I didn't think we had it in our area (yet). Maybe it's something else...if so..any ideas?
The new, young, tender growth is getting hit the hardest. This pic is of some older leaves on a Page mandarin.
classic CLM... sorry
Crap. Now what? This isn't supposed to be in Nor Cal, is it? Where do I report this? Should I do an all-out assault on the trees?
Report the infestation to your County's Agricultural Commission.
Serge, CLM has been in Northern Ca for at least two years now, maybe three. So don't bother reporting it, they know by now.
Spinosad is the best choice once it's started, Imicloped in Bayer Fruit and Veg, is good for protecting the trees before the out break.
Neem oil has been suggested but I don't see it doing any good except perhaps to suffocate them as they exit the leaf protection and make their cocoon on the outside edge of the leaf.
Fyi, if you look carefully you may see the edge of the leaf folded over in one spot. Unfold it and you may see the tiny cocoon. If it's plump it's still in there, if it's not and there's a tiny hole at one end, it's gone. (if it's still there I squish it! Not much good for the long run, but satisfying! LOL)
There seems to be about two "seasons" of CLM, one in early spring with the first new leaves flushing and one in late summer/ early fall with the second flush of new leaves. CLM only attacks the new leaves. On large older trees it's just a minor annoyance, but on young trees, new growth is such a large % of the tree that CLM can stunt the growth.
Last winter, about Dec. I used the Bayer Fruit and Veg. and had no CLM this spring. However, I missed timing it for the fall season and now have some damage. Spinosad (in Bonide "Captain Jack's Dead Bug Brew" and other like products) is the choice now that I missed the Bayer timing. There are several generations in the month or so "CLM season" so you can still catch the next couple generations with the spinosad.
Btw, spinosad is registered for organic gardening. Once it's dry it has no affect on beneficials crawling on it, it only works when the insect chews the leaf. Spray in the early evening when beneficials have gone home, and it will be dry by morning. Spinosad is not poisonous sprayed on them but it could drown them.
Bayer Fruit and Veg is not organic, I find it has better control, but has to be used ahead of infection to work the best. It also has low impact on beneficial insects.
Don't bother to cut off affected leaves, it only encourages new growth to be infected and even if they're curled, the leaf is still able to make food, so just leave them, even though they're ugly.
Good luck, don't panic. CLM is annoying but not lethal, and it doesn't affect the fruit. If you've read this far, sorry for the novel length post! lol.
This post was edited by BarbJP on Fri, Aug 22, 14 at 12:51
Barb, THANK YOU for the long post! I read every word with appreciation. I am going to Spinosad the trees for now and then do a Bayer soil drench in December. I have a lot of young trees that really need the new leaves to thrive. I may have lost 1/2 year but will keep after it. These guys came out of nowhere this fall!
Serge, I think you're confusing CLM with ACP. No need to report this to your ag agent :-) This is an annoying but benign pest. Barb gave you some good advice. Barb, you can combine Spinosad with a hort oil (Neem, Volck, etc.) to help it "stick" to the leaf and last a bit better and longer. Serge, just remember not to use a hort oil if temps exceed 85 degrees, or you can burn the leaves. If you opt to use Imidacloprid, apply two weeks prior to when you expect to see CLM in your area. For us down here in S. California, CLM usually appears around mid-July, so I will apply Imidacloprid around mid to late June, and if we are seeing particularly heavy pressure, again in December. You haven't "lost" anything, just makes the leaves look a little ugly, but your trees will do just fine. Many commercial groves do not treat for CLM, but time their fertilizing to have flush appear early enough that it will be mature and hardened off enough to cause less damage when CLM hits. Treating twice a year with Imidacloprid will also cover you for the ACP, so, although I prefer to use organic methods whenever possible, this is one exception, since the ACP is popping up here and there in California, and making its way north.