Bio-diversity and Seasonal Activity of Arthropod Fauna in Brassicaceous Crop Ecosystems of Meghalaya, North East India

Abstract

Biodiversity of arthropod fauna was assessed in brassicaceous ecosystems of Meghalaya during 2010-12. Three species of aphids viz., Liphaphis erysimi , Brevicoryne brassicae and Myzus persicae and large white cabbage butterfly ( Pieris brassicae ) were found to be a major pests of brassicaceous plants in this region; while pentatomid bugs ( Nazara viridula ), flea beetle ( Phylletreta cruciferae ), leaf beetle ( Monolepta signata ), saw fly ( Athalia lugens proxima ) and small white cabbage butterfly ( Pieris repae ) were appeared to be a minor pests. Natural enemies, especially, predators of aphid viz., coccinellid beetles, syrphids flies and spiders were recorded in this ecosystem. Parasitoids include nymphal-adult parasitoid of aphids, Diaeretiella repae , larval parasitoids of cabbage butterfly, Hyposoter ebeninus and Cotesia glomerata . Besides, activities of several pollinators were also observed during flowering stage. Major predators of aphids were Coccinella septumpuncata complex and C. transvarsalis complex. This study also recorded a seasonal activity of above mentioned pests and natural enemies and it would certainly be useful in understanding the biodiversity and role of different tropic levels in this ecosystem.