Effect of cereals on the development of Sitotroga cerealella (Olivier) (Lepidoptera: Gelechiidae) and subsequent quality of the egg parasitoid, Trichogramma chilonis (Ishii) (Hymenoptera: Trichogrammatidae)

The effect of seven cereals viz., sorghum, wheat, oats, millet, paddy (Un-husked rice), barley and corn (Maize) which were fed to Sitotroga cerealella to induce the development and egg production of variable size by the moths, and potentially improving the parasitism and sex ratio of Trichogramma chilonis raised on eggs from moths were compared by measuring development from different larva diets. The first generation S. cerealella moths showed the highest adult progeny observed in sorghum (76.0) followed by wheat (75.3), oat (73.0), millet (70.8), and paddy (67.6), barley (66.8) and corn (51.0) which was significantly less than all others. Developmental period was significantly higher in corn and oats followed by wheat, barley, and millet and significantly lower in paddy and sorghum. The tested cereals had a pronounced and significant effect on adult weight from highest to lowest in the following order: corn greater than wheat greater than barley greater than paddy greater than sorghum = oat greater than millet. In the second generation, there was considerable and significant effect on adult progeny. Developmental period and adult weight varied in same sequence as recorded in 1st generation. Fecundity and egg size differed significantly among moths fed with various tested cereals. Significantly larger eggs were produced from adults reared on corn followed by wheat, barley, paddy, oat and millet. Parasitism and adult emergence by Trichogramma were higher in larger host eggs by adults grown on corn and wheat, followed by host eggs received from adults reared on barley, paddy and sorghum. Wasp performance was lower in small size eggs from adults raised on millet followed by oats. The highest number of females' emergence was produced on large sized eggs from corn-fed hosts, followed by in order by sorghum, wheat, paddy, millet, barley and oat.