DISEASE MANAGEMENT IN ORGANIC FARMING

ARUN KUMARCentral Arid Zone Research Institute

Jodhpur-342003, India

LCD DM

A susceptible host , a virulent pathogen and favourable environment is essential

Manipulating environment to discourage pathogen is grower’s best tools to prevent or minimize disease

Interactions of temperature and moisture affect disease development

Field sanitation; Crop and Cultivar; Cultivation Practice; Crop rotation; Mixed and intercropping; Fertilization; Irrigation and seed treatments affect disease occurrence

INDIGENOUS KNOWLEDGE AND PLANT DISEASE MANAGEMENT

Traditional FungicidesTraditional Fungicides

Traditional Fungicides Disease Management

Ash Powdery mildew of cumin & mustard; white rust and downy mildew of mustard

Ash with common salt

Cuscuta of Lucerne

Ash with castor oil Damping-off of cotton

Asafoetida Collar rot of bottle gourd

CULTURAL PRACTICESCULTURAL PRACTICESMultiple cropping:

Mixture sowing (7:1:1:1) of pearl millet with legumes, sesame and cucurbits

Minimize crop losses in drought, soil crusting, pest and diseases

Fallowing for 2-years Reduce soil-borne diseases of pearl millet with legumes, sesame and cucurbits

Crop Rotation Reduces cumin wilt, DM of Isabgol, mustard-wheat rotation in Rabi & Pearl millet in Kharif

Flooding Suppression of sooty mould and insect of cotton

Restrained Irrigation Checks spread of aphids and DMs

INPUTS, LABOUR REQUIREMENT AND SUSTAINABILITY INPUTS, LABOUR REQUIREMENT AND SUSTAINABILITY OF TRADITIONAL PRACTICES FOR MANAGING OF TRADITIONAL PRACTICES FOR MANAGING

DISEASESDISEASES

Traditional practices

External inputs needed

Labour requirement

Sustainable?

Adjusting planting time

Low Low Yes

Mixture planting Low Low Yes

Crop rotation Low Low Yes

Fallowing Low High Yes

Multiple cropping

Low High Yes

Ash dusting High High Yes

Deep plowing Low High Yes

MANAGEMENT OF CHILLI DISEASES:MANAGEMENT OF CHILLI DISEASES:

• Leaf curl disease

• Die-back

•Rajasthan is the 6th largest producer in India

•Jodhpur region produces 42.7% red chilli on 20,000 ha of land

•Jodhpur district alone contributes 20% of total production of red chilli in the State

•Popular chilli cvs: Mathania Red, Mehsana, Haripur-Raipur and Mandoria

Continued..

BACKDROPBACKDROP

•Large and fleshy fruits, mild pungency and brilliant red colour with rich spicy flavour

•Susceptible to diseases like LCD and die-back or ripe fruit rot

Green Fruit Yield of chilliGreen Fruit Yield of chilli

YearYear Fruit Yield (KgFruit Yield (Kg-ha-ha))

Before 1990 600

1991 - 2004 140

SYMPTOMSSYMPTOMS•Curling of upper leaves Curling of upper leaves with shortened internodeswith shortened internodes• Severely infected plants Severely infected plants produce clusters of produce clusters of reduced sized leaves with reduced sized leaves with fewer flowers and fruitsfewer flowers and fruits•Small sized fruits are Small sized fruits are produced with deformed produced with deformed seeds seeds

LCD of chilliLCD of chilli

Small sized fruits Clusters of reduced size leaves

• Farmers extensively use a number of insecticides to protect the crop from LCD

• Use of pesticides has failed to minimize the losses.

• Causes environmental pollution, resistance in insect vectors and health hazards

EXISTING MANAGEMENT PRACTICEEXISTING MANAGEMENT PRACTICE

BIO-CONTROL AGENTSBIO-CONTROL AGENTS

•Bio-control agents have emerged as a new method of managing plant diseases.

•Different botanicals (Plant spp.), animal products and other materials such as ash, cow urine and dung, fish meal and milk etc.

•Rhizobacteria (PGPR), leaf proteins, proline and Trichoderma spp. reduce diseases in many plant species manipulating host plant's physical and biochemical properties

USE OF MILK USE OF MILK IN PLANT DISEASE IN PLANT DISEASE MANAGEMENTMANAGEMENT

Indigenous ancient tool against plant diseases

Amino acids viz. proline, isoleucein and phenyl alanine in milk induce resistance against plant diseases

Phenolic anti-microbials are also present

Potassium phosphate content strengthens host immune system against diseases

TREATMENT (T 1)Treated chilli seeds with RCM (1:1)

for 24 hrs

Dried in shade

Treated these seeds with Trichoderma viride ( @ 6g-kg seed)

Nursery soil treated with T. viride (@ 10gm2) after mixing with FYM

Seed sowing in nursery

45 DAS roots of plant saplings

were dipped in RCM (15% or 1:6) for 20 min. before transplanting

20 DAS

RCM (15%) sprayed on the transplanted plants

FARMER’S PRACTICE(T 2)

Most of these practices are chemical sprays with or without seed treatment

Chilli-root-dip treatment with RCM (1:9)

Treatment LCD Incidence (%)

Protection over FP (%)

T 1. Seed Treat. with RCM and T. viride)+ RCM root dip + nursery soil treat. of T. viride and RCM sprays on transplanted plants

  

19.4

  

48.4

T 2. Farmer’s Practice

  

37.6

  

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On-farm management of LCD

(Pooled data of 2002-04)

AVERAGE YIELD PARAMETERS OF CHILLI IN TWO AVERAGE YIELD PARAMETERS OF CHILLI IN TWO TREATMENTSTREATMENTS

Treatment* 

Plant height (cm)

Root length(cm)

No. of fruits plant-1

(g)

Fruit size(cm)

Fruit wt. plant-1

(g)

Yieldplot-1

Kg-1

  

LengthLength WidthWidth

T 1T 1 66.3 20.2 66.4 10.4 4.5 306.2 3.32#

T 2T 2 57.5 13.9 40.1 9.2 3.9 219.4 2.72

**T1T1.. Seed treatment with RCM (50% dilution with water for 24 h) and Trichoderma viride (0.6%) with soil treatment with T. viride (10g m-2 ) mixed with FYM T2. Farmer’s Practice # more than 0.5 kg ha-1 increase

ON-FARM LCD MANAGEMENT IN CHILLION-FARM LCD MANAGEMENT IN CHILLI

Treatment

Farmer’s Practice

Particulars Farmers’ Practice(T 2)

Raw Cow’s Milk + T. viride treatment (T1)

CostSeed 375.00 (1.49)* 375.00 (1.52)FYM 1990.74 (7.92) 1990.74 (8.06)Fertilizer 1226.85 (4.88) 1171.71 (4.74)Pesticides 1157.41 (4.61) 281.48 (1.14)Irrigation 14814.26 (58.97) 14880.26 (60.26)Machinery 2078.70 (8.27) 2078.70 (8.42)Labour 3481.48 (13.86) 3916.08 (15.86)Total 25124.44 (100.00) 24693.97 (100.00)

ReturnProduction (q ha-1) 110 138 (25.45)Production (Rs. ha-1) 33000 41400Unit cost of production (Rs. q-1) 228.40 178.94Net return (Rs. ha-1) 7875.56 16706.03B-C ratio 1.31 1.68

Cost and return from chilli crop ( Rs. ha –1)

*Figures within parentheses are percentages to the total

WE LOVE MILKWE LOVE MILK

Inspired farmersInspired farmers

MANAGEMENT OF PEARL MANAGEMENT OF PEARL MILLET DOWNY MILDEWMILLET DOWNY MILDEW

Downy Mildew caused by Sclerospora graminicola is a national problem

Major limiting factor of pearl millet production in all millet growing tracts

Modern interventions are not cost feasible

Tried alternative technology based on IK

Raw cow’s milk and Raw cow’s milk and Gliocladium virensGliocladium virens induced induced resistanceresistance

Tried to amalgamate indigenous and modern technology

Milk is a known abiotic inducer of resistance in susceptible plants

Pre-sowing seed treatment of RCM and G. virens with soil application of G. virens

Off- and On-farm studies provided encouraging results

Achieved protection over control (up to 72.9%)

DOWNY MILDEW CONTROL BY DOWNY MILDEW CONTROL BY GLIOCLADIUM VIRENS & GLIOCLADIUM VIRENS & RCMRCM

Pre-treatment of pearl millet seed with RCM & 0.6% fungus Soil application(10gm-2) with FYMIsolation of roots of treated plantsProvided 48% protection over FP

Certain amino acids demonstrated to act as inducers of plant resistance against biotic or abiotic stresses in many host-pathogen systems (Buzi et al., 2004)

Besides inducing resistance these amino acids also enhance growth of plants and act as osmoprotectants (Hong et al., 1999; Ramos et al., 2005)

AMINO ACIDS AND PLANT DISEASE PROTECTION

AMINO ACIDS AND PROTECTION (%) AGAINST DOWNY MILDEW

Amino acid % DM Protection

Proline* 67

Isoleucine# 57

Leucine# 55

Serine# 53

Tryptophan# 51

Methionine** 57 * Niranjan Raj et al. (2004). Phytoparasitica 32: 523-527.# Shetty et al. (2005). Proc. Global Confr., Nov. 25-29, RCA, Udaipur,p. 73. ** Sarosh et al. (2005). Plant Physiology and Biochemistry 43: 808-815.

HOW AMINO ACIDS ARE OFFERING PROTECTION ?

Amino acid-mediated induced resistance works through activation of the phenylpropanoid pathway and accumulation of phenolic compounds (Shetty et al. 2005)

Defense related enzymes comparable to the resistant cultivar are elicitated by L-methionine application through activation in chitinase, PAL, peroxidase, lipoxygenases, beta-1, 3-glucanase and chalcone synthase in pearl millet against downy mildew (Sarosh et al., 2005).

AMINO ACID CONTENT OF RAW COW’S MILK *

Amino acid In RCM

(mg-100 ml.)

Amino acid In RCM

(mg-100 ml.)

Glutamic acid 731 Tyrosine 172

Isoleucine 165 Threonine 146

Lysine 268 Methionine 86

Phenylalanine 171 Histidine 84

Hydroxyproline 330 Glycine 66

Aspartic acid 261 Tryptophan 23

Valine 202 Cystine 21

Serine 197 Arginine 18

Leucine 326 Alanine 110* Payne-Botha, S. and Bigwood, E. J. (1959). Amino-acid content of raw and heat sterilized cow’s milk British J. Nutrition 13: 385-389.

AMINO ACIDS USED AGAINST DOWNY MILDEW

•Glutamic acid

•Proline

•Isoleucine

•Lysine

•Phenylalanine

Amino acids % DMDI % Protection

L-Glutamic acid 66 31.2

L-Isoleucine 33 65.6

L- Lysine 82 14.5

L-Phenylalanine 31 67.7

L-Hydroxyproline 43 55.2

Neutral Control (DW)

96 -

Positive Control (Metalaxyl) 6 g kg-1

12 87.5

INCIDENCE OF DM IN PEARL MILLET PLANTS TREATED WITH DIFFERENT AMINO ACIDS

RCM*Treatmt.

Phenylammonialyase (PAL) activity+

Hrs. 0 3 6 12 24 36 72

T1 0.05 0.03 0.22 0.38 0.50 0.70 0.71

T2 0.08 0.22 0.36 0.53 0.69 0.85 1.10

T3 0.13 0.36 0.45 0.69 0.82 0.92 1.36

T4 0.05 0.08 0.09 0.16 0.12 0.18 0.31

T5 0.06 0.08 0.13 0.14 0.21 0.24 0.35

T6 0.03 0.11 0.16 0.17 0.17 0.20 0.22

(μmol of trans-cinnamic acid mg-1 protein h-1)

* T1-1:3, T2-1:6, T3-1:9, T4-1:12, T5- Neutral control T6- Positive control + DAS, Mysore

EFFECT OF BIOCONTROL AGENTS ON DOWNY MILDEW INCIDENCE AND PEARL MILLET GROWTH

Treatment Disease incidence

(%)

Protection over control

(%)

Root length

(cm)

Plant height

(cm)

No. of tillers

S.T.of RCM (1:1) for 18 h

12.6

(14.3)

57.4

(36.4)

10.5 75.1 12.1

S.T.of G. virens (6g kg-

1) seed

8.8

(13.0)

70.2

(42.2)

10.5 90.0 13.2

Soil treat. with G. virens (10g m-2)

12.6

(13.8)

57.4

(38.6)

10.2 92.0 14.5

Combination of above treats.

8.0

(11.6)

72.9

(48.4)

10.2 85.9 15.6

Control 29.6

(22.5)

-- 10.4 84.2 15.6

CD at 5% 8.28 2.52 18.32 8.81

EFFECT OF RCM DILUTIONS ON SEED GERMINATION AND SEEDLING VIGOUR

Of all the RCM dilutions 1:12 showed maximum percent germination followed by 1:9 and 1:6 dilutions

Highest enhancement rate of vigour index (V.I.) was obtained with RCM 1:9 (1520) followed by 1:6 (1040)

New strategy for managing plant diseases Environmentally friendly Elicitors characteristically non-specific Induce general resistance effective against

a range of pathogens Able to reduce the level of infection Elicitors enhance resistance in response to

extrinsic stimulus without altering the genome

Only metabolic changes in plants help in defending against infections

Induced ResistanceInduced Resistance

CONCLUSIONS

Induced biochemical and molecular mechanisms of defense responses are generally correlated with enzymatic responses in plants

PAL, being first enzyme in phenyl propanoid pathway plays a major role in plant defense

In the current results PAL activity observed highest in susceptible RCM (1:9 and 1:6) treated pearl millet cultivar. PAL activity lead to induce resistance in RCM/ amino acid treated plants

CONCLUSIONS

Peroxidase is a useful marker of plant development, physiology, infection and stress

Current results show increase in PO activity in susceptible cultivar when treated with RCM and amino acids.

PO contributes to resistance by oxidation of phenolic compounds in pearl millet.

PO is a key enzyme in the biosynthesis of lignin that limits the extent of pathogen spread because of antimicrobial activity