Japanese beetle invasion - threat to bonsai ?

davetree

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I was in my bonsai garden last night when I noticed that several of my grape vines were swarming with Japanese beetles. Are these a threat to my bonsai ? The beetles have chewed many holes in the grape leaves but I couldn't find any or any problems with my trees. Anyone have any experience with Japanese beetles ?
 

rockm

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Yeah. They can be. If they find a tree they like. I've had them on and off on some of my trees--they seem to like zelkova and a couple of others. I've never had an infestation, but one attracts a few dozen more. Damage is usually limited to a few leaves that are eaten -leaving the leaf veins...
 

davetree

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Thanks, I will be spraying them with oil tonight, there has to be a few thousand of them.
 

jk_lewis

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I doubt that oil will bother them much. But the damage they cause is purely cosmetic. Your trees will grow new leaves.

On my shelves, they seem to like crape myrtle quite well -- and anything in the rose family.
 

rockm

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Rose family inlcudes apples and crab apples...Spraying does little good.

It used to be that people would set traps baited with rose hips to attact the damn things. However, they found that the traps actually cause more problems, since the beetles that were attracted to them are a lot of stuff NEAR the traps before they entered.

Not much you can really do about them. They are a scourge...
 

Chub

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They or at least the one I caught in the act liked my azalea. Was curious about what was doing some major chomping on one set of leaves. Could never find anything. So I took a flashlight and did a little night time investigation. And there it was, having a feast.
 

davetree

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Well, lucky for me, I guess. I have no zelkova, crape myrtle, azalea, apples, crabapples, nor birch. I do have maples, Chinese elm, pines, junipers, and a few others. So far, not one bonsai leaf has been touched.
 

Chub

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Well, lucky for me, I guess. I have no zelkova, crape myrtle, azalea, apples, crabapples, nor birch. I do have maples, Chinese elm, pines, junipers, and a few others. So far, not one bonsai leaf has been touched.

Now you do know you just put the mush on yourself don't ya..lol.. Bonus question. What movie was being "mushed" mentioned in?
 

Michael T

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They show up every season in my garden to pick on a few particular trees I have. This year it was a birch.

Every year I do the same thing, I find a powder bug killer that's rated to kill beetles and I sprinkle it all over the leaves. Ends the problem every year before it ever gets started.
 

Mike423

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They show up every season in my garden to pick on a few particular trees I have. This year it was a birch.

Every year I do the same thing, I find a powder bug killer that's rated to kill beetles and I sprinkle it all over the leaves. Ends the problem every year before it ever gets started.

That sound like an idea, I've tried Neem oil and they just seem to laugh at me. I can never have any roses without cutting/bringing them in (if it gets that far) since they decimate them from late July to late Aug. So far they have pretty much left my trees alone though hope it stays that way, knock on wood, pun intended.

DEATH TO ALL JAPANESE BEETLES
 

sean f

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i use Seven for japanese beetles works great
 
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I used to do gardening work for a guy that insisted on setting up those pheromone traps. I finally got the courage to tell him that some studies suggest that the traps make the problem worse by bringing more beetles into the area. He said he was aware of the studies and thought they were very credible. When he noticed my perplexed look, he said that the satisfaction of dispatching several thosand beetles per bag outweighed any increase in population the traps may cause. I chuckled at his frank honesty.
 

amkhalid

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J beetles love my elms and showed up last year in my neighborhood for the first time. Don't harm the trees but make them look like hell. Oils and soaps did nothing.

This year I got an imidacloprid based systemic insecticide and it works incredibly well. Its a granular form which you just sprinkle on the soil. Couldn't be easier.

The beetles take one taste of a leaf and basically become paralyzed and drop dead. Its very satisfying to come out in the morning and see the ground around my elms littered with dead beetles.

Normally I am very reluctant to use pesticides but I am happy to kill alien invasive species. :)
 

Bill S

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I used Bayer Advance for Trees and shrubs this year, haven't seen much in the way of bugs in anything so far, used same as above, sprinkle on, water it in.
 

DannyBonsai

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I just pick them off my rose bushes (about 2 dozen per flower) and put them in a tin in a fire. grind 'em up, they make a nice bone meal substitute! Payback!
 

waltr1

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I have used Safer Soap spray on the beetles with success. It does kill them and seems to repel them for a week. So spraying the trees they like (J. quince) every week keeps them away.
 

coh

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I think the key (if you want to avoid poisons) is to have enough larger landscape plants around that they like, so they'll ignore the little trees. We have a very large porcelain berry vine on a fence and they absolutely swarm all over that but pretty much leave the bonsai alone. They are also very attracted to grapes and raspberries.

As for the traps - I've often thought the best solution would be to get all your neighbors to set up traps and NOT put any in your yard. Then all the beetles would be attracted away from your yard. Have never tested this but it seems like it might work!

Chris
 

davetree

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Update - they seem to be looking for new things to eat after decimating my grape vines. I found the beetles today on a cork bark elm. Time to get out the big guns. Will give my elms a systemic today, I'm not screwing around.
 

Bill S

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You can buy praying mantis' get a bunch and put them around your yard, from what I have seen they stay around, as do the off spring.
 

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