Effect of biopesticides Bacillus thuringiensis var. kurstaki, Nucleopolyhedro-virus, spinosad and emamectin on Spodoptera exigua Hübner in laboratory and field conditions
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عنوان دوره: سومین کنگره بین المللی حشره شناسی ایران
نویسندگان
1Plant Protection Department, Agriculture Faculty, Urmia University, Urmia, Iran,
2Department of Plant Protection, Mahabad Branch, Islamic Azad University, Mahabad, Iran,
چکیده
Sugar beet (Beta vulgaris L.) is one of the main and strategic industrial crops, which has a major share in sugar production in the world. Beet armyworm (Spodoptera exigua Hübner) is one of the most important pests of sugar beet. Due to the problems associated with the use of chemical pesticides against this pest, the use of bio-pesticides in integrated pest management program is recommended. Therefore, in this research, effects of Bacillus thuringiensis subsp. kurstaki, S. exigua nucleopolyhedrovirus (SeNPV), Spinosad and emamectin were evaluated on the 1st larval instar of S. exigua in laboratory (25 ± 2 ºC,57 ± 2% RH and 16:8 h L:D) and at field conditions. In the laboratory experiments, LC50 values of different concentrations of B. thuringiensis, SeNPV, spinosad and emamectin were determined after 24, 48 and 72 h by probit analysis. Also, the effect of each compound was evaluated using Henderson- Tilton formula and GLM analysis after 1, 3, 7, 14 and 21 days in the field conditions. The results of probit analysis of different concentrations of Bt., spinosad and emamectin were 0.47, 0.410, and 978.158, 0.291, 0.172, and 687.938 and 0.218, 0.159, 595.714 mg/L after 24, 48 and 72 h, respectively, and those of SeNPV were 0.76 ×105, 0.856×105, 1.578×105 OBs/L, respectively. Moreover, the highest and lowest mortality were related to emamectin (95.33%), SeNPV virus (49.00%) after 21 days at field conditions. The highest percentage of damage was observed in the control (67.78%) and the lowest ones were recorded in emamectin and spinosad treatments (18.89 and 34.44%, respectively). Based on the laboratory and field results, spinosad and emamectin were the most effective compounds for controlling this pest and further studies are required to compare the mentioned treatment economically
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