The lethal effects of entomopathogenic fungi Metarhizium anisopliae isolets against 2nd nymphal stage of filbert aphid Myzocallis coryli

The greatest damage to hazelnut is due to its pests. Filbert aphid Myzocallis coryli is one of the important pests of this tree. In order to reduce the population of hazelnut aphids, which causes severe damage to this plant, the use of biological control method based on insect pathogenic fungi in laboratory and field conditions is purposed. In this study, the effects of four isolates DEMI001, IRAN 715C, M14, V245 of M. anisopliae were used and evaluated on the second instar nymphs in laboratory (25±1 °C, 65±5% relative humidity and photoperiod 16: 8 hours dark: light) and field conditions (30±3 °C, 55±6% relative humidity and photoperiod 14:10 dark hours: Ligh). In order to evaluate the effects of four isolates from the lethal concentration for 50% of the population (LC50) probit analyses program of SPSS-21 software was used. The LC50 value achieved from the effect of, IRAN 715C, DEMI001, M14 and V245 isolates on the second instar nymphs of the aphid in laboratory and field conditions were 5. 13 ×107, 3.00 ×106, 3 . 09 ×107, 1.11 ×106 (spores/ml) and 5. 03 ×107, 1.81 ×106, 0.43 ×106, 1.5×106 (spores/ml), respectively. The results of this study showed that the isolate M14 is more effective on the second instar nymphs of this aphid. Also, for controlling the aphids’ nymphs in field conditions, a higher concentration of fungal suspension is required compared to experimental conditions. In evaluate interaction between two isolates additive or synergistic effect was not observed.