At least 30 different insects, mites and diseases commonly attack apple trees in Connecticut. Unfortunately, they are not all present at the same time but appear in a definite sequence from the time buds break dormancy until the fruit is ready to be harvested. Therefore, it is not possible to apply two or three sprays and expect to harvest insect and disease-free fruit.
If the insect, mite and disease recommendations (contact your local Cooperative Extension center for up-to-date management options) are followed carefully, you should obtain a high percentage of clean fruit from a home planting. The proper timing of spray applications and thorough coverage of leaves and fruit are as important as the spray materials used. Be sure to cover all surfaces of the tree.
General-purpose mixtures have been found to be safe and effective for the control of fruit pests. This mixture is available under a variety of trade names at most garden supply shops. In addition, individual ingredients of various products are available in small packages and can be mixed at home prior to spraying.
| GROWTH STAGE | PESTS |
| Green Tip: when green tissue first shows from buds. | Red mite eggs and scale insects. |
| Half-Inch Green: when half-an-inch of green tissue projects from the buds. | Scab and rosy aphids. |
| Tight Cluster: about seven days after Half-inch Green when blossom buds appear in a tight cluster. Center bud may show some pink color. | Scab, rusts, black rot, powdery mildew, rosy aphid, leafroller and caterpillars |
| Pink: when blossom buds separate from the cluster and all show a pink color but before blossoms open. | Same as above plus red mites. |
| Bloom: when 10% or more of the blossom buds are in bloom | Scab, rusts, black rot and powdery mildew |
| Petal Fall: when 90% or more of the blossoms have fallen. Sprays applied sooner may kill pollinating insects. | Same as above plus curculio, codling moth, leafrollers and codling moth. |
| First Cover: about one week after Petal Fall. | Same as above plus sawfly. |
| Second Cover: about one week after First Cover. | Same as above plus apple aphid. |
| Third Cover: about two weeks after Second Cover, mid-to-late June. | Scab, fruit rots and spots. Apple aphids, curculio, codling moth and mites. |
| Fourth to Eight Covers: apply when needed until early September. | Scab, fruit rots and spots. Apple maggot, aphids, mites, leafrollers and codling moth. |
Contact your local Cooperative Extension Center for up-to-date management options including cultural practices, biological control and chemical control (organic and non-organic).
Revised by: Edmond L. Marrotte, Consumer Horticulturist, Department of Plant Science, University of Connecticut
Updated by: Mary Concklin, UConn IPM. 2012
The information in this document is for educational purposes only. The recommendations contained are based on the best available knowledge at the time of publication. Any reference to commercial products, trade or brand names is for information only, and no endorsement or approval is intended. The Cooperative Extension System does not guarantee or warrant the standard of any product referenced or imply approval of the product to the exclusion of others which also may be available. The University of Connecticut, Cooperative Extension System, College of Agriculture and Natural Resources is an equal opportunity program provider and employer.