It’s the striped cucumber beetle, a particularly nasty pest because it can transmit bacterial diseases that cause plants to wilt and die. At first, I was picking at least 10 beetles with my tweezers every time I went out, and now I’m getting only a couple. I’ve gotten double kills sometimes, as I interrupt two beetles in the process of making more beetles. I like to think I’m disrupting their life cycles (it sure seems like I’ve killed every cucumber beetle in the neighborhood), but then I remember that the females of the species can lay as many as 1,500 eggs at a time.
Zapping the beetles when they’re in zucchini flowers is easy because there’s no place for them to hide when my tweezers come calling. The zucchini plants are almost like a “trap crop,” or something planted specifically to attract a pest you’re trying to get rid of. Beetles in cucumber flowers present more of a challenge, because there are so many flowers to check and the beetles have an easier time flying away because the flowers are small. I often place my hand under the flower and then shake it to make the beetle to fall.
When I use tweezers, the metal vise is enough to dispatch the beetles. When I catch them in my palm, I cut them in two with my thumbnail.
But for all my effort, I’m thinking that hand-picking is too little, too late. I expect that our lovely cucumber plants will be wilting and dying in a few weeks because of these beetles. They have every year in the past. So I’ve done some research and come up with some strategies for next year.
Late this fall, I plan to till the garden in the evening to expose the overwintering beetles to freezing temperatures. I will put repellent plants, such as calendula and radish, near the zucchini and cukes. I already use row covers, those fabrics that let in sun and water but exclude bugs, but next year I plan to leave them on longer, removing them for only a few morning hours to let in pollinators. I delayed planting this year to try to miss the beetles’ prime time, and next year I may delay longer.
There are lots of other techniques that organic gardeners use. Some people plant trap crops that the beetles love, such as Blue Hubbard squash and Big Max pumpkins. Some put aluminum foil all around the stem of the plant, or create traps using pieces of wood painted yellow and smeared with a sticky substance. Some spray the plants with kaolin clay or create a bat habitat.
I have to stop now because it’s time to go outside again and kill more cucumber beetles.