I have been adding copious amounts of compost to what once California adobe for years. Now, I have rich loam and...huge (3+ inch) grubs. I did some research on the grub issue and have read that they are more common in soil high in organic content. I have milky spore on order to (hopefully) help combat the issue but was wondering if anyone else has run into this issue? If so, any other suggestions outside of pesticides (as we don't use them? These are not the common turf grub (in fact, I have not found any in the limited grassy areas we have) but rather, their population is exploding in the garden and vege beds (and are now settling in the potted plants). I realize that milky spore may not help due to the type of grub but I am desperate to tackle this issue as they are causing horrific damage at this point.

http://www.ipm.ucdavis.edu/PMG...

The first is from UC Davis, but it looks like it refers mostly to the turn grubs.

http://forums.gardenweb.com/fo...

And this is from the California garden forum at GW.

You say you don't think they are turf grubs. Any way of telling if they are beetle larvae? Are they confined to the compost pile -- and maybe they are just doing their job?

I would tend to say a handful of diatomaceous earth to the compost pile might do them in, but it would be better to find out why they are there and what they are up to. Figs?

Oh dear - I thought I had responded to this. My apologies.

These grubs are actually throughout the garden. We have a blue and green metallic "june-bug"-like infestation (not the green june bug that is normally seen) annually and I think this is their grub stage. They showed up for the first time 5-7 years ago in the fruit trees. At the time, I spoke to the nursery down the street and they said that the area had been hit by Japanese Beetles but they don't resemble the photos I have seen on the net. Also, these bugs and grubs are a lot larger than that of the Japanese Beetle. I have noticed that as the grub population has grown, so has the annual "june-bug" infestation.

I would check in with your county extension agent (do they have those in California?) or call U. C. Davis to find out more about identification and habits. If the grubs coagulate anywhere in your yard you could douse them with diatomaceous earth (d.e.).
Other wise, I would watch and learn. Are they doing any harm, or are they doing some good, or, are they just minding their own business? There may be some kind of plants that might discourage them, marigolds for example. If they are crop theatening Im sure your local ag college has information.

Or get a couple of chickens. they love them!

Following up what Hazelnut said, which So. Cal. county are you in? The UC overall coop website says they can't advise on specific pest situations, and refer people to the county extension offices:

http://ucanr.org/County_Office...

here are some links to the overall UC Coop Extension program:

UC Cooperative Extension | Agricultural Experiment Station
http://ucanr.edu/


Most of the UC site describes pest management by crop, not by pest. But here are some links within their environmentally sound, Integrated Pest Management area:

http://www.ipm.ucdavis.edu/ind...

UC IPM Online
Home, garden, turf, and landscape pests
http://www.ipm.ucdavis.edu/PMG...

UC IPM Online
Insects, mites, mollusks, nematodes
http://www.ipm.ucdavis.edu/PMG...

UC IPM Online
Beetles & grubs
http://www.ipm.ucdavis.edu/PMG...


UC IPM Online
Pest Management Guidelines: PDF files


Links to pest management sites:
http://www.ipm.ucdavis.edu/GEN...


Maybe email some photos to the Master Gardner organization to identify the exact variety of grub and beetle? How many 3-inch grubs can there BE?

I see that you're already very familiar with the ATP Pest Forum! I see your name there a lot.

So much for suggesting posting photos there for grub identification.

Good advice, Rick.

Your county agent is a good guy to know. And in some cases, they are even women!

If you type in Green fruit Beetle to to your browser, I think you'll find your culprit.

Thanks, ctcarol.

http://www.ehow.com/how_863117...

Is this him?

You Tell me. This is the one you described. I see them around here in late summer/fall bumping into everything and I find dead ones around. I don't know without doing some research if the grubs do any harm. If you check some of those other sites I'm sure you can find out about the grubs.

Oldgardener, so you get these also. Here we call them green June beetles. They lay hundreds of eggs. They are normally satisfied to lay their eggs in the small woodland behind our house unless it's to dry there. They love moist compost rich ground as the larvae feed on the decaying material. So your garden is providing what they need. Grubs grow to 3 inches or more if well fead. Then when your garden begins to dry or they run out of organic matter to eat they go for the roots to survive. Dug up a rather newly planted rose that had perished (this never happens). I had gotten lazy and just improved the hole. I knew better but did it any way. So when digging I counted 30+ giant grubs in there with one big one hanging onto the last piece of root left. Now I keep a spot for the beetles if the weather has dried their habitat. A moist pile of decaying grass and leaves. After adult beetles leave I spread it out so it dries quickly in the summer sun killing the grubs. Amazing site to see. Hundreds of grubs piled on top of each other. Yuk!

I just turned over a compost pile and found maybe a dozen grubs in it. The pile was not up to the normal standard of mine, and was pretty much left alone for the past two months. I am thinking of trying to use the grubs for fishbait.

I bet the birds loved you for exposing the grubs!

I saw a video somewhere about someone with large windrows of some kind of compost. He unleashed his flock of chickens on those windows, and he said they ground up the surface layers for him, turned it a little, and found lots of bugs and such for themselves.