Fungicide sprays in April and May are necessary to prevent diseases common to most susceptible varieties of apple trees. When leaves appear, it’s time for the first application.
Myclobutanil (Immunox, Fungi-Max and F-Stop Lawn and Garden Fungicide) is effective for controlling apple scab and cedar apple rust which are problematic in April and May. Applications should be made on a 7-10-day schedule.
For summer disease control look at Bonide Fruit Tree and Plant Guard. This insecticide/fungicide can be applied after the petals drop and is effective against sooty blotch and fly speck.
For organic treatments, Cyd-X is labeled for apple trees to control against codling moth. Apple bagging is a method of protecting fruit by covering it with a brown bag, think lunch bag, and restricting access for pests and diseases. This can be done in combination with early season fungicide applications to provide season-long protection. Here is a reference video to learn how to bag apples. University of Kentucky Extension – Apple Bagging
***Always follow the label recommendations and do not use insecticides during bloom period.
The best prevention for diseases and pests is proper cultural care. Thinning fruit to give at least 4-6 inches between each apple allows better spray coverage and reduces protection for codling moth larvae. Fruit that are found to be infected should be destroyed to prevent further infection/infestation. During dry spells, provide supplemental water to fruit trees throughout the root zone. Stake young trees and secure with a wide material that will not cut into the tree trunk. Maintain a 3-foot diameter weed-free barrier around trees to remove host plants and protect against damage from mowing. This will also remove competition for nutrients and water. If mulch is added, keep it a few inches away from the trunk.
You can read more by accessing our KSRE publication: Spray Guide for Growing Apples at Home
Peaches, Nectarines and Apricots
Late frost can prevent fruit from setting on these trees especially if they are in full bloom. Trees that will not develop fruit as a result of late frost do not need to be on a spray schedule. Trees that will bear fruit can be treated with a product that contains captan or myclobutanil (Immunox, Fungi-Max, Fertilome F-Stop Lawn and Garden Spray) from now until about two weeks before harvest with applications every ten days.
Visit the KSRE website Common Plant Problems to see treatment options for specific problems pertinent to fruit.