Powdery mildew attacks crepe myrtles and other plants especially during humid weather. The control is to apply whole ground cornmeal to the root zone at 2 lbs. per 100 sq ft and spray the foliage with Garrett Juice plus either potassium bicarbonate or cornmeal juice.
Cornmeal juice is made by soaking a pound of cornmeal in 5 gallons of water. Put the cornmeal in a nylon bag made from old panty hose or whatever to keep the larger particles from getting in the water. This cornmeal juice can be used alone or mixed with compost tea or Garrett Juice. Bio Wash works even better.
QUESTION: I discovered white bugs on the branches of our crape myrtle. One branch is covered in them and has turned black. When I attempt to scrape the bugs off, it leaves a red streak. The bugs look like oval discs attached to the branches and trunk. What is this? D.R., Dallas
ANSWER: This is a scale insect that has been attacking crape myrtles. Use my Sick Tree Treatment and spray with a mixture of Garrett Juice and orange oil or horticultural oil (follow label directions).
QUESTION: We have five large crape myrtles that are about 10 years old. Four have purple flowers, and the largest has white flowers. We recently noticed that where the white tree has been trimmed over the years there are small, egglike, white Styrofoam-looking capsules on the bark. When we mash these white capsules, they turn purple. We’ve also noticed small ants on the tree. M.N., Dallas
ANSWER: The ants aren’t a problem. The capsules are scale insects, which can be killed by spraying a solution made with 2 ounces of orange oil and 1 ounce of Bio Wash per gallon of water.