Efficacy of some microbial control agents against agrotis ipsilon and Heliothis armigera in Egypt

ABSTRACT

Tomatoes [family Solanaceae] are currently infested with Heliothis armigera and Agrotis ipsilon. The role of some microbial control agents was tested in the laboratory, in green house and in the field against insect pests which infect the tomato plants. Under laboratory conditions the results showed that the Lc[50] s of the entomopathogenic fungi Beauveria bassiana, Metarhizium anisopliae and Verticillium lecanii, when applied to greasy cutworm, A. ipsilon were 137, 156 and 178 spores/ml, respectively. The corresponding Lc[50s of the same fungi on the American bollworm H. armigera were, 134, 142 and 149 spores/ml, respectively. both insect pests were affected by B. thuringiensis, under laboratory conditions. In the green house, both insect pests were affected by the fungus B. bassiana more than with the other bioinsecticides. The Lc[50]s were, 130 and 151 spores/ml for a. ipsilon and H. armigera, respectively. Field experiments showed that infestation percentages of A. ipsilon 90 days after application of different treatments ranged between 20 and 40 and 10-44 in 2004 and 2005 crop seasons, respectively. The corresponding ranges of percentages of H. armigera were 20-34 and 11-41, while natural infestations were 79 and 87 for A. ipsilon and 70 and 89 H. armigerain both seasons, respectively, which indicate marked reductions in infestation of both insects in all treatment areas. Yield loss was significantly decreased when the tomato crop was treated with B. bassiana. M. anisopliae, V. lecanii and B. thuringiensis, respectively in both seasons 2004 and 2005 as compared to the control plots