control of green peach aphid by using fungus, metarhizium anisopliae, and imidacloprid, on three canola cultivars, under microcosm conditions

the effect of the fungus, metarhizium anisopliae, sub-lethal dose of imidacloprid, the aphid, myzus persicae and the three canola cultivars under microcosm conditions inside plastic cages in greenhouse (27 ± 3°c, rh 90 ± 5 %) indicated that field and semi-field concentrations of the fungus significantly reduced the population of green peach aphid (gpa) as well as in combination with lc10 of imidacloprid. comparison of mean percent of the gpa mortality, 7 and 23 days after treatment, indicated the distribution of pathogen inside the aphid population. comparing different treatments determined that not only imidacloprid had no negative impact on pathogenicity of fungal pathogens but also increased the efficiency of the fungus.the highest and lowest mean value of plant dry weight was concerned to the licord in treatment containing field concentration of the fungus plus imidacloprid (4.57 ± 0.48 gr) and the rgs003 cultivar in treatment including sublethal dose of imidacloprid (1.29±0.27 gr), respectively and there was significant difference between them. comparison of different cultivars showed the highest mean number of the gpa colonisation on the zarfam (2040.50±126.92 aphids) and the lowest one (1583.17±213.17 aphids) on the rgs003 cultivar, respectively but no significant difference was observed between zarfam and licord cultivars. the results indicated that using semi-field concentration of m. anisopliae added with lc10 of imidacloprid in compared with the other treatments to control the gpa could be the best alternative. in addition to cause remarkable mean mortality percent after a week, the less fungal concentration was applied.