Field evaluation of egg parasitoid Trichogramma chilonis against stem borer, Chilo partellus in Kharif maize

Abstract

Field trials were conducted to compare the augmentative releases of egg parasitoid, Trichogramma chilonis (Ishii) for the management of stem borer, Chilo partellus (Swinhoe) in maize growing areas of Punjab during 2015 and 2016. Each fi eld was divided into four blocks representing four treatments, viz., one release of T. chilonis @ 1,00,000 per ha on 10-15 days old crop, two releases of T. chilonis @ 1,00,000 per ha on 10 and 17 days old crop, chemical control (deltamethrin 2.8 EC @ 200 ml/ha) and untreated control. Based on the pooled mean, the dead heart incidence was significantly lower in chemical control (3.51%). Between the parasitoid treatments, double release of T. chilonis resulted in signifi cantly lesser dead hearts (4.27%) as compared to single release (5.44%). The per cent reduction in stem borer damage over untreated control was 48.29, 59.41 and 66.63 in single release, double release and chemical control, respectively. The mean increase in yield over control was 9.94, 13.75 and 17.75 per cent with net returns of ` 5248.75, 7105.50 and 9458.25 per ha in single release, double release and chemical control, respectively. Conclusively, two augmentative releases of egg parasitoid, T. chilonis @ 1,00,000 per ha; fi rst release on 10 days old crop and second a week thereafter, is recommended for stem borer management in Kharif maize.