Does anyone know whet these critters are?. The have appeared suddenly on several of my greenhouse sempervivums and some sedums. So far the plants seem OK. The bugs are REALLY small and white - the plant shown is only a little over an inch in diameter for reference.
Sorry about picture quality but it's as close as I can get with my point-and-shoot.
Thanks! - Kevin
These are small sap-feeding insects in the suborder Sternorrhyncha of the order Hemiptera; either aphids (family Aphididae) or whiteflies (family Aleyrodidae). The image is not clear enough to be certain, but to me, the white objects look more like the shed 'skins' (exuviae) of aphids (see http://tinyurl.com/ydgmbwr) than whiteflies (see http://tinyurl.com/ybef2ql). In either case, you can try applying an insecticidal soap (such as Safer Insecticidal Soap) or a light horticultural oil (such as Ortho Horticultural Spray Oil) to control them.
Suunto - from the looks of the photos you linked to I agree I am indeed seeing the shed skins of aphids.
The strongest pesticide I use is a rare spot pyrethrin based spray treatment so I have a pretty good ecosystem in the greenhouse over the winter from small lizards to ladybugs. I haven't actually seen any aphids yet (just the shed skins) so maybe, hopefully something ate them after they hatched. I'll keep an eye out.
Thanks for the info - much appreciated. Now I know what I'm dealing with! - Kevin
You can use rubbing alcohol to kill them. Be sure to not only cover all sides of the leaf and stem, but thoroughly drench the soil to kill any that have made their way onto the roots too. I think the mix is 50-50% with water.
