University of Maryland Extension

Common Problems of Apples & Pears

trunk with frost crack
Cultural and Environmental 

worm inside of apple
Insects

apple with blotch and flyspeck
Diseases

grackle
Wildlife 

Back to apples

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Cultural Management Practices for Reducing Problems with Pome Fruits
  • Plant disease resistant cultivars - apples  -  pears
  • Regular dormant pruning.
  • "Ugly Stub" pruning method to remove fire blight symptoms.
  • Crop waste removal. The spores that initiate apple and pear scab in the spring come from fungal structures that have overwintered in the leaves under the trees. Thorough shredding or removal of these leaves in fall can provide a significant level of early season scab control. Fallen leaves also harbor the overwintering stages of several insect pests. Also, be sure to include all nearby flowering crab apples in this sanitation effort.
    Several insect pests and fungal pathogens cause young fruits to fall early. Collecting and destroying these infected fruits regularly during the growing season (from the tree or ground) helps keep these organisms from continuing their lifecycle through additional generations on other fruits. Apples should be thinned early in the spring to create a 6-inch spacing between fruit. When thinning, remove those fruits that are deformed, infested with insect pests, or infected by diseases. This thinning process will lead to larger fruit and fewer disease and insect problems.
  • Nitrogen fertilization. Applying too much nitrogen fertilizer, whether from organic manure or inorganic sources, has several negative effects. High nitrogen levels reduce the amount of fruit set, encourage high populations of aphids and psylla insects, and can lead to severe limb damage if fire blight develops. Also, excessive nitrogen is readily leached from the soil by water and can have negative effects on the ecology of streams, lakes, and the Chesapeake Bay. Do not fertilize apple trees if yearly shoot growth exceeds 12 to18 inches.
  • Weed, grass, and juniper control. Brush (including root sucker shoots), weeds, and grasses allowed to grow under and around fruit trees harbor a variety of insect pests from leafrollers and plant bugs to mites. Therefore, brush growth needs to be kept under control and prevented from accumulating. Even in the winter, weedy trash under and around fruit trees provides nesting sites for mice that feed on tree bark and roots during the winter. Be aware of junipers in the area, which serve as the alternate host for 3 types of rust fungi that infect apples. Where possible, remove junipers or do not plant junipers near apple trees. Where the junipers are already part of your landscape or your neighbor’s, inspect them closely in the fall and cut out any galls found on small branches. The following spring, monitor suspect junipers during rainy periods and remove any remaining galls with their showy, bright orange fungus growth before they dry down and release spores to the air. 
  • Consider painting the trunks and large scaffold branches of young trees with white latex paint to prevent bark damage. Failure of trees to properly harden off makes them more vulnerable to frost crack and sunscald injury. Avoid late summer-early fall pruning or fertilizing. 

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