Questions on: Beans Ron Smith, Horticulturist, NDSU Extension Service

Q: Bean beetles decimated my bean crop last year. I read that purple string beans are distasteful to these pests. Will the beetles stay away if I plant some purple string beans in with my yellow and green beans? (e-mail reference)

A: I don’t know. It depends on how smart the bean beetles are! It would have some sort of sequestering effect, but how much is difficult to say. The best thing you can do is some inter-cropping (I assume you are writing as a gardener) with an entirely different species of vegetable and practice crop rotation.

Q: I grew green beans (bush variety) this summer. The first picking was good. After that the blooms would start to form and then disappear. I have been told that I had soybean beetles. If it is true, are they in the soil? Should I work insecticide into the soil now or in the spring? What should I use next summer so this does not happen again? Thanks. (Mina, S.D.)

A: I am loath to recommend any insecticide at this time of year. I would suggest rotating the planting site with something not related to beans and then monitor next spring for any beetle activity. If you find some activity, spray with the least toxic, environmentally friendly material available.

Q: For the last two years our peas and string beans have failed to come up. We have very sandy soil. Over the years I have tilled in most of the leaves from the trees in our yard.plus the fall grass clippings. I apply 10-10-10 fertilizer each spring before the last tilling. What am I doing wrong? (Wadena Minn.)

A: My best guess is that you have some herbicide residue in the grass clippings that is acting as a pre-emergent herbicide. Some herbicides have good residual even when composted.

Q: Enclosed is a bean pod with two beans in it. Could you tell me what kind of a bean they are, and if they are edible? (Moorhead, Minn.)

A: Any seed received in the mail that is unlabeled should never be used as food. The sample you sent was for ornamental purposes only, not for consumption. You are fortunate that you did not ingest enough to make yourself sick.

Please take care!

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