Crape myrtle scale finds its way to Brazos Valley

Crape myrtles have adapted well to the climate of the south and southeastern United States. They are a significant component of low-maintenance landscape. One of the toughest and showiest plants for Texas landscapes, their colorful flowers, long bloom season, attractive bark and beautiful shape make them among our most valued landscape ornamentals.

For many years, a fungal disease -- powdery mildew -- was the major pest of crape myrtles, but hybridizers were successful in breeding resistance into newer varieties. However, a new pest is causing some concern. Crape myrtle scale, which first appeared in the Dallas area in 2004, seems to be spreading and has found its way to Brazos County.

No cause for alarm though, as experts are hard at work and already have some suggestions for managing this unwelcome intruder. In a May 2, 2014, news release by Ag Communications, Steve Byrns shared the following information on this pest from two Texas A&M AgriLife Extension Service experts.

Dr. Mike Merchant, AgriLife Extension urban entomologist at Dallas, said the new scale pest turns the bark of crape myrtle trees an ugly black color .

"We are still figuring out the identity of this insect, but we believe it is Eriococcus lagerstromemia, a scale previously known only from Asia," said Merchant. "We've been referring to it as the crape myrtle bark scale."

Dr. Mengmeng Gu, AgriLife Extension horticulture specialist at College Station, had the chance to see the scale up close in its native China during a trip she made there last year.

"It's not pretty," she said. "Crape myrtles we saw in Chinese gardens show the same symptoms as trees here in Texas." Gu's horticultural contacts in other states revealed that the pest is not restricted to the Dallas area as was previously thought.

"As of today, scale infestations have been found on crape myrtles in North Texas, College Station, Oklahoma, Arkansas, Louisiana and in the Memphis, Tenn. area," she said.

Official confirmation of the scientific name must await verification by molecular biologists and taxonomists, Merchant said. In the meantime, he said the pest continues to spread.

Merchant first discovered the scale on a commercial property at Richardson in 2004. "We believe someone brought a cutting of crape myrtle that was infested with this scale into the country in luggage," he said. "It's a perfect example of why it's a bad idea to bring home undeclared illegal plant material from other countries."

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Crape myrtle scale finds its way to Brazos Valley