How to Control Borers in Fruit Trees

Borers are the larvae of a range of different species of beetles and moths that lay their eggs on tree bark or in the surrounding soil. These larvae bore into the tree and weaken it; severe cases of infestation can quickly kill it. You should do your best to prevent infestation, rather than hope to control it once it has arrived. The Peachtree borer attacks all kinds of stone fruit trees. The dogwood borer attacks dogwoods, apples and a range of ornamentals. Two types of appletree borer and the shothole borer also exist.

Things You'll Need

• Sharp knife
• Stiff wire
• Spraying equipment
• Insecticide
• Burlap or old newspaper
• Parasitic nematodes

Instructions

1. Keep your trees in good condition. Healthy and uninjured trees are more resistant to borers. Remove decayed limbs and branches immediately and burn them or otherwise dispose of them off your property.

2. Wrap the trunks of young trees with burlap or old newspapers in May, up to the height of the lowest branch. This is not effective against all borers, but in some cases it prevents insects from laying their eggs on the bark.

3. Dig the worms out with a sharp knife and/or insert stiff wire into the holes to destroy the grubs. This may not be viable in a large orchard, but for home orchards it is among the best methods of control.

4. Consider the use of insecticides in larger orchards. Different borers require different spray regimes, but in general the aim is to time the spraying to kill the adults and the eggs. Once the larvae have emerged and penetrated the bark, it is unlikely to have any useful effect. Regulations regarding the availability of chemicals for home use are constantly changing---make sure that you choose a product that is recommended for your specific use, and follow the instructions carefully.

5. Consider the use of parasitic nematodes. These are tiny creatures which under damp conditions will seek out borers that are within a few inches and destroy them.

Tips & Warnings

• Choose varieties of trees that are well adapted to your weather conditions. Frost damage to bark makes it easier for borers to penetrate it.

• Be careful when mowing or using a string trimmer round your trees -- damage to the bark makes it much easier for borers to get in and do damage.

• If you use chemical insecticides, always follow the instructions to the letter, wear protective clothing and use any other protective devices, such as respirators, that the instructions recommend.

References

• Utah State University -- The Home Orchard Pest Management Guide
• New Mexico State University, Fruit tree pest control
• Organic Gardens, Suite 101: Borer control