One way insects communicate with individuals of the same species is with pheromones. Pheromones are volatile chemicals released by an insect that usually can be detected only by individuals of the same species. There are a number of different types of pheromones, but the most common type is the sex pheromone. Usually the females will emit a tiny amount of a chemical that attracts the male to her and increases the likelihood of mating. Because the chemical is volatile, air currents carry it. The male detects the pheromone in the air with receptors on his antennae. He then flies upwind to find the source of the pheromone, a prospective mate. The chemical compositions of pheromones for a number of pest species have been identified and synthetic copies can be produced in the laboratory. Synthetic pheromones can be used in conjunction with traps to catch male insects.
There are a number of fruit pests that can be monitored with pheromone traps. For growers who have not used traps before, I suggest starting out by trapping for codling moth, spotted tentiform leafminer, or peachtree borers. As you gain experience with the traps and learn how they can improve your pest management practices, you may want to begin trapping for additional pests.
The proper timing for setting out pheromone traps for fruit pests are:
| Pest | Start Trapping |
|---|---|
| Redbanded leafroller | Green tip |
| Spotted tentiform leafminer | Green tip |
| Oriental fruit moth | Pink (in peaches) |
| Codling moth | Pink |
| Fruit tree leafroller | Pink |
| Lesser peachtree borer | Late April |
| Obliquebanded leafroller | Mid-May |
| Peachtree borer | Late May |
Monitoring with pheromone traps lets you know when the insect is active. This allows you to better time control practices or, in some cases, to determine if control is even necessary. If you choose to control spotted tentiform leafminers with sprays targeted at the adults, having pheromone traps will help you know when the moths are flying in large numbers. For codling moth control, we can use a combination of pheromone trap catches and degree day accumulations to better time sprays. This will be covered in more detail in the next issue of Facts for Fancy Fruit.
Listed below are some, but certainly not all, of the suppliers of pheromones and traps.
Gempler’s; P. O. Box 270; 100 Countryside Dr.; Belleville, WI 53508; 800-382-8473; www.gemplers.com
Great Lakes IPM; 10220 Church Rd., NE; Vestaburg, MI 48891-9746; 989-268-5693; www.greatlakesipm.com
Scentry Biologicals Inc.; 610 Central Ave.: Billings MT 59102; 800-735-5323; www.scentry.com
Trece Incorporated; P.O. Box 129. 1031 Industrial St.; Adair, OK; 866-785-1313; www.trece.com
Just a few notes about using pheromones. 1. It is preferable to use more than one trap for each insect pest for which you are trapping. Sometimes, for reasons we don’t entirely understand, a trap placed at a particular location may not catch many moths, which could give you misleading information. If you have two or three traps, you can be a lot more confident in the results. 2. Pay attention to how frequently the lures need to be replaced. When you replace a lure, don’t throw the old lure on the ground. If you do, it may compete with the lure in the trap and lower your trap catch. 3. If you are trapping for more than one insect, don’t handle more than one type of lure with your bare hands. You can contaminate the lure with the other pheromone and it will lose effectiveness.