What Should You Spray Apple Trees With?
Apple trees of any variety are a wonderful addition to your landscape, whether dwarf or full size. Maintaining a spraying schedule to eliminate pests and disease will reward you with healthy, long living trees and juicy, sweet apples.
Apply a dormant-oil spray for fruit trees, per the manufacturer's instructions, in early spring--while the tree is still dormant, and as soon as green shoots appear on the apple tree. A dormant-oil spray will suffocate any insect eggs, like mites and aphids, that may have survived over the winter. Spray with dormant oil every two to three weeks over the growing season.
Do not spray during the blooming period, as it will affect--and possibly kill--the pollinating bees. Pesticide or insecticide sprays are often a mixture, and may also contain a fungicide. Pesticide spray should contain the chemical phosmet, which will control the common apple pests: plum curculio, European apple sawfly, codling moth, leaf roller and green fruit worm. Spray every 10 to 14 days, after bloom, throughout the growing season, until two to three weeks before harvest. It is important to follow the dilution instructions on the label. Insects are known to build up a resistance to pesticides over time, and spraying an over-rich solution only hastens that development.
Fungicide sprays are often mixed in with pesticide sprays for home gardens, but they can also be purchases separately. The chemical captan, or captan/benlate, should be sprayed when the first green growth on the apple tree appears to protect the tree from apple scab and other diseases. To protect the apple tree from summer diseases, spray the tree every two to three weeks until a few weeks before harvest. If captan is pre-mixed in with a pesticide, do not spray when the blooms are open and bees are pollinating. Do not mix captan with dormant oil spray, as the combination may cause foliage injury. Space the two different sprayings seven days apart.
Some sprays are designed to thin the apples on the tree, while others prevent the tree from producing apples. Several types of fruit-thinning chemicals are available at garden centers. These chemicals are usually sprayed at blossoming time, while some requiring a follow-up spray shortly thereafter.