Eastern Forest Threat Center - Soapberry Borer

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Adult soapberry borers

Adult soapberry borers

Texas Forest Service

Soapberry Borer
Agrilus prionurus

The soapberry borer, a native of Mexico, was first reported in Bastrop County, Texas, in 2003. Since then, it has been detected in several additional counties, including near or within the cities of Austin, College Station, Corpus Christi, Dallas, Fort Worth, Houston, and Waco.

Keywords: Coleoptera, beetle, western soapberry tree, Sapindus drummondii, white spots, flat-headed larvae, exit holes, exposed sapwood, bark chips, girdle

Distribution Map Distribution Source Image

Threat Description

The adult beetle is about ½ in. long, shining black and distinctively marked with four small white spots on the wing covers. Larvae are flat-headed wood borers that may attain an inch or more in length as they mature. After feeding beneath the bark, the larvae bore into the wood to complete development and to pupate. The adult leaves a D-shaped exit hole in the bark as it emerges. Infestations of soapberry borer are similar to those of emerald ash borer, another introduced pest that is killing thousands of ash trees in the Midwest. Infested soapberry trees can be easily recognized by the exposed sapwood that results when birds and squirrels chip off the bark to feed on the larvae. Bark chips accumulate at the base of the tree. A heavily-infested tree will be completely girdled by white larvae feeding beneath the bark. As its populations expand rapidly in Texas, this insect is killing all sizes of soapberry trees larger than 2 inches in diameter. It may eventually threaten western soapberry populations throughout the tree’s range, which extends from northern Mexico to Missouri, and west to Arizona. Western soapberry appears to exhibit little resistance to this introduced pest.