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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.

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.

The overall goal of this research was to determine the effects of spirea aphid, Aphis spiraecola Patch, feeding and nitrogen fertilization on net photosynthesis (Pn), leaf chlorophyll content and greenneess, growth, dry matter accumulation, and carbohydrate concentrations of young apple trees, with comparisons to apple aphid, Aphis pomi DeGeer. Trees were artificially infested and grown in an unheated greenhouse with screened ends. The spirea aphid responded differently to various nitrogen treatments. Aphid density increased at a faster rate on trees receiving higher nitrogen application. The leaf nitrogen concentration increased significantly and linearly with increasing amount of urea application in both infested and control leaves. Also, a significant difference in leaf nitrogen concentration was found at each urea application rate between infested and control leaves. Spirea aphid feeding and sooty mold accumulations caused significant reductions in photosynthetic rates, leaf chlorophyll content, and greenness. Pn increased linearly with increasing chlorophyll content and greenness; nitrogen rates caused an increase in Pn and leaf greenness. Aphid-days accumulations were strongly correlated to Pn and greenness at each nitrogen rate applied. Accumulation of callose at the phloem sieve plates in response to spirea aphid feeding occurred but to a lesser degree than from other aphids reported on apple and pecan leaves. Accumulation of fresh and dry weights in all tree parts (leaves, lateral shoots, trunk, rootstock, and roots) during the growing season were affected by both spirea aphid and nitrogen fertilization. The spirea aphid reduced accumulation of fresh and dry weights in all tree partitions when trees were harvested at the end of the first growing season. These reductions were still lower than the control when trees were harvested at the ten-leaf stage the following spring. The spirea aphid caused a significant reduction in lateral shoot growth at the end of