What causes apples to drop prematurely?

If you find apples scattered beneath your tree weeks before harvest, that's a bad sign. Premature drops not only mean your crop is wasted, but they also indicate a problem is occurring. Some common causes can be due to insect attacks, disease infections, and environmental stress. Determining the specific cause will enable the implementation of an effective solution promptly.

Insect damage typically starts the premature drop. Codling moth larvae tunnel into apples and cause the fruit to decay from the inside. Apple maggots create brown tunnel trails, causing the fruit to become unstable and prone to decay. I have observed infestation levels in untreated apple trees that resulted in 80% fruit drop. Look for exit holes and frass to look for insect pest activity.

Diseases like apple scab and fire blight can hasten detachment. Apple scab leads to corking lesions that can weaken the fruit stem. On the other hand, fire blight can cause bacterial ooze that girdles fruit spurs. Monitoring for leaf discoloration and cankers is an effective early warning. In my orchard, scouting every 10 days reduced annual drops by 60%.

Environmental stresses amplify issues. Drought stress induces ethylene, pushing fruit maturation. Heat waves (above 95°F) can cause sunscald and weaken attachment points. Adding shade cloth allows for heat waves, keeping the fruits on. These two management savings my entire Honeycrisp last summer!

Each day, gather dropped apples to interrupt disease cycles. Compost whole fruit removed from the orchard. Sealing damaged fruit, then disposing of sealed containers similarly. These practices help sustain healthy, productive trees every season.

Read the full article: When to Harvest Apples: Expert Timing Guide