Abstract
Field experiments were carried out at the experimental farm of the Faculty of Agriculture, Sohag, South
Valley University during two successive seasons, 2002 and 2003, to study the relative susceptibility of
some maize and sorghum varieties to infestation by greater sugar cane borers, Sesamia cretica L., and the
effect of chemical insecticide (methomyl), microbial insecticide (B.t.) i.e. Agrein, petroleum oil (Sisi 6),
and in organic salt (barium nitrate) against these pests, under field conditions. The roles of controlling
S. cretica by these materials in increasing the yield of maize and sorghum varieties were also studied.
Results revealed that all tested maize and sorghum varieties infested by S. cretica had significant
differences observed between them. Infestation percentage of S. cretica in maize and sorghum varieties
generally increased gradually with plant age. Data indicated that methomyl was the most effective
material in reducing the infestation of maize plants by S. cretica, followed by Agrein, Sisi 6, and barium
nitrate. The same potency order of tested materials on maize was also found on sorghum varieties during
the two seasons. Results also revealed that the reduction of S. cretica population play an important role in
increasing the yield of maize and sorghum. The yield of all treated plants was higher than that of
untreated plants. However, methomyl was the most active material followed by Agrein in controlling the
pest and resulted in increasing yield of all maize and sorghum varieties.