Threats

• Apple trees can be difficult to manage against pest, weed and fungal risks. Apple maggots are one of the most problems in apple orchards and controlling them is often essential to protect your apple crop. Commercial growers can usually survive the apple maggot with standard management practices, but home growers often have more trouble. The apple maggot causes fruit to drop before it ripens and can renders already ripe fruit inedible. In addition to the maggot, apples can be lost to fungal or bacteria diseases.
  
  

Sanitation Practices

• Before resorting to sprays, observe good sanitation practices on apple trees to prevent and control disease. Getting rid of fallen apples quickly is essential to preventing infestations of the apple maggot. Regular fruit thinning prevents breakage and collapse of branches and reduces the number of fallen apples. Clearing leaves from the base of apple trees, burying fallen apples, and pruning dead or infected fruit and branches are important to prevent diseases.
  
  

Fungicidal Sprays

• If trees show signs of fungus, such as leaf yellowing or curling, consider a fungicidal spray. According to horticulturists at the University of Minnesota and University New Hampshire, the best sprays for controlling fungal diseases like apple scab, powdery mildew and black rot are captan and lime-sulfur sprays. Some fungal infections, such as sooty blotch and flyspeck, are generally harmless to fruit and can be safely ignored. Some sprays contain several antifungal ingredients and are usually labeled for most common apple tree diseases. Spray relatively early, shortly after buds open and leaves become visible.
  
  

Insecticidal Sprays

• Infestations of apple maggot, codling moth and plum curculio damage apple crops. These insects or their larvae can destroy an apple crop. Insecticides like carbaryl and esfenvalerate are typically labeled as effective against these pests but spray with caution. These chemicals can be highly toxic to bees, which are critical pollinators for apples and other fruit crops. Sometimes, insect pests can be effectively controlled with traps and mock apples.