Possibility of Aphis pomi control in apple orchards with azadirachtin

Abstract

Aphids occur regularly in apple orchards and cause severe damages. This research aimed to assess the efficacy of biological - azadirachtin (10 g a.i. L-1) 0.2% and chemical insecticides - chlorpyrifos + cypermethrin (50 + 50 g a.i. L-1) 0.1%, against Aphis pomi in apple orchard. The experiments were performed in 2013 and 2014 in Novi Slankamen, Celarevo and Bela Crkva (Serbia, Vojvodina) according to standard EPPO methods, on cultivar 'Golden Delicious'. Treatment was performed twice with azadirachtin in seven days interval and once with chlorpyrifos + cypermethrin. Three assessments were made: before the treatment, immediately after the second treatment and 10 days after the second treatment, on 10 previously marked shoots per replication, by counting the number of aphids. Efficacy (E%) was calculated according to Abbott. In 2013, the number of aphids in Novi Slankamen and Celarevo ranged from 58.7 to 70.0 before the treatment, and after seven days (26.5 to 33.5) was significantly lower than in the control (99.5 to 133.7). Insecticides efficacy was 66.3 to 79.6%. Ten days after the second treatment, the number of aphids (9.75 to 10.7) was significantly lower than in the control (135.5 to 148) and insecticides efficacy was 92.2 to 93.9%. In Celarevo and Bela Crkva in 2014 the average number of aphids before the treatment was 71.7 to 81.2 and after seven days (34.5 to 43) was significantly lower compared to the control (127.7 to 145.2) and the insecticides efficacy was 66.3 to 76.2%. The number of aphids (16.2 to 18.2), 10 days after the second treatment was statistically significantly lower compared to the control (160.5 to 160.7) and insecticides efficacy was 88.6 to 90.1%. Efficacy of tested insecticides was on the same level of significance thus it can be concluded that azadirchtin can ensure adequate protection from A. pomi in apple orchards.