Apple, Timing Sprays for Rosy Apple Aphid Control, 1980

Insecticides were applied at various times of the season to determine the optimum time to control the rosy apple aphid. Each treatment was applied to 4-tree plots in a randomized block design with each plot consisting of a Rome, Golden Delicious, Delicious, and York Imperial tree. Each treatment was replicated 4 times. The sprays were applied with a handgun using a John Bean high pressure sprayer equipped with a 35 gpm pump. Refer to the table for the timing of sprays and phenological development of apple. Effectiveness of the sprays was evaluated by examining the entire tree and determining the number of infested clusters, the number of infested leaves, and the number of injured apples/tree. A leaf or cluster was considered infested if it contained one or more live aphids.