WEST VIRGINIA APPLE CROP PROFILE
Aphids [rosy apple aphid, Dysaphis
plantaginea (Passerini); spirea aphid, Aphis spiraecola Patch]: Rosy apple
aphid is the most serious of the five aphid species found on apple, and is the most
important prebloom insect pest. It causes leaf, fruit and systemic root damage, and is
capable of causing up to 50% fruit injury in severe outbreaks. Spirea aphid is less of a
problem, causing discoloration of fruit from sooty mold growth on honeydew deposits only
under moderate to high populations.
Chemical control: In order to prevent fruit injury from rosy apple aphid, 1 to 2 insecticide applications are typically made during the prebloom period (green tip to half-inch green stage and tight cluster to pre-pink stage). If control is not achieved during the prebloom period, a rescue treatment is usually applied at petal fall, however, some fruit injury may still result. Spirea aphid control, if needed, usually consists of a single insecticide application (material used usually has efficacy against other pests present at the same time) about 4 to 6 weeks after petal fall.
|
|
Amount used |
|
Insecticide |
% of acres treated |
lb a.i./acre/application |
lb a.i./acre/year |
Chlorpyrifos |
10 |
1 - 1.25 |
1 - 1.25 |
Dimethoate |
15 |
0.75 |
0.75 |
Endosulfan |
3 |
1.50 |
1.50 |
Esfenvalerate |
38 |
0.03 |
0.03 |
Imidacloprid |
28 |
0.05 |
0.05 |
Biological control: Predation of aphids occurs by adults and larvae of ladybird beetles, and larvae of syrphid flies, aphid midges and green lacewings. This biological control is insufficient to prevent fruit injury and the need for insecticide application to control rosy apple aphid. Biological control of spirea aphid is likely to occur if greater than 20% of the aphid colonies have predators.
Cultural control: Removal of watersprouts in the center of trees will reduce populations of spirea aphids.