I have those on all my trees. They don't seem to cause any problem. You might try soapy water and hit them direct and see what happens. I do nothing and have no problems.

Steve

Those are Giant White Flies, a terrible pest we have here in S. California, serge. They have particular plant favorites - hibiscus, canna, xylosma. So much so, many S. California gardeners have refused to plant those 3 above plants, for fear of harboring Giant White Fly in their yards. They are extremely difficult to eradicate. Here is some information on them, and how to manage them in your yard. I would also talk with your local Master Gardeners and better garden center on tips on management. Sorry, Steve, this is not a harmless pest for us in S. California, and what you have may not be what we have here in S. California. Better to try to avoid insecticides, as they can also kill beneficials, such as lace wing, lady beetles, syrphid flies, and parasitic wasps. Try removing infested leaves, look under leaves for the distinctive concentric white whorls of eggs. Wash those off with water and insecticidal soap (in the evening, to help protect certain beneficials). Remove leaf droppings, and apply worm castings to help affected plants recover faster. There is a product called Naturalus T & O that is organic, and supposed to be very effective, but it is rather expensive. Some folks have even resorted to vacuuming up large amounts of adults, to reduce adult populations. You can also try Neem oil to smother the nymphs, although I am not sure of the efficacy. It certainly won't hurt, as long as you apply in the evening, and temps are below 85 degrees. This is the season to see adults massing to lay eggs, so you're catching the infestation at a good time. I would start searching your yard to see if you have infestations in the more preferred plants, and start your clean up, there.

Patty S.

Here is a link that might be useful: UC IPM: Giant White Fly

White flies - I battle these (or a cousin of these) too. I hang yellow sticky traps and spray occasionally with soapy water.

They seem to prefer oregano, thyme and mint. I have not seen them attack the citrus.

- George

I don't think I have giant ones, but my hibiscus have bounced back nicely since I've started spraying the heck out of them with the garden hose every few days.

Come to think of it, they probably just liked being watered for a change.

Mint! Maybe that's the culprit. Out it goes. Thanks for all the advice. Perhaps a neighbor planted something. I will look around. Meanwhile, it's water and neem and I will check out the Naturalus T & O.

I don't think i was clear. Having the mint/thyme/oregano keeps them away from the citrus. So my citrus is safe(r) by having the mint.

BTW: They also go after the fresh coastal oak leaves...

Thanks, George - I almost pulled out that mint!!!

Fori, they almost certainly are Giant White Fly, if you live in S. California. The name doesn't mean they're "giant". They are small - tiny, but larger than other species of white flies. Serge, before you go ripping out all your mint (or any other plant), look for the very distinctive white concentric circles/whorls under the leaves of the plants I've mentioned, or ones on the link I provided you. Just because you have mint in your yard, doesn't mean it's the mint that is attracting Giant White Fly. I have a yard FULL of hibiscus. Even though most folks here in S. California will refuse to grow hibiscus (or Xylosma), due to the propensity for Giant White Fly to infest these two plants, I never once have had Giant White Fly on a single one of my hibiscus. Instead, they went after my hydrangeas one year, then my cannas the next year. And, mint/thyme/oregano doesn't keep them away, sadly. They are terrible, and they will massively infect certain plants, and rotate around your yard from year to year. You need to look to see where they're congregating and laying their eggs, and treat those areas of your yard and affected plants. I am not willing to part with my hibiscus, some of which are rare and spectacular cultivars. So, I treat when I find them. The drier it is, the worse they can be. Just like spider mites.

Patty S.

This post was edited by hoosierquilt on Thu, Aug 21, 14 at 0:08