Predation by flat bark beetles (Coleoptera: Silvanidae and Laemophloeidae) on coffee berry borer (Coleoptera: Curculionidae) in Hawaii coffee

Abstract

Coffee berry borer (CBB), Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae) is a serious pest of coffee worldwide and a new invasive pest in Hawaii. Adult flat bark beetles, mainly Leptophloeus sp. (75%) and Cathartus quadricollis (21%) (Coleoptera: Laemophloeidae and Silvanidae, respectively), were found inside CBB-infested coffee beans on the tree and molecular marker studies confirmed feeding on CBB. Research was conducted to better understand the ecology of these predators and explore ways to increase their role in suppressing CBB populations in coffee. Laboratory feeding assays demonstrated the capacity for adult and larval flat bark beetles to feed on all CBB life stages. The predators are widely distributed in the coffee growing areas on the island of Hawaii, but feed mainly in dried coffee on the tree rather than in ripening berries where initial crop damage occurs. Berlese funnel extraction of flat bark beetles from dried beans on the tree indicated that predator numbers can be relatively high (up to 23 adult predators per 150 bean sample). C. quadricollis was not susceptible to infection by the fungal biopesticide Beauveria bassiana which is used for field control of CBB in coffee. Leptophloeus sp. and C. quadricollis can be raised easily on a diet of cracked corn and cornmeal. Augmentative releases of generalist flat bark beetle predators like Leptophloeus sp. and C. quadricollis may be a useful component of integrated pest management programs against coffee berry borer and other scolytine pests.