Biological Control of Sugarcane Top-borer, Scirpophaga excerptalis (Walker) (Lepidoptera: Crambidae) through Different Release Levels of Telenomus beneficiens (Zehntner) (Hymenoptera: Scelionidae)

Telenomus beneficiens is a common egg parasitoid of sugarcane top borer Scirpophaga excerptalis; however, in winter time the incidence of the parasitoid on top borer eggs is extremely low. T. beneficiens adults were released at various time durations into sugarcane plots to evaluate the parasitic potentiality of the parasitoid against sugarcane top-borer. The egg parasitoid T. beneficiens of sugarcane top borer Scirpophaga excerptalis (Walker), was released into four sugarcane plots as once, twice, thrice and quadruple time treatments to compare its parasitic potential as a biological control agent. The four releases of the adult parasitoid were made within a time interval of one month and at a rate of ۵۰۰ adults per plot. Results revealed a significant control of the pest through all the four treatments. The highest mean parasitism of ۴۲.۳۶±۱۰.۸۴% and lowest mean infestation of ۱۲.۰۵±۰.۹۹% was recorded for the treatment of quadruple releases, followed by the triple release plot, where ۴۱.۳۸±۱۰.۰۷% of mean parasitism and ۱۲.۶۱±۰.۷۸% of mean infestations were observed. As for the double release plot, ۲۶.۵۶±۳.۷۲ and ۱۴.۴۶±۱.۹۲% mean parasitism and infestation were recorded respectively, whilst in the single release plot, the corresponding figures equaled to ۲۱.۹۴±۲.۹۸ and ۱۶.۸۲ ±۲.۳۸% as compared with the check plots (۱۵.۷۱±۳.۰۳ and ۱۶.۸۲±۲.۵۵ %). It is evidenced that triple release results almost coincide with the quadruple release ones, and hence the triple release of the adult parasitoid is effective enough and recommended for the control of sugarcane top borer, S. excerptalis.