Population sampling of planthoppers, leafhoppers and insect predators on broadcast rice, treated with carbofuran, in Eastern Sri Lanka

Abstract

A survey of planthopper and leafhopper assemblages and insect predators was conducted in the rice fields of Kaluvanchikudi in Batticaloa District and Kohabana and Central Camp in Amparai District during the dry (yala) season in 1989. Nilaparvata lugens (Stal) was the predominant planthopper species in these rice fields; Sogatella furcifera (Horvath) comprised less than 10% of the sample in any field. The leafhopper species collected included Nephotettix nigropictus (Stal), Nephotettix virescens (Distant), Recilia dorsalis (Motschulsky), and Cofana (=Tettigella) spectra (Distant). Nephotettix species were predominant in Kaluvanchikudi and Kohabana, while R. dorsalis was dominant in Central Camp. Insect predators included the mirid, Cyrtorhinus lividipennis Reuter, an anthocorid, Orius tantillus (Motschulsky) and two coccinellids, Harmonia octomaculata (Fabricius) and Micrapsis discolor (Fabricius). Application of furadan granules reduced the planthopper and leafhopper populations drastically, but did not appreciably reduce the insect predator population.