Invasive Species Compendium

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Abstract

Seasonal variation in the windborne movement of insect pests over northeast India.

Abstract

A net supported by an aerodynamically shaped balloon (kytoon) was used to sample the insect fauna flying at about 150 m above a site in West Bengal, India, during 4 periods of the year: March, May, Oct. and Nov. Amongst the insects captured were some economically important rice pests (Nilaparvata lugens, Sogatella furcifera, Nephotettix spp. and Cnaphalocrocis medinalis), some of their natural enemies, and also pest aphids (e.g. Lipaphis erysimi, Aphis gossypii and Rhopalosiphum rufiabdominalis). Insect aerial densities aloft often remained high until late in the night, indicating that migration over large distances (even hundreds of km) was in progress; such movements would lead to redistribution of both pest and beneficial insects over large areas of north-eastern India. Differences between aerial densities and migration rates found for the 4 months are interpreted in terms of seasonal cropping patterns and weather, and aerial densities of N. lugens, C. medinalis, aphids, and the mirid Cyrtorhinus lividipennis are compared with values found in aerial netting studies elsewhere. From authors' summary. KEYWORDS: TROPAG | pest insects | winds | aerial surveying | seasonal variation | population change | surveys | INDIA | West Bengal.