ATTN Owners with Crepe Myrtle trees in your yard

We want to alert you that crepe myrtle scale has started affecting crepe myrtles in Lakeport (around two dozen have been spotted on our crepe myrtles). Although this scale will not kill the trees, it will reduce the flowers, cause unsightly black sooty mold on the trunk and branches, and weaken the trees. The two photos at right show the white scale insects and the black soot on a branch and a closeup of a female crawling on one of our trees, and two photos below show an infected crepe myrtle on the other side of South Lakes Drive and what a tree with prolonged exposure looks like. Note that if your crepe myrtle starts looking like the ones in the photos, you will need RA approval if you want to remove and replace it. Also, this treatment needs to be applied every year (preferably in April so if you want to treat your tree, you should do so immediately). See Fairfax County Master Gardeners for more information. 

The recommended treatment is Ferti-Lome Tree & Shrub Systemic Insect Drench, available at Merrifield or on Amazon (suggestion: measure your tree first so you’ll know how much to order; we used between 16 and 66 ounces on each of Lakeport’s eight crepe myrtles). This is a pesticide, so be sure to follow directions carefully (see below). Because it can kill bees and other pollinators, please wait until sundown to apply since bees are no longer active at that time (if you already have blossoms, bees are likely at your tree). It also can be toxic to pets and people so keep pets away until the ground has dried and attend to all precautions. 

Note: If you see a black beetle with red spots (like the one shown in the photo below that was found on one of our trees), don’t harm it—its larvae, which look like the scale  may be a natural predator of the bark scale.     


  1. Water your tree the night before. 
  2. Measure the circumference (distance around) each trunk at 4 feet above the ground. Write these numbers on a note pad and then add them together. This total is the number of ounces of drench you will need in step 5 below.
  3. If the total is 30 or less, clear a circular area 2 feet from the trunks, removing any sticks, debris, vines, or mulch. Push back the dirt a little to make a small wall around this area, especially on the down-hill side of any slope. If the total from step 2 is greater than 30, clear an area 3-4 feet from the trunks.
  4. If the total from step 1 is less than 50, fill a bucket with 1 gallon of water. If it’s 50 or more, fill the bucket with 2 gallons of water.
  5. Shake the drench container and then use a measuring cup with ounce increments to measure the number of ounces calculated in step 2 above (we have one you can borrow since you don’t want to use the one from your kitchen). 
  6. Pour the drench into the bucket of water and mix.
  7. Slowly pour the drench around the tree trunk within the cleared area you prepared in step 3.
  8. Do not let pets or children in the area until it’s dry and then cover the area with mulch. 
  9. Repeat the following April.

No comments:

Post a Comment