Relative Composition of Egg-parasite Species of Nilaparvata lugens, Sogatella furcifera, Nephotettix virescens and N. nigropictus in Paddy Fields in Thailand

Abstract

A search for natural enemies of leaf and planthoppers, especially egg parasites, for use in the integrated control programme, was carried out during 1976-78 in the Central Plain, the north and the north-east of Thailand. Parasitised batches of eggs of Nilaparvata lugens (Stål), Sogatella furcifera (Horv.), Nephotettix virescens (Dist.) and Nephotettix nigropictus (Stål) were collected from the paddy fields and kept under room conditions for the emergence of adults of parasites; the parasites were then identified. Paracentrobia garuda Subba Rao, Oligosita sp. A and Conatocerus sp. were found to be the egg endo-parasites of N. virescens and N. nigropictus in the north and the north-east. Oligosita sp. A had never been found in the Central Plain. P. garuda was dominant in the north while Oligosita sp. A was dominant in the north-east in 1976 and 1978. Anagrus sp. and Oligosita sp. B were egg endo-parasites of N. lugens and S. furcifera. Anagrus sp. was a dominant egg endo-parasite of S. furcifera both in the north and the Central Plain, and in the Central Plain of N. lugens. The host-specificity of these rjarasites was also observed.