Control tactics for the black twig borer, Xylosandrus compactus (Coleoptera: Curculionidae: Scolytinae), a pest of coffee in Hawaii

The black twig borer (BTB), Xylosandrus compactus (Coleoptera: Curculionidae), is among the most serious pests of coffee and many endemic Hawaiian plants. There is currently no acceptable and effective means of managing it. BTB is a significant concern in the Kona area, and potentially in other Hawaii coffee-growing areas as well. This study combines several complementary approaches focused on understanding the ecology and behavior of BTB as they relate to the development of practical, economical management procedures for.

This study was conducted in coffee farms and a koa field in Kona and Oahu, Hawaii. We studied a) the seasonal fluctuation of BTB, b) the relative effectiveness of different attractants and repellents, and c) cultural and chemical practices (pruning and two formulations of imidacloprid, respectively). Infested coffee branches were collected from each farm to determine the presence of natural enemies. Ethyl alcohol vials were as effective as ethyl alcohol pouches, and were more effective than eugenol and α-pinene. BTB populations showed an aggregated distribution, were present all year round, and were found inside of coffee berries and coffee branches. Verbenone and limonene both significantly reduced trap catch of BTB. The predator beetle, Cryptamorpha desjardinsi, was found feeding on BTB inside the galleries. Provado® and Admire®, two imidacloprid formulations, significantly reduced BTB infestation. Pruning and removal of branches also reduce BTB infestation, but are time consuming. Quantification of BTB population dynamics and the development of effective monitoring procedures enhanced BTB integrated pest management.