Manage caterpillars in your garden: 10 strategies to keep your plants healthy

WEST LAFAYETTE, Ind. — Insects can wreak havoc on kale, broccoli and other cruciferous crops.

“Key insect culprits are caterpillars, flea beetles and thrips,” said Elizabeth Long, assistant professor of entomology at Purdue University, during the Purdue Extension Vegetable Farming Webinar series.

“Caterpillars are the primary pests to manage on cruciferous crops. If you don’t stay ahead of the, they can devastate your crop.”

Caterpillars feed on leaves and heads of developing crucifer plants, causing reduced plant growth, large feeding holes and lots of droppings that may stain produce.

Control Strategies

1. Plant varieties that are less sensitive or susceptible to insect damage.

2. Consider plant timing to avoid periods of high pest activity. For example, planting early allows seedlings to grow out of the vulnerable stage before flea beetles become active.

3. Avoid planting the same crop in the same field year after year. Rotate crops. This slows the build-up of pest insect populations, especially flea beetles.

4. Disk crop residue and maintain good weed control. This interrupts the life cycle and limits important non-crop food sources for pest insects.

5. Preserve and protect natural enemies.

6. Use reduced risk or organic insecticides that are less toxic to parasites and predators.

7. Apply insecticides based on scouting and monitoring efforts and pest thresholds.

8. Caterpillars are typically the most important insect pest to manage. Select insecticides will manage caterpillars and other insect pests, too.

9. Apply products in sufficient volumes of water and achieve good coverage to get the best efficacy from insecticide applications.

10. Focus insecticides on vulnerable and marketable part of the crop. Apply insecticides judiciously.

In A Nutshell

• Look for key signs and symptoms of insect pests. Examples include appearance of damage, size of feeding holes and presence of frass.

• Scout, monitor and use cultural strategies to reduce favorable habitat, presence of weedy hosts and buildup of pest populations in your crop fields.