Although the peach tree borer is the insect that most peach growers are concerned with in peach trees, the trees may also be affected by scale, curculio, bagworms and a host of other insects. One of the most reliable methods of insect control on peaches is to use preventative sprays, pesticides and horticultural oils. There are also a wide variety of cultural practices that will help cut down on the number of insects that attack a peach tree.
Contact your local county extension service to ask them which insects they predict will be a problem to peach trees this growing season. Your county extension service can draw on resources with the USDA and your local agricultural college to track insect migration, breeding and growing patterns to predict which insects will be a problem. It can also recommend a schedule for administering chemicals to repel insects from peach trees.
Clear away all debris and vegetation--including leaves, twigs and weeds--from around the base of your tree with a rake. Debris provides a breeding and hiding location for catfacing insects such as stink bug. According to Texas A&M University, catfacing insects are insects that feed on fruit and give it a gnarled, distorted appearance called "catfacing."
Plan a schedule of applications for preventative pesticides that targets the most probable of the insects that will attack your peach trees. In general, you should plan to administer trunk sprays of an insecticide designed to kill the eggs and larvae of peach tree borers two weeks apart during the egg laying season. The egg laying season varies throughout the United States. In Colorado, this may occur during the middle of the peach growing season. Scale insects should be treated in early spring, before the tree sets buds, with an application of horticulture oil. Mites can be controlled with a spray of an approved miticide.
Spray the ground beneath peach trees with a liquid application of predator nematodes mixed with water. Predator nematodes attack the larvae of peach borers to kill the larvae and reduce the population of borers. Use of predator nematodes has been inconsistent in keeping the population of peach borers reduced. Only use predator nematodes if the temperature climbs above 50 degrees F.
Place a ring of Paradichlorobenzene (PDB) moth crystals around the tree in a band that is 1 to 2 inches away from the trunk. Do not allow the PDB crystals to touch the trunk. The crystals will act as a fumigant to remove peach tree boring larvae that have already burrowed into your peach tree. The crystals should not be applied if the temperature is below 60 degrees outside.