The No. 1 problem in vegetable production in the Southeastern United States is insect pests, according to Ayanava Majumdar, Auburn University Extension entomologist and the state coordinator for Sustainable Agriculture Research and Education.

Caterpillar pests of vegetables have long been the major issue for vegetable producers, he says, including diamondback moths, squash vine borers, hornworms and armyworms. “Those insects can cause 100-percent crop loss if control measures are not taken. Sucking insect pests such as stink bugs and leaf-footed bugs also are emerging problems in vegetable production. Stink bugs typically become a problem in mid- to late-season and heavy infestations may cause fruit and flower drop, affecting plant yield, says Majumdar.

It can be difficult, he says, to manage caterpillars and stink bugs with currently available general-use pesticides that may give rise to insecticide resistance and cause non-target effects. “An alternative method to combat insect pests is by the use of trap crops,” says the entomologist.

A trap crop is an attractive host plant that attracts insects away from the main crop during a critical time period. “The basic principle of trap cropping is that insects have a preference for host plants and will move to a preferred host if given a choice. Insects are highly attracted to reproductive stages of host plants over the vegetative stages and trap cropping uses this attraction to good use,” he explains.

Generally, the trap crop is considered “sacrificial” because it protects the valuable main crop when pest populations exceed normal levels. The target insect must be controlled in the trap crop with timely insecticidal applications or by mechanical removal.

Since the 1930s, says Majumdar, there have been many reported cases of successful trap cropping for management of various insect pests resulting in great reduction in the use of pesticides.

“The benefits of trap cropping include reduced dependence on insecticides, the low cost of trap crop seed, conservation of natural enemies, and better crop and environmental quality. But remember, trap cropping is not a silver bullet solution to all of our pest problems because it does require more pest management skills and the knowledge of insect behavior. Also, not all insects can be controlled with trap crops,” he says.

There are two ways you can use trap cropping, says Majumdar. One may be to use the same plant cultivar as a main crop and a trap crop. The trap crop is planted much earlier than the main crop in order to serve as food for the insects.