An overview of pests of houseplants, nonchemical control, and pesticides is at: http://extension.umn.edu/distribution/… With a few more photos and a timely revision, the site would be top-notch. Imidacloprid is not included in the above because it is too new. An assessment of it is found here: http://colostate.edu/Depts/CoopExt/… Reported as having lower human toxicity than Dysyston (Disulfoton), it is highly effective with Homoptera (e.g., aphids, soft scales, mealybugs, whiteflies) but useless with spider mites. One formulation is in a potting soil. Tom Stuart, snowbound in New York a good collection of spiders doesn't hurt, either