The summer sun is hot, and the heavy clay soil is cracking two signs that the July heat is here for a while.

Also there are spider mites.

Able to live on most landscape trees and shrubs, spider mites are hard to see but their damage is not hard to find. If you have leaves on trees and shrubs turning off color and beginning to fall, take a close look, they may be infested with spider mites.

Here are some tips and tricks to help you and your plant recover from the deadly attack.

Spider mites are not true insects but are more closely related to spiders and chiggers. They are extremely small and are hard to see with the unaided eye. Their body color varies from yellow to pale green and they usually have a dark spot on each side of the dorsal midline. Adult females overwinter and may turn an orange color in late fall.

As the weather warms in the spring, the female will begin laying eggs. The whole process from egg to adult normally takes from 10 to 14 days during the summer, with individual females living an average of two months. With from 10 to 12 generations per year, their numbers can grow to damaging levels quickly.

Mites cause damage by feeding on the lower leaf surface. They use piercing mouthparts to stab and suck the juice of individual cells. As the cells collapse, they turn chlorotic, giving the leaf a golden yellow, spotted appearance. Eventually, the leaf dies and falls off.

If leaves are falling from your landscape plants and mites are suspected, hold a sheet of white paper beneath a branch and tap the branch. Mites will be dislodged and can be seen as tiny specks moving about on the paper.

Once identified, there are a few control strategies to choose from. Mites can be knocked off the plant with a steady hard stream of water. Do this daily for several days then check for survivors. Although slow and not always effective, it is safe and easy to do.

A second, more successful method of control is with insecticidal soaps. Available at most garden centers and retail outlets, soap is safe for the environment.

The final option is traditional insecticides. For the best control use Kelthane or Orthene. Here again, because their populations rise so quickly, frequent spraying is needed. Make sure, however, you read and follow all label directions.

Bruce Chladny is horticulture agent at K-State Research and Extension-Douglas County. For more information, call him at 843-7058 from 8 a.m. to 5 p.m. weekdays.