Trap Crops Help Combat Pests in the Garden

by Molly Jameson | May 23, 2022

Use traps crops, such as sunflowers and sorghum, to lure pests away from your crop. Photo by Molly Jameson.

To be a successful gardener, it is important to have an integrated approach to handling obstacles in the garden.

Aphids were lured into this sorghum seed head, which then attracted mealybug destroyer larvae, which are excellent garden predators. Photo by Les Harrison.

These considerations include techniques such as planting disease resistant crop varieties, maintaining proper plant spacing, planting at the appropriate time, monitoring the garden and properly identifying insects and diseases, watering uniformly, and many more cultural and preventative measures that will aid in a garden’s success.

As we transition from the relatively mild and dryer days of late spring into the hot and humid punishing days of summer, we often encounter more and more problems in our gardens.

Insects are commonly one of the main challenges we face, as warm temperatures and high humidity promote the growth and expansion of insect populations. To keep pests in check, it is important to consider all our options. If we turn too quickly to chemical controls, we will often encounter insecticidal resistance over time and our beneficial insect populations will be negatively affected.

One alternative to chemical controls to help combat destruction of our crops is by planting trap crops. Trap crops are plants you grow that the insect pest prefers for food and egg laying over the crops you grow that you plan to harvest. These trap crops attract harmful insects, luring them away from your garden veggies.

Sunflowers can attract leaf-footed bugs away from tomatoes. Hand pick and squish any that you see for better control. Photo by Molly Jameson.

One effective trap crop example, which has proven effective in research studies, is using the combination of sorghum and sunflowers to lure leaf-footed bugs away from your tomatoes. If left unchecked, large clusters of leaf-footed bugs will feed and mate on developing tomato fruit, leaving your tomatoes discolored and distasteful. For tomato growers, it is worth the effort to plant both sorghum and sunflowers about two weeks ahead of your tomato crop. The blooming heads of the sunflowers will lure the leaf-footed bugs in. Hand pick and squish both adults and nymphs off of the sunflowers to help cut back on their populations. As the sunflowers die back, sorghum heads start to emerge, giving you enough time to harvest your tomatoes while the leaf-footed bugs feed on the sorghum panicles.

Another effective trap crop example is to grow blue Hubbard squash at least two weeks ahead of cucurbit crops, such as zucchini, summer squash, or cucumbers. The blue Hubbard squash acts as the trap crop, luring cucumber beetles, squash bugs, and squash vine borers away from the crop.

Buckwheat flowers attract pollinators and predatory insects into the garden. Photo by Janis Piotrowski.

Trap crops are also a great tool for drawing in pollinators and natural predators of insect pests into your garden. For example, sweet alyssum and buckwheat flowers attract wasps and hoverflies. The wasps will lay their eggs on caterpillar pests, and when the eggs hatch, the wasp larvae eat the caterpillars as they mature. Hoverflies will lay their eggs on the leaves of the trap crops, which will hatch and feed on mealy bugs and aphids. Additionally, bees will be attracted to the trap crop flowers, introducing more and more pollinators into your garden.

When it comes to being a successful gardener, it is important to have an integrated approach. When cultural and preventative gardening techniques are combined with biological control techniques, such as trap cropping, your garden will be more resilient to pests and diseases, and you will be less reliant on chemical control methods, which should be seen as a last resort.