Q: My neighbor has a beautiful crepe myrtle that hangs over my driveway. Sap drips all over my car that is sticky and hard to clean off the window. Someone said it might be a bug that is on the tree causing the sappy like stuff to come down? Do you know what this could be and how I can stop the sap? My neighbor is willing to work with me on this. A.R., Dallas.
A: The dripping is the waste or "honeydew" of small insects called aphids or plant lice. They can be temporarily eliminated with strong sprays of anything, including water. Compost tea with orange oil or other plant oil products added to the water works better of course. The strong spray rips the pests off leaving their mouth parts still stuck in the plant tissue killing most of them. But, they will come right back unless the stress in the trees that brought them on in the first place is removed. Stress in the plant can be caused by too much or too little water, too much or the wrong kind of fertilizer, soil compaction, and soil contamination caused by herbicides and other toxic chemicals. One of the most common causes of stress in trees is deep planting. Make sure the tree is not too deep. The root flare should be exposed and visible above the ground. You can remove the soil yourself if the work is done very carefully, it’s best to hire an arborist to remove the soil with the device called the Air Spade.