BIODIVERSITY AND BIOCONTROL PROSPECTS IN MULBERRY GARDENS OF WEST BENGAL WITH SPECIAL REFERENCE TO NEW PREDATOR SCYMNUS LATIFOLIUS. SP. NOV ON MEALYBUGS INFESTING MULBERRY

Abstract

Mulberry, the sole food plant of silkworm, Bombyx mori (Linnaeus) is invaded by various polyphagous pests, causing economic loss in sericulture. Native predators in the plant ecosystem play a vital role in checking the pest infestation. In the present study, population dynamics, phenology of the arthropod predators of Paracoccus marginatus Williams and Granara de Willink and Maconellicoccus hirsutus (Green) infesting mulberry in four sericulture practicing districts (Murshidabad, Nadia, Birbhum and Malda) of West Bengal was studied. A diverse assemblage of alternate hosts and arthropod natural enemies were found associated with mealybugs infesting mulberry in the Indo gangetic plains of West Bengal. About 53 plant species acted as alternate hosts in the adjoining plots of mulberry gardens and profoundly influenced the population dynamics of mealybug pests and its associated predators and allowed migration rapidly from alternate hosts to mulberry as soon as the new flushes appeared after pruning. Sixteen predator species, were found consistently associated with mealybugs during the study. They are Brumoides suturalis (F), Coccinella septempunctata L., Jauravia pallidula Motschulsky, Menochilus sexmaculatus (F), Nephus regularis Sicard, Nephus sp. nr. roepkei de Fluiter., Nephus bipunctatus Kugelann, Scymnus bourdilloni Kapur, Scymnus coccivora Ayyar, Scymnus nubilus Mulsant, Scymnus pallidicollis Mulsant, Scymnus pyrocheilus Mulsant, Spalgis epius (Westwood), Mallada desjardinsi (Navas) and one anthocorid bug. Apart from these arthropods, one new species of Scymnus Kugelann, Scymnus (Pullus) latifolius Poorani sp. nov, was collected and reported for the first time. The predatory potential of the new predator was studied and amenability of the predator for mass multiplication in laboratory conditions opened avenues for its use as a potential biocontrol agent for checking mealybug pests in various agroecosystems.