Dear All, After reading your contributions about Imidacloprid I feel like adding another point of view. It is a product by Bayer and sold under the brand name of Provado here in Germany. It is relatively new and indeed is very effective. It has no smell (many pesticides are mixed with an agent that makes them smell "poisonous" in order to increase the safety of the product) is not visible after spraying and has not done any leaf damage even to hairy Gesneriad leaves. It is extremely long lasting after spraying, one spraying is said to be effective for a "considerable time" but the instruction on the box does not say for how long exactly. It says strictly one treatment only but scale insects may not be fully controlled (yes, I agreee) I spoke quite enthusiastically to a professional gardener about this product as I thought I had found the perfect cure for all the pests. But he warned me saying that by eyperience such potent products will sooner or later develop resistences in many insects and for this reason it is better to use other, less potent products in between. Besides this it is dangerous do bees and must not be sprayed onto flowering plants (it does not say for how long before flowering) The touble with bee-toxic products is that it may kill the bee but even worse if the bee is not killed it will carry the poison into the honey.... All the best! Uli