12/18/2014 08:32 EST | Updated 02/17/2015 05:59 EST


Now that winter is here, scale insects have started showing up on my potted citrus tree and some orchids. How many other plant pests lurk, ready for a population explosion when conditions become ripe, typically in late winter?

Dowsing plants — especially indoor houseplants — with pesticides is bothersome and hazardous. Repeat applications usually are needed to catch each wave of the emerging pest population at its most susceptible stage. And it's difficult to spray a plant thoroughly while keeping the mist off curtains, windows and furniture. A number of sprays can stain or even dissolve certain finishes or plastics.