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large black beetles on tree base (photo)
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Posted by buffett (My Page) on Thu, Jul 12, 07 at 1:31
| What the heck is this thing? My dogs and my toddler want to eat it and I'm keeping them at a distance in case it pinches, or stinks, or bites. I'm also wondering if it's beneficial in my yard, or a contributor to the recent death of one of the smaller sugar maples in a yard full of old ones.
There were three or four around the base of a healthy maple. They were either scuttling through the grass or hanging out motionless on the trunk of the tree, slowly moving the rather obscene appendages on their rear ends in and out.
Thanks! |
Image link: large black beetles on tree base (photo) (59 k)
Follow-Up Postings:
RE: large black beetles on tree base (photo)
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Definitely not beneficial, and likely the cause of your maple's demise. Prionus longhorn beetles bore into the roots of various plants, and when there are enough of them they can seriously weaken or kill said plants. Get rid of them before they breed, which is what the posterior appendage is for, if you hadn't already guessed.
Tucker |
RE: large black beetles on tree base (photo)
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| WHOA. Image search definitely agrees, that's my beetle. Thanks very much, Tucker. What I'm reading here and via Google is scaring me. Are these guys worth pulling out the big chemical guns for? We've avoided spraying much so far, but I'd hate to lose any of the mature trees. |
RE: large black beetles on tree base (photo)
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I'd be careful with the insecticides, but definitely kill every one of the beetles that you see. You might check with a tree service to see if there is a systemic that they can use that won't put harmful chemicals in touch with your family and pets. Good luck -
Tucker |
RE: large black beetles on tree base (photo)
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| Some of the chemicals that used to be recommended for borers were quite dangerous for people too, causing birth defects, etc. There was a big article in Reader's Digest about a particular kind a few years ago. Does anyone remember the name of it? I don't -- unfortunately, but might remember if the name was mentioned. The article was calling for a ban on it, but I don't know if the ban ever took effect. |
RE: large black beetles on tree base (photo)
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| Thanks very much, guys. Definitely borers--we went back and found a maze of tunnels in that dead tree under the bark. We spent the weekend squishing all of the big black brutes we could find. Yesterday, our tree specialist sprayed tree bases and the surrounding ground with some pyrethrin-based stuff, which he said should take care of eggs and just-hatched grubs, and persist on surfaces for at least 3 weeks barring heavy rainstorms. I hope someone will correct me if I'm wrong, but my understanding is that pyrethrin teratogenicity and carcinogenicity is low and all in all they're pretty safe for humans unless you're out inhaling the (irritating and allergenic) spray. I'm not thrilled that we've got to spray, but it looks like we have a substantial population here. I've read they've got a three year life cycle, so I guess we'll be doing this for the next two Julys. |
RE: large black beetles on tree base (photo)
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| Happy to hear you have a handle on the problem and got some help. The insecticide I mentioned was not pyrethrin based. |
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