Species diversity of predators on sucking pest complex in mulberry gardens of West Bengal

Abstract

Mulberry, the sole food plant of silkworm, Bombyx mori (Linnaeus) is invaded by a variety of polyphagous pests, severely hampering sericulture. Present study was conducted to identify natural species diversity and population dynamics of native predators of major sucking pests of mulberry in tropical ecosystem of Eastern India. Seasonal incidence of major sucking pests (thrips, mealybug and whitefly), species diversity and population dynamics of their native predators on unsprayed (n=6) was compared with sprayed (n=6) mulberry gardens during 2014-15. At least eighteen predators that were consistently associated with the sucking pests of mulberry were collected in the unsprayed gardens. Major predators of thrips were Micraspis discolor and Micraspis crocea. The mealybugs were predated by chrysopid, Mallada desjardinsi (Navas) and coccinellid species Menochilus sexmaculatus, Coccinella septempunctata, Scymnus sp, Scymnus coccivora, S. bourdilloni, S. nubilus, S. pallidicollis, S. pyrocheilus, Nephus bipunctatus, Nephus sp. nr. roepkei and Nephus regularis. Two species of whiteflies, Dialeuropoda dicempuncta Quaintaince & Baker and Aleuroclava pentatuberculata Sundararaj & David were predated by Brumoides suturalis, Jauravia pallidula, Serangium parcetosum and Chilocorus sp. The sprayed mulberry gardens conspicuously indicated non-specific elimination of the insect species with reduced species richness and abundance. Biodiversity indices were calculated for the sprayed and unsprayed gardens and the results emphasized the relevance of conservation biological control to reduce pest burden in mulberry and to promote species diversity.