Department of Entomology, Rajendra Agricultural University, Pusa, Samastipur-848 125, Bihar (India).
The seasonal prevalence of larval and pupal parasitoids of sugarcane top borer, Scirpophaga excerptalis Walker was studied for two years in spring, autumn and ratoon cane crops. Stenobracon deesae Cam. exhihited peak larval parasitisation to the extent of 39.54, 52.92 ad 54.23 per cent in August in spring, autumn and ratoon crops, respectively. The other larval parasitoid, Rhaconutus scirpophagae Wlk. similarly showed maximum parasitisation in August, being 33.42, 24.36 and 29.88 per cent in these three respective crops. However, Elasmus zehntneri Ferr. parasitised the borer larvae to a maximum of 14.17, and 11.31 per cent in spring and autumn crops, respectively. But, in ratoon cane the maximum parasitisation (9.29%) was in October. The pupal parasitoid. Isotima javensis Roh. revealed maximum parasitisation (6.67% in June In spring crop, whereas it was 15.28 and 6.25 per cent in autumn and ratoon canes, respectively in August. However, Stenobracon deesae Cam. was the most prevalent parasitoid in all the cane crops during both the years.
