Question
help!! My crate myrtles are being invaded by these ladybug size critters. They are attached to the leaves like a tick does on humans. My plants are all turning blace even the limbs and leaves. What are these things called and will I be able to save the plants. I also have white bugs on some of the others as well. I live in Austin Texas and we had a solid month of rain as well. HELP ME if you can.

Answer
The insects that are attached to the plant are called scale insects and the white "bugs" sound like aphids. Both of these insects suck the plant juices from the tree and excrete a substance called honeydew. Honeydew has a high content of sugar and is sticky to the touch. A black sooty mold will grow on the honeydew making the plant turn a black color. Control the scales and aphids and the sooty mold will be washed away with rainfall.
The best way to control the scale and aphids is by either spraying the foliage and trunk with a contact insecticide or using a systemic insecticide applied to the soil. Systemic insecticides are taken up by the roots and transported to all parts of the plant and when the sucking insects fed the insecticide kills them. Contact insecticides sprayed on the foliage will kill the insect on contact.

Apply insecticide sprays (such as malathion, bifenthrin, cyfluthrin, permethrin or similar products) to base, trunk and limbs--wherever scales are found. A follow-up spray 10-14 days later may be necessary to kill newly emerged nymphs.

Imidacloprid (Merit?or Bayer Advanced?Garden Tree and Shrub Insect Control), dinotefuran (Spectracide?Systemic Tree and Shrub Insect Control Plus Fertilizer) and acephate (e.g., Orthene? are three systemic insecticides that are generally effective against sap feeding insects. When drenching the soil with systemic insecticides, allow several weeks for control as the products need time to spread throughout the plant.