Exploitation of Plant Products and Bioagents for Ecofriendly Management of Chilli Fruit Rot Disease

Abstract

Forty four plant species and eight antagonistic organisms were tested against Colletotrichum capsici and Alternaria alternata, the causal agents of fruit rot disease of chilli. In vitro studies indicated that leaf extracts (10%) of Abrus precatorius (Gundumuthu) and Aegle marmelos (vilvum), demonstrated the highest inhibition of spore germination and mycelial growth of these two pathogens. Among the fungal and bacterial antagonists tested, Trichoderma viride isolate 3 and Pseudomonas fluorescens were very effective in inhib- iting mycelial growth of the pathogens in vitro. In the pot culture experiment, two sprays with leaf extract of A. precatorius (10%), first spray 20 days after fruit set and the second spray 2 days after inoculation with the pathogens, resulted in the lowest disease incidence (23.95%) and intensity (27.60 PDI - Per cent Disease Index) as compared to 71.50% incidence and PDI of 78.20 in the control. Among the antagonistic microorganisms two sprays of talc-based formulation of P. fluorescens (2%) were very effective in reducing the disease intensity (35.70 PDI). However, the leaf extracts and antagonistic organisms only ranked next to the fungicide (carbendazim 0.1%) (18.05 PDI). Field evaluation of the effective plant extracts, antagonistic microorganisms and fungicide revealed that spraying with A. precatorius leaf extract (10%) twice, the first spray at the time of fruit set and the second spray 20 days after fruit set caused the maxi- mum disease reduction (25.53 PDI) followed by a single spray of the same leaf extract (10%) on 20th day after fruit set (28.50 PDI).