A Novel Isoxazoline for Protection of Coffee Beans: Lethal and Sublethal Effects of Isocycloseram on the Coffee Berry Borer, Hypothenemus hampei (Ferrari)

Abstract Isocycloseram is a novel isoxazoline with insecticidal activity as a modulator of the GABA-gated chloride channel. We assessed relevant biological effects of isocycloseram on the coffee berry borer, a destructive pest causing over US$500 million in annual losses to coffee production globally. In berry-immersion bioassays, the manufacturer-recommended label concentration prevented damage to coffee beans and caused more than 90% mortality within 30 days of exposure. The median lethal concentration (LC50) was 34.05 mg/L. Isocycloseram concentrations three- and nine-fold lower than the recommended rate also reduced pest offspring production and decreased gallery formation within coffee beans, as revealed by X-ray radiography. Notably, protection of the coffee bean was achieved at concentrations substantially below the recommended field rate. Therefore, isocycloseram affects the coffee berry borer through a combination of lethal and sublethal responses and can provide effective protection of coffee beans while contributing to integrated pest management programs for this economically important pest.