Diversity and abundance of phytophage hemiptera in an irrigated rice ecosystem of Tamil Nadu, India.
A total of 24 taxa of phytophage hemipterans were recorded in weeded and partially weeded rice ecosystems during kharif 2001 in Tamil Nadu, India. Among them, 13 taxa, i.e. Brevennia rehi, Hysteroneura setariae, Nilaparvata lugens, Nephotettix virescens, Cofana spectra, Recilia dorsalis, Sogatella furcifera, Nezara viridula, Dolycoris indicus, Menida histrio, Scotinophara lurida, Leptocorisa acuta and L. oratorius, showed greater abundance in weeded rice ecosystem, while the rest of the species of phytophage hemipterans exhibited more abundance only in partially weeded plots. The diversity of delphacids had perfect similarity throughout the season. During tillering and flowering stages of the crop, cicadellids, pentatomids and red spotted bug exhibited greater diversity (=less similarity). Earhead bugs showed higher diversity during flowering and dough stages. Aphid exhibited perfect similarity in the first and second week, and was absent from the third week to seventh week. A total of 18 weed species acted as alternate hosts for polyphagous phytophage hemipterans were recorded in partially weeded plot. Of them, Cyperus iria, C. difformis, C. rotundus, Echinochloa colonum [E. colona], E. crus-galli, Ipomoea aquatica and Marsilea quadrifolia were dominant.