Answer: These black and orange pests lays distinctive eggs which resemble neat rows of tiny white barrels with black hoops. Both the adults and the nymphs suck plant sap and can kill a plant by their voracious feeding. They make their presence known by yellowish patches on plant leaves.
The adults overwinter in plant debris. In the spring, the female begins laying eggs on the undersides of leaves. Generally there are 3 or 4 generations in a summer, so if you begin controls early you can minimize problems later in the season. The first step in controlling harlequin bugs is to carefully clean up all the plant debris in your garden at the end of the growing season, and discard it.
Here are some other steps you can take: Handpick them when they first appear in the spring, and squish any eggs you find. Use row covers. (You'll need to remove the covers when the squash begin flowering so pollinators can reach them.) Bait them with cabbage leaves (which they love) elsewhere in the garden, checking the "traps" daily and destroying any bugs you find. Repeated insecticidal soaps spray can be effective.
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