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

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

Formation of mycotoxins by toxigenic fungi isolated from green coffee bean in Egypt

Isolates [991] of toxigenic fungi belonging to the genera Aspergillus and Penicillium were isolated from green coffee bean in Egypt and were tested for their ability to produce mycotoxinsFungi were identified and relative frequency of their occurrence and percentage of seeds infection was also studied Ochratoxins were produced by 8% of A ochraceus; whereas, six out of 109 isolates of PViridicatum and one isolate of P Cyclopium Aflatoxin B1 were produced by seven isolates of AFlavus [4.9%] Six out of 51 isolates of A versicolor formed sterigmatocystin Isolates of A niger, P frequentans and P. citrinum did not produce mycotoxins

Biological control of rhizoctonia solam using trichoderma viride and its relation to symbiotic nitrogen fixation by faba bean

A pot experiment was carried out using a clay loamy soil to study the efficacy of Trichoderma viride as a biocontrol for Rhizoctonia solani as well as its effect on biological nitrogen fixation by faba bean. Soil inoculation either with R. solani, Tl viride or in combination had no effect on total microbial counts in the rhizosphere soil of the faba bean. These treatments, however, enhanced the proliferation of fungal population in the rhizosphere. The infection with R. Solani induced retardation of nodulation and symbiotic nitrogen fixation. Control of the disease by T. viride resulted in normal nodulation and nitrogen fixation patterns as produced by the healthy [non infected] plants