The beetles here seem to like my purple leaf plum and japanese maple much more. After I notice the beetles eating leaves I spray everything with something from Lowes called Triacide (I spelled that wrong). The stuff is nasty, the beetles sometimes die on the plants or just go to the neighbors. It makes me sneeze creepy bad, even through a mask, but hey, DDT and the like never hurt anyone, right? I end up using it twice a year and haven't had any plant related problems from it.

Traps which use fermones to attract beetles kinda weird me out. Something like if I don't want the drunks on the streets around my house, I won't open up bars to capture them.

You have to put the traps as far as possible in your yard from the tree. We have DR and JB's and they don't seem to like eating the DR. They go for cherry, poplar and sassifras. The DR will survive. Another thing is to treat the lawn for grubs in May before they start flying out. That is the recommended approach.

even better.....place the traps in your neighbors yard!!!

Or put the pheromone bait in the middle of a busy road?

Resin

Sorry Spruce to hear about your JB's & DR. The beetles are seriously trying my patience this yr. I don't have a DR but was considering planting one in the common area behind our backyard. If it is a JB magnet I won't be planting :~). I now take a long hard look at any potential new plantings to see if they are favorites of JB's. If so they won't get planted since we already have enough to keep them (and me) busy. My weeping larch has gone on to conifer heaven but it was a huge JB magnet much to my dismay. The crabapple, contorted filbert, parrotia persica, beech and roses, in particular, are taking quite a beating but thankfully I've never had anything completely defoliated. Since we have bluebirds (and others) nesting in our yard I refuse to spray. I hand-pick what I can reach and try to ignore the rest, knowing that they will be gone in a few weeks. We've had great luck treating grubs in our lawn with beneficial nematodes but the beetles are able to fly some distance so they still fly in from here, there and everywhere. You have my sympathy... Good luck!

Yeah, I hate to spray because of birds, etc. I keep it to a minimum.

As for treating the grass for grubs, etc.--we are mowing five acres, and are surrounded by acres and acres of hayfields. I assume that the grubs grow in the hayfields as well as our lawn--right?

I put the traps about 100 feet up wind from the most sensitive trees. Last year one of my three baldcypress trees was also completly defoliated (I watered it all late summer and fall and it grew back a lot of foliage and seems OK now), and another was half defoliated. The third, much the strongest, was not attacked significantly. These beetles sense which trees are the weakest and go after them like lions hunting prey in Africa?

Anyway, as for the baldcypress this year--I have given them a light spray and placed beetle traps upwind, and so far they have lost no foliage that I can see.

One strange thing is the beetles love to attack two DED resistant elm trees I got from the Elm Research Institute (I think that is the right name), but they don't attack volunteer elm seedlings and saplings that will die soon anyway. These beetles are real bastards and will do anything to frustrate our best intentions.

--Spruce

I had no idea they went after dawn redwoods as a particular favorite. I thought it strange that they had managed to get inside the milk jugs that are housing my winter sown DR seedlings and chewed them up. I have definitely noticed a favoritism toward cherries, rose of sharon, roses, bee balm petals, and shasta daisy and cone flower petals. I typically hand pick them, and I have plenty of scunks in the area digging up the grubs in the spring time. The ants do a pretty good job of taking care of the grubs too.

I had same problem last year with a weeping bald cypress ... was very upsetting

This year I uased a Bayer product that you mix and pour around the base of the plant (amount applied depends on diameter of trunk) ... I used it on multiple plants including my weeping bald cypress, japanese maples & crepe myrtles ... I was AMAZED how it kept all bugs at bay including the Japanese Beetles ... I will use it again. I did NOT spray it on a plant that the beetles love ... I let them have at that one

I also have had very good results with the same Bayer product esp. with the dawn redwoods, larix and bald cypress. Previous years I had near complete defoliation due to JB.

We planted a purple norway maple and a purple crab apple tree this past spring. They and my hollyhocks and roses are just a delicacy for the darn JB. I placed pheromone traps out in the front corner of my yard near the street and had to empty it nearly every day! I still had my trees full of beetles. I am going to try beneficial nemetodes next year.

I read a post where a lady put the trap over a bucket of soapy water and a pvc pipe about 1/2 inch in diameter from the bottom of the trap bag into the bucket. The beetles drop in and drown. I'm also going to try that next year to save the constant filling and replacing of the trap bags. I live in NW AR in the Ozarks oak forest, and am surrounded by other yards and woods so I'll never get ahead of the invasion.