Monday, February 24, 2020

Crepe Myrtle Bark Scale

Horticulture Hotline 02/24/20
By Bill Lamson-Scribner

I was at a friend’s birthday party the other day in Mt Pleasant (yes, people I work with I do do something other than write recommendations on how to correct your soil based on soil test), and several people commented to me how they enjoy reading the Horticulture Hotline in the Moultrie News. I let them know they should thank Vickey Boyd (The Publisher) and Cecilia Brown (The Editor) for putting up with me for so long.

It is amazing the changes in technology in the 30 + years I have been writing this column. I use to drive my article to the editor because I didn’t trust my fax machine. Then I started to fax even though I still didn’t understand how it worked. Now I email the article to Cecilia.

Crepe Myrtle Bark Scale (CMBS) is getting closer and closer to us. I have had friends in Charlotte sending me pictures for years and now CMBS is in Columbia. CMBS is in parts of Georgia, Texas and many other states. It is a scale that produces a lot of honey dew and eventually turns the tree black. Since the Crepe Myrtle is known for its beautiful smooth and sculptured bark, having sooty mold all over it is not desirable. The health of the tree and the blooms are also affected.

Crepe Myrtle Bark Scale looks like mealybugs or cottony cushion scale to me. CMBS has crawler stages like other scale that you can try to target with a contact like horticultural oil mixed with Bifen. Just be careful of overspray onto flowering plants that pollinators might be visiting. Because of the pollinators, the long-term residual and the difficulty of spraying a tree, I like to use a drench. Some good drenches available contain imidacloprid (Dominion, Tree and Shrub Drench) or dinotefuran (Safari, Zylam).

If your Crepe Myrtle is in a bed with many other plants, using Safari as a basal trunk application works best. If you use a drench and a lot of plants roots are sucking up the material, you might not get enough product into the tree you are treating. With a basal bark treatment, you apply the product directly to the tree itself (in the old days we used to paint product onto the trunk). Since Crepe Myrtles have very thin bark, this form of application is perfect for this type of tree, and none of the surrounding plants steal the active ingredient.

Always read, understand and follow product label. The product label is a Federal Law.