Distribution, Host Plants, and Damage of the Black Twig Borer, Xylosandrus compactus (Eichhoff), in South Carolina

The black twig borer, Xylosandrus compactus (Eichhoff) (Coleoptera: Curculionidae: Scolytinae), is an exotic ambrosia beetle that can be a severe pest of ornamental trees and shrubs in the landscape of South Carolina. This paper reports on the beetle's distribution and host plants in South Carolina. Descriptive data on the severity of attacks in different locations and at specific heights of southern magnolia (Magnolia grandiflora L.) trees were also gathered. Xylosandrus compactus was trapped or observed in 18 counties in South Carolina, from the Atlantic Coast to the upper Piedmont regions. The recorded ornamental host plants of X. compactus in South Carolina include Buxus sempervirens L. (boxwood), Cercis canadensis L. (eastern redbud), Cornus florida L. (flowering dogwood), Ficus carica L. (common fig), Gardenia jasminoides J. Ellis (gardenia), Hydrangea macrophylla (Thunb.) Ser. (hydrangea), Magnolia grandiflora, Morella ( = Myrica) cerifera (L.) Small (wax myrtle), and Pinus sp. (pine). On average, 47% of southern magnolia trees in seven neighborhoods of North Myrtle Beach, SC suffered attacks by X. compactus. Southern magnolia terminals at a height of 0–1 m (from soil surface) suffered the highest percentage of attacks (11.1%), followed by those at 1–2 m (7.2%). The percentage of terminals attacked was reduced to less than 4% at 3–6 m. The tendency for X. compactus to infest terminals at heights less than two meters suggests that preventive insecticide applications should target the lower branches to reduce damage.