Apple Maggot Pest Control

WHEN I CUT OPEN MY APPLES I FIND BROWN LINES THROUGHOUT THE APPLE. WHAT CAUSES THIS?

These symptoms are typical of apple maggot which is becoming a serious pest of "backyard" apples here in the Pacific Northwest. Apple maggot was first detected in Portland, Oregon in 1979.

It is an insect native to eastern North America where it used to feed on hawthorn fruit until European colonists Introduced the domestic apple tree to North America. It has since spread to many varieties of apples.

WHEN & HOW DOES THE APPLE MAGGOT INFEST THE APPLE?

Adult flies start emerging from the soil in June and begin infesting fruit soon after. Newly emerged adults go into the canopy of the tree to feed on honeydew and other sweet substances.

Seven to ten days after emerging the flies mate and the adult female fly makes a small puncture wound in the fruit and inserts an egg just below the skin. This damage is often overlooked, but leads to the fruit dimpling around the wound.

The eggs hatch in 2 to 10 days and the larvae tunnel through the apple meat leaving brown streaks. This is only visible when the apple is cut open and can ruin the taste and appearance of the fruit.

If tunnels are extensive the fruit may be too damaged to use at all. Once the larva matures, usually in 20-30 days, it then leaves the fruit, drops to the ground where it pupates and over-winters in the soil.

WHAT CAN BE DONE TO PREVENT APPLE MAGGOTS?

Control of this pest is difficult. One possible treatment is a clay based protectant called "Surround at Home" that can be effective. It is not an insecticide; it works as a barrier film that irritates flies and disguises the host, discouraging egg laying.

It should be applied in late June and reapplied every 7 to 14 days, or more if it rains. Be sure to read the label and follow directions.

CAN YOU TREAT OUR TREES FOR US?

Yes, we can tailor a treatment program for you that will help reduce infestation.