Predators and parasitoids of rice insect pests under rice ecosystems of Manipur valley

Abstract

Field surveys on predators and parasitoids of rice ecosystem during kharif season (2012–2014) in the four valley districts (Imphal East, Imphal West, Thoubal and Bishnupur) of Manipur were conducted. Altogether 33 species of predators belonging to 26 genera under 15 families of 5 orders and 15 species of parasitoids belonging to 5 families of Hymenoptera were listed. Among the predators, spider (Pardosa pseudoannulata Boes et. str. Tetragnatha maxillosa Thorell and Oxyopes javanus Thorell), damselflies (Agriocnemis femina Brauer, Agriocnemis pygmeae Rambur and Ishnura aurora Hagen), and dragonflies (Orthetrum sabina Drury and Sympetrum sp.) were found as dominant species. In case of parasitoids Cotesia rufricus Haliday and Apanteles sp. were found to be dominant in all the rice fields. One way ANOVA was done to evaluate the variation in the distribution of predators and parasitoids among the four study sites: among the predators, spider was found to be dominating (73.0) over other groups in Site 4 (Bishnupur District) whereas among the parasitoids, Cotesia rufricus (11.0) was dominating in Site 1 (Imphal East). The data revealed the significant variation in the distribution of predators and parasitoids (p<0.01). It was also observed that spiders existed with maximum density in all the four sites (57.4–73.0) while among the parasitoids, Cotesia rufricus was observed with maximum density (5.4–11.0).