Many of us have started preparing our vegetable garden beds for warm-season vegetables. I have added a little extra garden space this year to allow for the addition of trap crops.
The trap crop is planted with no intent on harvesting. It’s simply an attractive host plant that lures insect away from the main crop by providing a crop that is more desirable. Insects are hungrier than we are and there are a lot more of them, too, so any extra insect management tool is welcome in my garden.
Benefits of trap crops
• Reduced damage: Reducing any amount of insect damage to the main crop, especially to ripening fruit, is a great thing. Insect damage to leaves and stems decreases the productivity of the plant and means less food for us.
• Decreased use of pesticides: Using trap crops will not eliminate the need for insecticides (organic or synthetic). Damage will still occur to main crops. However, if the trap crop lures pest insects, pesticides can be used on the trap crop to control the insects or mechanical means can be used. This means fewer pesticides on the main crop, the vegetables that we are harvesting.
• Attract beneficials: Adding trap crops enhances the biodiversity of gardens. More diverse gardens (as opposed to monocultures) attract different species of beneficial insects. When the population of beneficial insects increases so does nature’s way of controlling insect pests increases. Some trap crops may attract native pollinators.
Using trap crops
The easiest way to use trap crops in smaller gardens is by perimeter planting — planting the trap crop on all four sides of the main crop. Perimeter trap cropping may catch the eye of pest insects as they start to migrate into the garden. Row or strip trap cropping are also options, but perimeter trap cropping is the most popular.
It is important to plant the trap crop at the correct time so it is mature enough when insects move in. Trap cropping does not work for all insects. Knowing which insects you are dealing with is crucial, and may determine what type of planting (perimeter, strip, row) will work best.
There are two methods for using trap crops. For example, an earlier planting of tomatoes may be used as a trap crop for the main tomato crop. Or the trap crop can be an entirely different species of plant.
Just like any other plant, keep the trap crop healthy by preparing the soil well and adhering to soil test. A dense, lush trap crop is more desirable to insects than a thin, unhealthy trap crop that makes the main crop more desirable.
Research plots have been planted and evaluated across Alabama. Blue hubbard squash has been used successfully as a trap crop to attract and retain cucumber beetles, squash vine borers and squash bugs — insects that frequently destroy home gardens. Buckwheat, sorghum, sunflowers, okra and green beans have proven successful trap crops for stink bugs and leaf footed bugs, frequent destroyers of home tomato plants. Buckwheat and sunflowers serve double duty providing areas for beneficial insects.
Once you see the pest insect on the trap crop, it is time to act. Do not wait until populations of the pest become too high. Controlling the pest on the trap crop can be accomplished by pesticides or hand removal. If you start pest control when populations are low, hand removal is not as time consuming in small backyard gardens as it might seem. For smaller gardens, it is possible to sow seeds of trap crops into large containers. The containers can be moved around the garden as you see the migration patterns of the pest.
To learn more about trap cropping and integrated pest management, sign up online at www.aces.edu by searching “IPM Communicator.” Subscription is free.