Effect of Bio-Rational Approaches on the Larval Population and Pigeonpea Pod Damage by Exelastis atomosa (Wlsm.)

Paras Nath,S N Rai,R S Singh,Ram Keval

doi:10.5539/jas.v9n3p98

Abstract

Effect of bio-rational approaches such as intercropping and application of bio-pesticide on the larval population, pod damage, grain damage and grain weight loss by plume moth (Exelastis atomosa (Wlsm.)) infesting pigeonpea (Cajanus cajan (L.) Millsp.) was studied. Pigeonpea intercropped with maize, pearl millet, sorghum, rice and black gram had significant effect on the larval population of plume moth when compared with pigeonpea sole crop infestation. The pigeonpea pod damage, grain damage and grain weight loss due to larval infestation in different pigeonpea intercrops and pigeonpea sole crop differed significantly however few exceptions were also recorded. The average larval population, pod damage, grain damage and grain weight loss in different intercrops varied from 0.25 to 0.39 larva/plant, 1.29 to 1.79%, 0.41 to 0.55% and 0.25 to 0.35%, respectively. The pigeonpea sole crop had recorded relatively higher larval population (0.39 larva/plant), pod damage (2.03%), grain damage (0.85%) and grain weight loss (0.59%) than the intercropped pigeon pea. The two sprays of NSKE 5% (first at flowering and pod formation stage and second after 20 days) were found superior in reducing larval population, pod damage, grain damage and grain weight loss. However, the plots devoid of any biopesticidal treatment had maximum larval population (0.68 larva/plant), pod damage (2.75%), grain damage (0.86%) and grain weight loss (0.60%) by E. atomosa.

Highlights

The pigeonpea (Cajanus cajan (L.) Millsp.) is a perennial legume from the family Fabaceae (Fuller & Harvey, 2006)
The ecofriendly biopesticides i.e. NSKE (5%), Nimbecidine (1%) and Bacillus thuringiensis kurstaki (Btk) (Halt 1.5%) were applied in two different schedules in the pigeonpea grown as intercrop and sole crop
The plume moth larval population, pigeonpea pod damage, grain damage and grain weight loss recorded in the pigeonpea intercrops and sole crop differed significantly

Summary

Introduction

The pigeonpea (Cajanus cajan (L.) Millsp.) is a perennial legume from the family Fabaceae (Fuller & Harvey, 2006). Among the biotic factors more than 200 species of insects have been found feeding on pigeonpea, only a few of those cause significant and consistent damage to the crop (Lateef & Reed, 1990). Number of these insect pests are found chewing and sucking on pigeonpea plants from seedling to harvest and no part of plant is immune to attack. The pod borer complex led by H. armigera as major pest incurred 70%-80% of yield loss, and this loss was well supplemented by pod fly (70%-80%), blue butterfly (4%-10%) and plume moth (5%-10%) in pigeonpea (Sharma et al, 2010). Among the various lepidopteran pigeonpea pod borers, four species i.e. H. armigera, E. atomosa, L. boeticus and jas.ccsenet.org

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Conclusion