This summer, be on watch for these two pests in the Southwestern states.
There are numerous varieties of harlequin bug, including invasive species like the Bagrada bug. Hailing originally from Africa, Bagrada hilaris was first cited in the U.S. in 2008 and has since spread across southern California and Arizona. More common in this part of the world is Murgantia histrionica, commonly referred to as simply the harlequin bug.
A member of the stinkbug family, harlequin bugs are notable for their brightly marked, shield-shaped bodies bodies. They feed mostly on vegetables of the mustard or cabbage family, including Brussels sprouts, cauliflower and radish, but may also be found enjoying beans, eggplant, potatoes and tomatoes.
Because of its motley coloration, the harlequin bug is easy to spot and handpick. When you’ve identified and dealt with the adults, be sure to look for and destroy any nearby clutches of young, usually a dozen black-and-white keg-shaped eggs.
Actually a caterpillar, this garden pest prepares for its eventual metamorphosis into a moth by feeding on plants from the nightshade family. That may include your tomatoes, eggplant, peppers or potatoes. Hornworms also routinely ignore the warnings of the surgeon general, so if you grow tobacco, those plants may also be at risk.
Though often mistaken for one another, there are actually two varieties of hornworm to watch out for. Both are green and can grow up to four inches in length. One, the tomato hornworm (Manduca quinquemaculata), sports a blue-black horn and V-shaped markings along its back. The tobacco hornworm (Manduca sexta), meanwhile, is distinguished by a red horn and seven diagonal lines along its sides. Both can be difficult to spot nestled among the greenery of your garden, and both can be destructive to vegetables, so keep a close eye out for any damage to the leaves or stems of your plants.
Hornworms are generally large enough to hand pick and destroy. Planting marigolds around your vegetables may also help deter hornworms from invading. Certain species of parasitic wasps will prey on hornworms, taking care of the problem for you—provided that you don’t consider wasps a bigger problem. If more stringent measures are needed, you can use bacillus thuringiensis. At the end of the season, be sure to till the bed to turn up any pupae that might be lurking there in anticipation of next season.