Regional Gardening Reports :: National Gardening Association

In the Garden:
Northern & Central Midwest
May, 2007
Regional Report

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This white powdery coating is kaolin clay, which is sprayed on fruit trees to protect them from feeding insects.

Growing Fruits Without Chemicals

There's nothing quite like fresh fruits from your own garden to make the summer extra special. But have you always been afraid to grow them because of an assumed need for chemical pest controls? It is possible to grow fruits without chemical pesticides, but you need to make a commitment to a little more time in the garden, especially for observation.

The first step is to choose fruits that are more carefree than others. Apples are, by nature, a needy crop, but you can easily grow Asian and other types of pears without much thought to pest control. Currants and gooseberries are also fairly carefree, as are raspberries and blackberries. Grapes are needy. Peaches need more care than apricots.

This doesn't mean that you can't grow the other fruits, just that you will need to be ready with nonchemical types of controls. And remember that timing is everything.

The Organic Fruit-Grower's Arsenal
Three essential tools for the organic arsenal are horticultural oil, insecticidal soap, and Bacillus thuringiensis (Bt), an organic bacterial control for caterpillars. There are also other controls such as lime-sulfur spray, baking soda, and compost teas, all of which control fungus. A terrific new product that is showing promise for controlling pests is kaolin clay. This fine clay is mixed in water and sprayed onto the developing fruits at 7- to 14-day intervals in the early growing season. It coats the fruit, making it unpalatable to insects. It's harmless and washes off for eating.

The main pests of apples include codling moths, apple maggots, plum curculio, and apple scab. If you select scab-resistant varieties to plant like 'Jon-a-free' and 'Liberty', you've already taken care of one problem. Codling moths can often be controlled in small trees with pheromone traps and Bt. Apple maggots are controllable by using red sphere traps coated with Tanglefoot.

Plum curculios are hard to control, but they have a wonderful habit of playing dead and dropping out of the tree. Early in the morning, place a sheet beneath the tree. Shake the tree and gather up and destroy all the weevils.

The lovely metallic blue flea beetle is a real problem for grape growers since it feeds on the new buds as they open and then again feeds on the fruit. Kaolin clay is somewhat effective as is the old-fashioned squashing method. Get into the garden early in the morning when they are sluggish, and hand-pick the beetles and squash them.

Grapes are also susceptible fungus diseases of one sort or another, but there are resistant varieties available. Lime sulfur spray will handle most other problems.

Plum curculio is an issue (see "Apples" above for controls) as are many fungal diseases as well as peach tree borers. Borers lay eggs under the bark and the larvae tunnel into the plant. They don't harm the fruit but can girdle and kill the tree. If you see sap oozing or sawdust near a small hole, insert a paper clip or wire to try and kill the borer.

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