Ask a Master Gardener: BOLO: Bad Bugs in the Vegetable Garden
- Jennifer McDonald
- Apr 5
- 3 min read
By: Mary Townsley, Mobile County Master Gardener
This is the time of year home gardeners begin to plant their vegetable gardens, dreaming of tasty produce to come and hoping to come out winners in the annual battle of "The Gardener vs. The Bad Bugs"...
Keep in mind that there are many beneficial insects that lend their skills in our gardens, so knowing which bugs are the Bad Bugs is key. Unfortunately, there is only room in this column to focus on a few of the most common insects wreaking havoc in our gardens.
Hornworms, the larval stage of sphinx moths, feed on tomatoes and other nightshades, such as eggplants, peppers and potatoes. But note that those big green hornworms (up to 4.5" in length) systematically chewing up your tomato plants, leaves, stems, flowers and fruit, are most likely tobacco hornworms! They have a series of diagonal white stripes on their sides and a tomato-colored horn in their rear. They eat a lot: two hornworms can decimate a good-sized tomato plant!! Hornworms are not harmful to humans: handpicking and discarding in soapy water is a good method for control. Or you can feed them to your chickens!
Squash bugs have piercing/sucking mouth parts and feed on cucurbits: squash and sometimes melons. Heavy feeding can cause plants to wilt and die. While organic management is difficult in larger gardens, regular scouting and hand-picking of squash bugs and their eggs can be helpful if you only have a few plants. Since they like to hide under mulch and other weed barriers, check under these as you are scouting to look for the adults.
Mexican bean beetles are related to ladybugs, but feed on the leaves of legumes: bush and pole beans, lima beans and sometimes cowpeas, rather than aphids. Adult Mexican bean beetles have 16 black spots on their copper-colored backs and lay their orange-yellow eggs in large clusters on the undersides of leaves. Destroying garden debris where adult beetles overwinter can help in minimizing beetle numbers. You might consider delaying planting beans, as beetles emerging from their overwintering sites feed voraciously.
Leaf-footed bugs are piercing/sucking insects related to stink bugs. They feed on a variety of vegetable and fruit crops: tomatoes, cucumbers and squash are common targets in the vegetable garden. Their feeding behavior leaves ripening vegetables subject to secondary disease and rot. Look for clusters of adults or nymphs and the golden-brown eggs laid like logs end-to-end in a row on the underside of leaves or on stems. Wear gloves when you handpick leaf-footed bugs, as they can be stinky, and drop them into soapy water. Handpicking and good cultural practices to limit overwintering of adults can help control the leaf-footed bug population.
You may also see aphids and cutworms (or at least evidence of cutworm activity). Aphids feed on young shoots of cole crops such as broccoli and cauliflower, beans, peas, tomatoes. Encourage ladybugs to inhabit your gardens, as they like to munch on aphids. With small clusters, you can wash them off with a water spray. Cutworm larvae do exactly what the name implies: they chew on and cut off stems of young plants near the soil level. No more plant...
Cultural controls are important first steps. Space plants well, remove debris, and water appropriately to keep your plants healthy and minimize stress. Scout your plants regularly and hand pick the Bad Bugs. Remember control is easier when bugs are small. Row covers can limit access for flying insect pests and thus limit egg laying on your plants, although they also limit access for important pollinators.
For a more extensive overview of Bad Bugs in the vegetable garden and other management strategies, refer to this article at the Alabama Cooperative Extension blog:
Remember your local Cooperative Extension office is available to help identify pests and diseases in your vegetable garden (251-574-8445). Or call the Master Gardener Helpline toll-free at 1-877-252-GROW (4769).
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