Predaceous flat bark beetles munch on coffee berry borer in Hawaii coffee

The coffee berry borer (CBB), Hypothenemus hampei, 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: Silvanidae and Laemophloeidae, respectively), were found feeding on CBB in coffee trees.  Research was conducted to better understand the ecology of these predators and explore ways to increase their role in suppressing CBB populations in coffee.  Feeding assays demonstrated the capacity for adult and larval flat bark beetles to feed on all CBB life stages in the laboratory.  Molecular markers were developed to detect CBB in predator guts, and analysis of collections from coffee in the field showed that the majority of flat bark beetles were feeding on CBB. The predators are widely distributed in the coffee growing area of the Big Island, but feed mainly in dried coffee on the tree rather than in ripening cherry where crop damage occurs. Berlese funnel extraction of flat bark beetles from dried beans on the tree, indicated that predator numbers can be extraordinarily high (e.g. 25 adult predators per 150 bean sample).  Reproduction occurs in macadamia nuts but not in coffee. C. quadricollis can be raised on a cracked corn-cornmeal diet, and a raise and release program was started by providing farmers with a starter kit. Over 200 predator starter kits were handed out to coffee farmers during four workshops on the Big Island.  The predators do not appear to be susceptible to Beauveria bassiana which is used for field control of CBB in coffee.