Effects of Beauveria bassiana isolates on Trogoderma granarium Everst. under laboratory conditions
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عنوان دوره: سومین کنگره بین المللی حشره شناسی ایران
نویسندگان
Plant Protection Department, Agricultural Faculty, Gaziosmanpasa University, Tokat, Turkey,
چکیده
Stored grain insect pests can reduce weight, quality, seed viability and commercial value of stored grains. Management of these pests mainly relies on synthetic insecticides and fumigants. Negative effects of these pesticides have urged the researchers to develop alternative and environmentally friendly management strategies such as microbial control. Microbial control strategy uses living organisms called microbial control agents and entomopathogenic fungi are one of these agents. The objective of the current study was to assess the efficacy of entomopathogenic isolates of Beauveria bassiana (GOPT-517, GOPT-552, GOPT-562, GOPT-592 and GOPT-598) against khapra beetle (Trogoderma granarium Everst.). The efficacy of fungal isolates against T. granarium was tested by insect dipping method. The adult insects were dipped into different conidial concentrations (1 × 103, 1 × 105, 1 × 107, 1 × 108, 1 × 109 conidia/ml) for 5 second. The insects were then transferred to glass vial (ten insects per vial) containing ten healthy and clean wheat grains as a food. The vials were incubated at 25±1 °C, full darkness and, 75% RH for 14 days. The treated adult insects were checked for mortality after 1th, 7th, 9th, 11th, and 14th days of incubation. Dead insects were transferred to humid sterile glass Petri dishes (90 mm in diameters) to determine the mycosis rate. The cumulative mortality in adults 9 days after exposure to isolates of B. bassiana ranged between 34% and 78% for 1 × 109 conidia / ml concentration of the isolates tested. The highest mortality rate (80%) was obtained after 11 days of incubation period with isolate GOPT-517 at 1 × 109 conidia / ml concentration. The highest mycosis rate (100%) was obtained at the end of the 14th day with all the isolates in 1 × 109 conidia / ml. The results indicated that these isolates caused high mortality and exhibited higher mycosis rate. Further storage trial with these isolates should be conducted to consider them as potential biocontrol agents
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