Q: Every year at this time I have a problem with spider mites attacking my orange jubilee and torch bougainvillea. I’ve tried everything but nothing seems to stop them (except hosing them down). Any suggestions?
A: The hose is a good solution, especially in drier times of the year. Since mite infestations are directly proportionate to increasingly warmer and drier temperatures, it would be best to keep an eye on these plants early in the spring and knock back the populations before they get out of hand. Also be sure to maintain the overall health of the plant so it can better handle the pest pressure. Irrigate in dry weather, of course, and avoid over fertilization because the extra nitrogen makes them more attractive. In addition to the hose, infested areas can also be sprayed with insecticidal soap and horticultural oil products. During the winter or early spring control can be obtained with a dormant oil application in many cases. During the summer or growing season use a miticide or insecticidal soap. Check local stores to see what’s for sale. Most insecticides are not effective on mites and some, especially broad-spectrum products such as carbaryl (Sevin) result in increased mite damage by killing their natural enemies. The important thing is to check the label to make sure a product is not hazardous to beneficial predators. And of course any time you use a pesticide it is important to read the label for your own safety and the safety of nontarget organisms around the area.
Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to