Invasive species troubles crape myrtles

Johnny Morgan, Kilpatrick, Ricky L., Ring, Dennis R.

Crape myrtle bark scale on a tree in the Shreveport area. (Photo by Allen Owings)

News Release Distributed 10/01/13

BATON ROUGE, La. – A new invasive scale insect has been infesting crape myrtles in Shreveport and Dallas and possibly in Houma and Lafayette.

LSU AgCenter area forestry agent Ricky Kilpatrick in Bossier Parish and LSU AgCenter entomologist Dennis Ring say this is the first year that either has heard about the crape myrtle bark scale in Louisiana.

“This insect was first brought to my attention about a year ago by one of the area arborist,” Kilpatrick said. “The problem with these invasive species is we don’t know the extent of damage they produce.”

Another problem that allows the insect to spread uncontrolled is many people may have it on their plants and not know it, he said.

The scale excretes honeydew that coats leaves and limbs, Ring said. “Sooty mold then grows on this honeydew."

“When I first saw it, I thought it was aphid damage because of the sooty mold,” Kilpatrick said. “I’m just afraid that it will continue to spread because people don’t know what it is.”

Ring said this pest has probably been around for a few years and is continuing to spread by human activity.

“We don’t know where it came from to get here,” Ring said. “But we do know that it is known to be in China.”

People are beginning to see the insect in high numbers, and they want to know what it is and what they can do about it.

“The information that I have as far as treatment is what I’ve received from Texas Agri-Life,” Kilpatrick said. “They say a systemic insecticide treatment is best. This is done by soil drenching around the trees from May to July.”

The dormant oil treatments that would be used with other types of scale have not been very effective with this one.

Ring and Kilpatrick advise washing the sooty mold off the trees trunk and limbs, and Kilpatrick said he is hopeful that cold weather may have an effect on the pest.

If you find this scale on your trees, please take a sample to the LSU AgCenter parish office, the experts say.

Johnny Morgan

10/1/2013 11:01:15 PM
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