EFFICIENCY OF THE FUNGUS, Beauveria bassiana (BALS.) AS A BIOLOGICAL CONTROL AGENT AGAINST Ostrinia nubilalis (HUB.) AND Chilo agamemnon (BLES.) IN MAIZE AND RICE FIELDS AT KAFR EL-SHEIKH REGION

The present investigation was achieved at sakha agricultural research station during 2008 and 2009 seasons to evaluate efficiency of the fungus beauveria bassiana (bals.) as a biological control agent in field applications against the european corn borer, ostrinia nubilalis (hub.) in corn fields (2008 season), the lowest concentration (2.5×107) induced 26.87% reduction, while 5×107 resulted 44.64% larval reduction, the highest concentration 1×108 conidia/ml resulted 58.23 % larval reduction. infested internodes were reduced in values ranging between 23.78% and 66.53 % at different b. bassiana concentrations. the highest concentration (1×108) reduced number of holes and number of broken tassels by 60.03 and 73.28 %, respectively. in 2009 season, reductions were 60.88, 62.63, 47.80 and 64.85 % for larvae, infested internodes, holes and broken tassels, respectively when the highest concentration (1×108 conidia/ml) was applied. treated rice plots (2008 season) by b. bassiana against the rice stem borer, chilo agamemnon (bles.) reduced dead hearts by 20.29, 43.59 and 55.0 % fifteen days post treatment. more reduction in dead hearts were obtained 30 days after treatment; 24.23, 50.17 and 71.88 % at 2.5×107, 5×107 and 1×108 conidia/ml, respectively. also, white heads were reduced, 30 days post treatment, by 34.87, 56.23 and 70.88 at 2.5×107, 5×107 and 1×108 conidia/ml, respectively. in 2009 season, 30 days after applications, dead hearts were reduced by 26.48, 51.68 and 73.30, while white heads were reduced by 35.34, 62.26 and 72.04 % for 2.5×107, 5×107 and 1×108 conidia/ml, respectively. thus, two sprays by the fungus at two concentrations could be applied to get sufficient reduction in reducing the infestation by o. nubilalis and c. agamemnon in maize and rice fields.