6 for Terai/plain.

• Balance fertilizer: Recommended dose of

NPK, not excess N application

• Seed treatment: Beam (Tricyclazole) 2 g/ kg of

seed

• Foliar application: Kasugamycin 3% @ 2 ml or

Beam 1 ml or Hexaconazole 2 ml per liter of

water in vegetative and panicle initiation

stage.

Sheath BlightCausal agent: Rhizoctonia solani

Management:

• Balance fertilizer: Application of

recommended NPK.

• Transplanting : Not dense planting

• Foliar application: Application of

Hinosan @ 1.5 ml or Validamycin @ 2

ml per liter of water.

Foot rot

Causal agent: Fusarium moniliforme

Management:

• Seed treatment: Application of Bavistin

(Carbendazim) @ 3 g/ kg seed

• Drenching: Application of Bavistin

(Carbendazim) @ 2 g/ liter of water

Management:

• Balance fertilizer: Use of optimal

amount of fertilizer

• Seed treatment: Application of Dithane

M-45 (Mancozeb) @ 3 g/ kg seed

• Foliar spray: Application of Dithane M-

45 (Mancozeb )@ 3 g/ liter of water

Brown leaf spot

Causal agent: Bipolaris oryzae

Management:

1. Planting of resistant genotypes such as

Manakamana-1, Manakamana-3, Manakamana-6,

Ganesh-1, Deuti and Hill Pool Pahelo. Some

Columbian and Zimbawe lines; 05 SADVI, 07

SADVI, ZM 627 and ZM 525 are also resistant to

disease.

2. Early planting and sanitation

3. Application of fungicides like Bavistin

(Carbendazim) @ 1.5 g or Dithane M-45

(Mancozeb) 2.5 g per litre of water in 7-10 days

interval.

Gray Leaf Spot of Maize

Causal agent: Cercospora zeae

Wheat rustCausal agent: Puccinia striiformis (stripe/yellow rust), P. triticina (leaf/brown rust), P. graminis (stem/black rust)

Management:

• Use resistant varieties: Stripe rust: Pasanglhamu, WK1204, Dhaulagiri, Danphe, Gautam, Tilottama

Leaf rust: BL1473, Bhrikuti, Achyut, NL971, Aditya, Gautam,

Bijaya, Gaura, Bhrikuti, Tilottama

Stem rust: Dhaulagiri, Danphe, Bijaya, Tilottama, Gaura

• Spray Propiconazole 25% EC @ 1 ml or triadimefon 25 WP @ 1 g/litre of water.

Late blight of tomatoCausal agent: Phytophthora infestans

Management

• Some CIP lines were resistant/tolerant

to disease.

• Spraying of systemic fungicide with

Metalaxyl @ 1.5 g/ l of water in 10 days

intervals or spraying of Sectin – 60 WG

( Fenamidone 10% + Mancozeb 50%)

@ 2 g/ l of water in 10 days intervals.

• Sanitation: removal of volunteer plant

and other disease plant parts.

• Spraying of fungicides with Copper

oxychloride @2 g/l or Mancozeb @2.5

g/ l of water in 7-10 days interval.

Early blight of tomatoCausal agent: Alternaria solani

Damping off of seedlingCausal agent: Rhizoctonia sp., Phytophthora sp., Pythium sp., Fusarium sp. Sclerotinia sp.

Management:

• Nursery bed treatment with Carbendazim2 g/ l of water.

• Foliar spray of chemicals with Carbendazim @ 2 g or Mancozeb 2.5 g/ l of water.

• Drainage facility

Management:

• Sanitation: Removal of disease plant parts from field

• Foliar spray of Sulphur chemicals like Karathane @ 2 ml at 7 – 10 days intervals at least 2-3 times

Powdery mildewCausal agent: Leveillula taurica sp.

T-260 Control

For the control of Phytophthora capsici

in chilli, Trichoderma isolate T-260 @

0.2% as soil drench was found to reduce

disease incidence and severity by more

than 70% as compared to control.

For the control of Rhizoctonia solani in

cauliflower, application of sectin (Mancozeb

50%+ fenamidone 10%) @ 2g/l water as soil

application before transplanting of cauliflower

seedlings was found as the most effective.

Left: control, Right: sectin

• Field trial at Luvu, Lalitpur showed that

Marpha rayo was less susceptible to clubroot

than the local variety used.

Top: Local BLM, bottom: Marpha

Management of clubroot in crucifers

• Use of agricultural lime to increase soil pH upto 7.

This should be done at least one month prior to

transplanting of seedlings.

• Use of nebjiin (Flusulphamide) as soil

incorporation @ 200-300 kg per ha was found to

reduce clubroot incidence by 61% and severity by

83% in cauliflower in field trial done at Bhaktapur.

• Screening of different genotypes of

tomato against bacterial wilt showed that

HRA 19, HRA 21, HRA 7, HRA 109, HRA

112, SSC-1 were resistant among OP

genotypes tested while F1 hybrids

(Ahmita, Manita, Platinum 701, Surya,

Dalila and Makis (Bishesh) were found

tolerant to disease.

Screening of tomato genotypes against

Ralstonia solanacearum in screenhouse

Management of bacterial wilt disease in solanaceous crops

• Use of Copper oxychloride @

0.2% as soil drench

• Grafting of tomato scion in

rootstock of wild brinjal (Solanum

sisymbrifolium)

Left: Cultural characteristics of R. solanacearum in

TZC media, Right: symptoms of bacterial wilt in

tomato

Root Knot Nematode

Causal agent: Meloidogyne sp.

Management

• Selection of seedling from nematode free nursery bed

• Destroy the infected plant part after harvesting

• Soil application of biological agent Trichoderma

harzianum

• Application of crushed yellow mustard seed 40g/

plant hole during transplanting

• Using grafted plant with wild brinjal (Solanum

sisymbriifolium)

• Soil application of Mustard cake 2kg/ m2

• Soil application of Cartap1.5 kg /500 m2

Gummy Stem Blight of CucurbitsCausal agent: Didymella bryoniae

Management:

• Sanitation:

Cleaning of weeds and solanaceous

crops.

• Thining/ trimming: remove dry and

diseased leaves

• Seed treatment:

Mancozeb or Chlorothalonil

containing chemicals @ 2 g per kg of

seed

• Foliar spray: Application of chemicals

with Mancozeb @ 2.5 g or

Chlorothalonil @ 2g per liter of water

in all part of plant in 7 – 10 days

interval for at least 2 -3 times

Lentil RustCausal agent: Uromyces fabae

Management

• Resistance lines: ILL 7164, ILL 7723 and Shital.

• Planting time: Early planting have more diseaseso planting late i.e, date of planting according todisease appearance on particular location

• Chemical application: Spraying of Dithane M-45(Mancozeb) @3 g/ l of water at 7- 10 daysinterval at least 2 times.

Lentil gray mold diseaseCausal agent: Botrytis cinerea

Management

• Spacing: Planting at row to row distance 30-40cm

• Intercropping: Intercropping with potato.

• Chemical application: Spraying of Chlorothanilcontaining chemical @2 g/ L of water at 7- 10days interval at least 2 – 3 times.

Stemphylium blightCausal agent: Stemphylium botryosum

Management

• Resistant cultivars: Shikhar, Shimal, Maheshwor,Bharati, Sagun, Khajura 2, ILL 7723.

• Spacing: Avoid dense planting i.e, row to rowdistance 30 cm at least

• Seed treatment: Bavistin (Carbendazim) 2 g/ Kgseed.

Foliar spray: Chemicals with Mancozeb @ 2.5 g orCopper oxychloride @ 2 g or Carbendazim @ 1.5 g/ lwater

Management

• Resistant cultivars: Shikhar, Shimal, Shital, Khajura 2,Sagun, Maheshwor, Bharati

• Fertilizer: Balance application of NPK.

• Biological control: Application of Trichodermaharzianum @ 500 g per ropani in soil.

• Crop rotation: with cereal crops at least 2 – 3 yrs.

Wilt diseaseCausal agent: Fusarium oxysporum

Coffee Rust

• Hemileia vastatrix

Hemileia= Having Half circle rough surface

Vastatrix = Devastating

• Uredospores are like kidney shape

MANAGEMENT

1. Quarantine: Follow the rules of internal and external

on transportation of planting materials from one place

to another.

2. Plantation of resistant genotypes such as Catimor,

Ketisic and Selection -10

3. Optimum level of shade, Wide distance of plantation

4. Sanitation

5. Application of Bordeaux mixture @ 1 % or Blitox 50

(Copper oxychloride ) @ 2 g /L for organic coffee

6. Spray Dithane M-45 @ 2.5 g or Propiconazole 25 %

EC @ 1 ml per litre of water for inorganic coffee.

Red rot of sugarcaneCausal agent: Colletotrichum falcatum

Management

• Cultural Practice: Destroy the infected plant fromthe field.

• Fungicide treatment: Treated the plantingmaterial with dipping in Carbendazim solution @1.5g/L.

• Hot water treatment: Dipping planting materialsin hot water (50ᵒC) for 30-45 mins.

Milky mushroomGanoderma cultivated in

paddy straw Training on Shiitake

mushroom cultivation

Mouth part of Plant parasitic nematode and lateral lines of body

Surface structure of wheat rust pathogen (Puccinia triticina)

SCANNING OF ELECTRON MICROSCOPE

Colony of plant bacteria Bacillus sp.

Incubation room

Screenhouse

Polyhouse

Glasshouse

Others facilities at PPD, Khumalar, Lalitpur

Glass house

Challenges

• Population growth and Flattening yield increases

• Export and Import obligation on WTO agreement

• Climate change: warming and extreme weather (Foliar blight, Rusts, Alternate

hosts, Crop var. etc)

• Rapid retiring of Senior scientists and technical personals

• Lack of incentive and motivation to scientists and technicians

Future need

• Establishment of Centre for Advance Studies for Plant Pathology

• Capacity building and Training

• Regular program on Survey and surveillance and regular update national pest data base

• Strengthen research for control of major threatening diseases of crops

• Climate resilient technology for disease control

• Strong linkage and co-ordination among Research, Extension and Education and other

stakeholders

• Use expertise of ex NARC/DOA/Universities/Others

THANK YOU