Pest : Vine Weevil

[NHATIVE]

Well, if there's one thing I've learned about hobbies, you're always chasing something. Good or bad, trying to improve, etc... Bonsai is no different.

The latest addition to the chase just revealed itself : Vine Weevils. I've got a few maples already suffering from a hard water/pH imbalance induced chlorosis that I've been trying to dial in the last year or so (water quality here is very poor, been using an in-line hose filter and pH down solution with mixed results. I digress) and they continue to also get hammered with pests almost immediately after leaf out. I've had aphids show up before, and I spray with Neem oil which sometimes works and sometimes doesn't. This time as hard as I looked I couldn't find any sign of aphids yet the leaves were still getting attacked, and even one of my collected Ponderosa would have fresh needless and buds chewed off. I finally caught the culprit in the act yesterday. Bad news bears.

I haven't checked the soil on any trees yet, and am very apprehensive about doing so after leaf out, but I have to assume where there's adults there's grubs. Does anybody have a favorite product or method for killing and preventing vine weevils and their resulting damage?

Thanks in advance...

 

[Wires_Guy_wires]

All beetle insecticides (if you count beetles as insects) have been banned here. But I've been succesful using silver fish spray that contains a permethrin.
But that was on an invasive juniper beetle. Not sure if it would work against something else. I do know that the spray I had didn't hurt my plants.

 

[TomB]

The traditional treatment for vine weevil grubs is a soil drench, usually sold especially for that purpose. Don’t know what is sold in your area, but worth a look.
I have also found predatory nematodes effective.
The best solution though is to use a granular substrate, which the grubs tend to avoid.