by Karen Miller, Master Gardener Entomology Specialist
There are bad bugs, and then, there are bad, bad bugs. Spider mites are bad, bad, bugs and are classed as a type of arachnid. Spider mites are less than 0.04” in size and are difficult to see with the naked eyeThey range in color from red and brown to yellow and green.
Spider mites love hot, dry weather. Temperatures around 80* are considered optimal for the two-spotted spider mite, most common in our area, to hatch in as little as three days.
Spider mites are considered a serious pest inside on houseplants and on many plants around the yard. They congregate on the underside of the leaf where they feed off of the plant fluids while stealing the plants chlorophyll in the process. Visible signs of spider mite damage include webbing and white or yellow speckles on plant leaves. A severe infestation can cause leaves to become discolored, giving a gray or bronze look to the plant. Leaves and needles can become scorched and drop prematurely. Spider mites frequently kill plants or cause serious stress to them.
So how do we get rid of them? One reason the spider mite has become such a problem in our yards and gardens is the use of insecticides that destroy their natural enemies. Because of their rapid reproduction rate, the spider mite can adapt quickly to resist certain pesticides especially when used over a long period of time. Miticides or acaricides are a good chemical control of spider mites. These are pesticides developed specifically for spider mite control. Be aware though, miticides do not affect the eggs, so repeat the application again in approximately 10 to 14 days for complete control.
Stressed or weak plants are the likely target of the spider mite. Plants stressed by drought can produce changes in their chemistry that make them more appealing to spider mites. Adequate watering of plants during dry condition can limit drought stress. Just a periodic hosing of your plants with a forceful jet of water can physically remove and kill many mites.