Japanese Beetle...

Trees that age will likely put out a second flush of growth once the beetle has completed it's life cycle. However, they use up reserves that they are beginning to store for winter. After a few years of this, they may weaken to the point where they don't survive. But, you should be okay initially. I would look to get a definite ID of the insect and initiate some kind of control method to at least reduce their numbers.

I'm not familiar with a beetle that forages on the leaves. Most beetles bore into the tree and exact their damage under the bark. Trees suffering from leaf foragers have a chance if they don't get hit too hard and/or too often.

The problem with Dutch Elm Disease is that it is a fungal infection and not the direct result of foraging insects. Unfortunately, it is the insect that carries and transmits the infection.

It sounds like the tree is being attacked by the Elm Leafminer, which is the larvae of the adult Sawfly.

The japanese beetles here put a hurtin' on one of the wife's willow trees last year. They can do some damage for sure.

Japanese beetles spend most of their life as a grub in your lawn.
That's the best time to get them if you don't mind chemicals.
Unfortunately the beetles in your trees ( my grape vines and fruit trees) also come from your neighbor's lawn(s).

Those yellow beetle bag traps will catch lots of them but I don't think they really do much except show you just how many of the suckers there are.

I have a brown spotted beetle the same size that munches along side them.
They are also eating my carrot tops this year.
Fuggers really skelatonize the grape leaves

When I lived in PA they attacked my peach and nectarine fruit. I would come home from work and find them covering a piece of fruit or two. They also liked my blueberries. During the height of the their emergence I would fill a bag on my trap each day. I could spray like crazy and it wouldn't completely eliminate them. It used to really annoy me to lose some of the best fruit I've ever eaten. One thing about the yellow traps, there is a theory that they also bring some beetles in from the neighboring area, but I still would rather knock down the bag full each day then do nothing. I also had a Penn State Fruit Lab prof tell me that you can compost many insects because they have a lot of nitrogen in their bodies. One caution is to make sure they are dead before you try to compost them or you will just be returning them to the environment to do their damage. Fortunately where I live now the winters are too cold for them to survive!

Japanese beetles absolutely love American Elms. I had planted a small American ELm in my yard and it was covered every summer about this time with Japanese Beetles and they would strip any new growth bare. They preferred this tree to nearly anything else in my yard. I dug the elm up and gave it away to friends, and I don't know whether this problem is particular to my area or not.

Sometimes, trees are more susceptible to certain pests due to deficiencies in the soil, such as a lack of trace elements. I had an insect problem on some Pin Cherry trees, and I amended the soil with some iron, zinc, and greensand (contains lots of trace minerals), and this year I had no problem whatsoever apart from an initial infestation that was quickly repelled by the tree with no intervention from me. I give my forester father-in-law the credit for that idea. So maybe just get a bag of greensand and dig it into the soil around the elm tree and see what happens.

Wingman said:

I noticed the other day that the leaves were falling off one of my many American elms. Upon further inspection, the leaves had been so called skeletonized. Upon further, further inspection, here is this black and green beetle devouring two of my trees. These two trees are maybe 20-30 years old and are of good height and shade for my house. I don't want to turn them in to firewood yet, but will these trees survive this munchfest?
Two older trees at the end of my driveway are holding up but seem to be slowly dying from elm disease, says the the tree guy who cut down some trees for me a while back.

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Black and green beetle? That's not a Japanese Beetle. Don't know what it is, but JBs are shiny copper colored, and they're not capable of skeletonizing a basil plant, never mind the leaves of an entire tree, even in pretty large numbers.

I think you ought to catch a couple of those beetles, see if you can identify them through stuff on the Internet, and if not, send them off to your state or county extension service for ID.

Also, it's easy to be led astray by seeing a critter near the scene of the crime and jumping to the conclusion that it's the one that did the damage. The beetles may be entirely coincidental, or attracted to the tree because it's been damaged by something else.

For instance, did you happen to see innocent-looking green inchworms anywhere around those trees this spring? Winter Moth caterpillars can strip a tree's canopy bare in no time flat.

Uper said:

When I lived in PA they attacked my peach and nectarine fruit. I would come home from work and find them covering a piece of fruit or two. They also liked my blueberries. During the height of the their emergence I would fill a bag on my trap each day. I could spray like crazy and it wouldn't completely eliminate them. It used to really annoy me to lose some of the best fruit I've ever eaten. One thing about the yellow traps, there is a theory that they also bring some beetles in from the neighboring area, but I still would rather knock down the bag full each day then do nothing. I also had a Penn State Fruit Lab prof tell me that you can compost many insects because they have a lot of nitrogen in their bodies. One caution is to make sure they are dead before you try to compost them or you will just be returning them to the environment to do their damage. Fortunately where I live now the winters are too cold for them to survive!

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From everything I've heard and read, those JB traps mainly just attract every beetle for several miles around into your yard and don't actually reduce the beetle population you have.

I had a huge infestation of them the first summer in my new house, and I doggedly and relentlessly went around and picked them off into a jar of soapy water to drown. I made three, sometimes four circuits of the yard a day. Next year, there were a lot fewer. Year after that, fewer still. This year, they're no more than a minor nuisance, and I only rarely find the grubs in the soil when I dig something, whereas the first year those disgusting fat white grubs were everywhere.

Wingman, I sure can't see JB in that pic, but a dead, bleach-soaked beetle may not look the same. I catch mine in soapy water, and when I go to empty the jar every few days, the corpses are still quite shiny and coppery colored.

But in any case, whether you've got JBs on that tree or something else, there's a very strong likelihood they're there because the tree has been badly injured/diseased for some other reason. JBs (and other bugs) are strongly drawn to weak and unhealthy plants. I've seen that over and over in my own garden, from one sickly basil plant in the middle of a bunch of healthy ones to an apple tree that was fatally damaged by a microburst.

If a mass of JBs are concentrated on one plant, it's almost certain that there's something wrong with that plant to begin with to make them concentrate on it.

If you really want to find out what's wrong with your trees and whether it can be treated, you need to get up there and collect some leaves and a few of those beetles and send them off to somebody who can diagnose the problem. Even if the original agent is long gone, the people who study such things can tell a great deal by the pattern of damage to the leaves.

Your best bet is to call your state or county extension service for advice on what to do and where to send samples.

I don't mean to put myself out there as a JB expert, but I've had a great deal of experience with them these last four years and have done an awful lot of reading up on them.

Definitely looks like Japanese beetle to me.


My wife has a young willow tree about 15 ft tall and they pretty much skeletonized it last July.

Those are Japanese Beetles for sure, no question about it.

I would get a five pound bag of greensand and dig it into the soil around the elm tree and water it really well. Greensand is loaded with trace elements. If the tree is missing some trace elements, this will supply it and possibly fend off the beetle attack. No guarantee, but trees that are stressed or lacking essential nutrients will have a problem fighting off insect attacks.

Bag A Bug, Home Depot , five bucks, works great..

hey wingman, you got japanese beetles. They can strip a tree, but normally a tree can survive a stripping and still be fine. This is true for almost all deciduous trees. A few of the evergreens cannot survive being stripped of needles (hemlocks, for example, often die after one stripping by gypsy moths. you gotta have a pretty severe gypsy moth problem before they strip the hemlocks). The japanese beetle peak doesn't last all summer, and I'd expect a healthy elm to put out new leaves after the beetles ease up. If the trees are otherwise OK, I think they'll be fine.

I spray my ornamentals with liquid sevin in a hose end sprayer. Every year just before the 4th of July is the outbreak for jap beetles here in michigan. The sevin "stays" on the leaves for awhile, just long enough to get past the "outbreak". They also seem to like darker colored leaves. The sevin works good for me. KD

I haven't had much luck with Sevin, but I've used the powder.
I've tried fruit tree spray that's supposed to get them, but man miss one leave and they pig pile there.
I never find dead ones on the ground.


Went looking for replacement attractant for last year's bag a bugs and couldn't find any.
Took the traps out of storage anyway and the plastic box was full of oriental beetles.
Hung them up with the old attractants anyway and got about a hundred in one bag in less than half a day.
Now I wish I had put the little round attractant thingies in plastic bags, but damn the attractants from last year still work.
Mostly oriental beetles in the bags, though.

Went back to Lowes to get a couple new ones and they were completely sold out the very next day.
Must be crawling out of the ground everywhere here.

Dad used to have me walk around and spray the Japanese Beetles with soapy water, I didn't watch to see if it was very effective, but we never lost any trees or bushes. For Gypsy Moths I was partial to WD40 and a lighter.

I hates them Japanese Beetles. They can cling to you like its nobody's business. Tenacious little buggers. Too bad they are so naughty, cuz they have a fantastic color scheme.