Mites Cause Leaf Discoloration and Leaf Drop
Mites are one of our most serious hot weather pests. They multiply rapidly and can cause a lot of damage before we notice it. Mites are tiny pests which feed on the bottom of leaves. They are so tiny that it requires a hand lens to see them.
Their feeding causes leaves to become multi-colored, eventually turning brown and then falling off. They attack conifers as well as broad leaf plants. Check the bottom of multi-colored leaves.
Several pesticides are available which will kill mites. Washing plants with a strong spray of water is somewhat effective in removing them. They cannot find their way back onto plants from the ground. Add insecticidal soap or dish detergent for additional effectiveness. A simple hose nozzle can be used as a sprayer. Use a Siphonex or Hozon attachment to inject soap into the water from a bucket.