Effects of winter pruning intensity on the interactions between the apple tree and rosy apple aphid Dysaphis plantaginea (Hemiptera: Aphididae)

Winter pruning is known to affect aphid infestation and plant growth, but no experimental results have been reported on how this cultural practice affects apple tree–aphid interactions. For this reason, the present field study aimed to assess the effects of increased winter pruning on apple tree–rosy apple aphid interactions. These effects were evaluated by examining tree vegetative growth, aphid dynamics, and fruit yield. The results indicated that vegetative growth increased with increased pruning. The aphid infestation lasted for six weeks in the netted row and became heightened when the pruning level rose, whereas the final growth rate of the shoot was not affected by pruning intensity or aphid infestation index. High levels of infestation induced leaf curling and leaf fall, causing stunted growth. The fruit growth parameters were found to be dependent on pruning intensity and aphid infestation index. Fruit diameter and fresh weight both decreased with increased pruning intensity but were not affected by aphid infestation. Decreases in pruning intensity and aphid infestation elevated fruit yield. Our findings lay a foundation that will help to improve our understanding of the interactions between D. plantaginea and apple trees.