by CHRIS WINSLOW
The rains of last winter, May and July have been such a wonderful blessing for all our landscapes, bringing lots of fresh growth to the trees and shrubs that had been stressed by last year’s record drought and heat. However it’s not all good news.
Along with this incredible flush of growth comes an explosion of the aphid population, bringing with it the dreaded ‘sooty mold’ (Ascomycete fungi) which can turn a beautiful tree into a black, gooey mess. Trees most affected? Crape myrtles and pecans.
This sooty mold forms on the leaves because of sap-feeding insects. Mostly this means aphids, but it could also be scale insects and whitefly.
As the aphids feed on the sap within the leaves, they exude a sticky, sweet substance called honeydew. The mold then adheres to the leaves, blocking sunlight and causing the leaves to turn yellow.
While this is all very unpleasant to the eye, mold hardly ever actually kills crape myrtles, although it can stunt new growth.
The biggest problem is cosmetic. The mold can spread to grass, driveways, lower plants, cars, and decks. It just makes a nightmare of a mess.
What’s the solution? You need to get an effective organic product that you can spray on the leaves to kill off the evil sap-sucking aphids.
My favorite is Organicide. It contains sesame oil, edible fish oil and lecithin, and this combination suffocates aphids and acts as a fungicide to eliminate the mold.
Two other good products are Neem and All Seasons oil. Take care to use these in the cooler parts of the day. Temperatures above 85 degrees can cause these products to burn the leaves.
For taller trees, a hose-end sprayer works well. (Organicide and All Seasons oil can be purchased with a sprayer attached.)
So fellow gardeners, if you stop the aphids, the sooty mold will magically disappear.
As Roseanna Danna once said, “It just goes to show! It’s always something!”
Happy gardening everyone! If you have a question for Chris, send it via email to [email protected]. Or mail a postcard to 11726 Manchaca Road, Austin, TX 78748.
