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cateyanne

cucmber beetle or bean leaf beetle?

19 years ago

I have just noticed my bean leaves are being devoured. I found a few tiny beetles on the leaves and while looking up the culprit cannot figure out if it is a spotted cucumber beetle or a bean leaf beetle. It was very tiny and a pale yellowish tan with dark spots on it's back wing covers and a black head. i do have cukes in the garden if this matters, but so far I've gotten a good first crop from the cukes and I don't see any damage to them. beans are another story they were planted late and are not growing really well. I want to stop the destruction pronto but don't know exactly what I'm dealing with here. can anyone help? do these two beetles look a lot alike in person? they sure do in pictures. what is the method to get rid of them?

Comments (5)

  • 19 years ago

    I've had bean leaf beetles. They can be a real pain. They come in a variety of colors, from yellowish to deep red/brown. They can be distinguished from cuke beetles. Bean leafers have a stripe on the outer edge of their wing covers, but cuke beetles don't.

    I found that spraying the beans with Neem (top and bottom sides of the leaves) worked very well against bean leaf beetles. Earlier this summer I was catching and killing a dozen or more every morning, then I sprayed a couple times a week or so apart, and now I'm down to just the occasional beetle.

    Good luck.

    Here is a link that might be useful: bean leaf beetles

  • 19 years ago

    you're right. i googled a bit more, went out and captured a few specimens and what I have is the bean leaf beetle. I found it in a few of it's stages: yellow no spots, yellow with spots and red with spots. It is totally destroying one grouping of plants and is on to another grouping. i covered my bean groupings, which I have staked, with very fine wire fencing to keep the rabbits from eating them. Solved that problem, now on to the next one-beetles! I have never used pesticides of any kind so am unfamiliar with them and what they do (esp. to neighbor vegetable plants and the produce from all of them. What is neem and what will it do - besides of course kill the beetles?
    If I pull out the beans will these beetles attack any other of my plantings? I have tomatoes, cucumbers, peppers and Indian corn. Just wondering. Thanks!

  • 19 years ago

    I don't know if bean leaf beetles will attack anything else. I've only ever seen them on beans.

    Neem is a botanical spray. It is very safe as these things go. For use on food crops, it says it can be used up to the day of harvest. It's approved by OMRI for organic use. The one major caution is that you should not use it at a time when bees are active in an area, as it will kill them if they are directly sprayed with it. Delay spraying until early evening, when the bees aren't around.

    This is mostly from E. Smith's Vegetable Gardener's Bible, (paraphrased), about Neem:

    "Neem is made from the seeds of the Neem tree, which is found in southern Africa, India, Australia, and SE Asia. The active ingredient, Azadirachtin, blocks the progression of the insect's life cycle, so insects don't die right away. But Azadirachtin also acts as an appetite suppressant. After eating a little of a sprayed plant, the bug just stops eating, and in a few days it dies."

    Neem also fights a variety of diseases, like powdery mildew, anthracnose, etc.

    Below is a link to a GW discussion of Neem (which seems to have gotten side-tracked into what Neem smells like), and there are lots of other discussions of it. Do a search if you want to see others' opinions on it.

    Good luck. Last year the beetles devastated my pole beans (I didn't try neem last year). They even nibbled the beans themselves, so that a lot of my beans had little scars, which I had to trim off before cooking them. What a pain! I hope you find some way to combat the beetles without having to pull out your plants. Fresh beans are so nice.

    Here is a link that might be useful: GW discussion of Neem

  • 18 years ago

    Found some bean leaf beetles today as well on some pole beans which are on my south wall of the house. I saw minor damage on what now is now towering pole beans but did not know what it was until I saw them on the leaves. I guessed right on what to do and swiped them into soapy water before I researched them. Sure enough it was between 12 and 4.
    The survivors had the gall to try and move 50 feet away to bush beans and newer pristine pole beans after I took down most of them. In all I got 12 of them and have not been able to find more as yet today. It looks like manual removal should suffice for now but will look into picking up some Neem perhaps.

  • 10 years ago

    I have spotted a couple of these for the past couple of weeks. But, today when I was outside also doing my routine japanese beetle check, I found about half a dozen in one area. I have sprayed my plants down with neem, but they don't seem to care... they're still hanging around. grrrrrr!