Trees and shrubs that may be in your yard are threatened with two fatal diseases that could decimate Crape Myrtle and members of the Laurel family, including Sassafras and Spicebush. Please watch these species carefully for signs of infestation. 

 

Crape Myrtle Bark Scale feeds on the phloem of trunks and appears first as a fuzzy, white infestation. The scale exudes honeydew from its feast, leaving a black sooty mold. Infested trees will leaf out later and usually have fewer and smaller flowers than usual. Treatment consists of a soil drench in spring or chemical spraying when the tree is flowering. The spray will also kill pollinators, so flower removal and pruning are recommended before the chemical is applied. Crape Myrtles planted in full sun are more resistant to the scale than those in shaded areas. If the infestation is extensive, cut the tree down and bag it for removal with trash, not with yard waste. Sprouts will quickly emerge around the cut stump; choose three that are evenly spaced and cover the stump with mulch. A new tree should arise with proper care. Other plants susceptible to the scale, if Crape Myrtles are planted nearby, are pomegranate, persimmon, edible fig, boxwood, American beautyberry, cleyera, privet, and raspberries. Closely examine these plants for infestations and treat or dispose of them.

 

Laurel Wilt can quickly kill Sassafras trees and Spicebush, which are excellent native plants. Redbay and other members of the laurel family native to North America can succumb to the disease spread mainly by the redbay ambrosia beetle, according to Kirsten Conrad, the Virginia Cooperative Extension agriculture natural resources agent for Arlington and Alexandria. Identification of the disease requires laboratory analysis of sapwood under bark, which will exhibit dark streaks parallel to the wood grain. The disease was first identified in June in Scott County, Virginia, although it has been present in several southern states for a few years. Experts believe it is spread by moving wood from place to place. If you suspect it, contact Conrad at 703-228-6423 or kirsten.conrad@vt.edu

 

For more on Crape Myrtle Bark Scale:

https://hgic.clemson.edu/factsheet/crapemyrtle-bark-scale/

https://extension.umd.edu/resource/crapemyrtle-bark-scale

 

Additional information about Laurel Wilt:

https://extension.tennessee.edu/publications/Documents/W1007.pdf

https://news.ca.uky.edu/article/laurel-wilt-disease-expands-encroachment-state-trees 

https://epi.ufl.edu/pathogens/plant-pathogens/laurel-wilt/

 

Author: Jo Allen
Published on: Sep 24, 2021, 10:33 PM