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Unfortunately, worm-free apples don’t come easily

SUSAN MULVIHILL/SPECIAL TO THE SPOKESMAN-REVIEW This McIntosh apple has been covered with an apple maggot barrier. (Susan Mulvihill / The Spokesman-Review)
SUSAN MULVIHILL/SPECIAL TO THE SPOKESMAN-REVIEW This McIntosh apple has been covered with an apple maggot barrier. (Susan Mulvihill / The Spokesman-Review)

By the time you finish reading this, you will discover the lengths I am willing to go to in order to enjoy homegrown worm-free, pesticide-free apples.

I am an organic gardener through and through. I refuse to use pesticides. But when it comes to our small orchard, I also refuse to neglect it, which would cause problems for other folks in the area who are also trying to grow tree fruit.

This has required research and experimentation over the past three years but my husband Bill and I feel like we’re onto something.

The primary apple pest in this region is the codling moth. During the spring and summer, the moths lay eggs on apple tree leaves or the apples. When the larvae hatch, they burrow into the center of the apples to feed on the nutrient-rich seeds.

We start by hanging a codling moth trap in our orchard. These paper traps contain a pheromone (mating hormone) lure and are lined with a sticky substance. The moths are attracted to the pheromone and get caught.

We monitor the traps frequently and once we see moths in the traps, we know it’s time to act.

Three years ago, we started hearing about apple maggot barriers, which look like the little nylon “footies” ladies slip on their feet when trying on shoes at stores.

These barriers are placed over the developing apples in the spring when they are about the size of a marble and are supposed to prevent the moths from laying eggs on the apples.

In 2009, we slipped those barriers onto about 600 apples and were anxious to see the results. Unfortunately, about 80 percent of our apples still had worms in them that fall.

Last year, we learned about using the barriers in conjunction with a spray called “Surround At Home Crop Protectant.” This is a powdery form of kaolin clay which has the consistency of cake flour.

My husband mixes it with water in a large bucket, transfers it into a clean sprayer and sprays the apples and foliage. He first applies the spray after the apple blossoms have dropped and later if rain washes it off.

When it was time to harvest our apples last fall, we discovered about 80 percent of the apples did not have worms. What a difference.

We also noticed that we had occasionally missed covering some of the apples, but as long as they had Surround on them, the majority of them were worm-free. This has led us to wonder if perhaps only the Surround is necessary for success and we’re still experimenting with that.

In addition to the maggot barriers and Surround spray routine, we have learned some important things about successfully growing apples:

1. Keep the trees stress-free by providing them with regular water. Keep the weeds down, because weeds compete for moisture and nutrients.

2. Clean up the orchard every fall by raking up leaves and any dropped fruit. This reduces the overwintering of diseases and insects in the orchard.

3. In spring, thin the developing apples to one apple every 6 inches so the tree has enough energy to mature each one. This makes the tree more vigorous and you’ll get larger apples.

4. Monitor the trees weekly to make sure no other problems are cropping up.

I know all of this sounds very time-consuming but it’s worth it to ensure our food is safe to eat.

Susan Mulvihill can be reached via email at Visit her blog at for more gardening tips and information.


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