Vegetos

Abstract

Natural parasitism of rice yellow stemborer, Scirpophaga incertulas (Walker) and leaffolder, Cnaphalocrocis medinalis (Guenée) in organically as well as conventionally grown basmati rice (Pusa Basmati 1121) was recorded at farmers’ field during 2012. Different stages of stemborer and leaffolder were collected and observed under laboratory conditions for the emergence of parasitoids to record natural parasitism. The parasitism in the eggs, larvae and pupae of rice stemborer and leaffolder ranged from 1.67 to 30.91 and 1.86 to 28.87 per cent in organic and conventional basmati rice, respectively. Egg parasitoids, Trichogramma chilonis, T. japonicum, Telenomus sp. were recorded from the eggs of rice stemborer. Braconid wasps, Stenobracon nicevillei and Bracon sp were recorded from the larvae of stemborer. Tetrastichus sp and Brachymeria sp were the pupal parasitoids with per cent parasitism ranging from 5.09 to 5.36 and 2.83 to 3.17 in conventional and organic fields. Larval parasitoids, Bracon sp and Cotesia sp were recorded from rice leaffolder and the parasitism ranged from 5.88 to 6.02. Pupal parasitoids, Tetrastichus sp and Brachymeria sp were recorded with parasitism ranging from 4.08 to 5.59 per cent.