2013 Annual Report
Field trials were concluded during 2012 and new field trials were established in 2013 to test hypotheses related to the effect of intentional coverage gaps and pheromone formulation on efficacy and longevity of pheromone-mediated mating disruption of citrus leafminer following applications of SPLAT CLM™ to citrus groves at locations in Florida. SPLAT CLM failed to provide trap catch disruption previously observed with this product and this was traced to a probable interaction between the active pheromone compound and a wax component. Working closely with industry partners (ISCA Technologies, Riverside, CA), ARS quickly deployed solid rubber dispensers in place of the SPLAT-based product with excellent results. In commercial citrus groves, longevity of trap catch disruption exceeded 30 weeks. This discovery of prolonged efficacy with solid rubber dispensers propelled the development of a new product designed to be placed by hand in citrus trees. Labor costs are offset by product longevity; a single hand application may provide yearlong trap catch disruption.
Additional trials were established during 2012 and 2013 to study male and female flight behavior to estimate the ability of gravid females to migrate into grove areas treated with pheromone. Females were found to oviposit on sentinel citrus trees located as far as 1.2 km away from citrus known to be infested by citrus leafminer. This suggests that the ability of pheromone products to reduce infestation and resultant mining damage is dependent on the size of the area treated. Further trials are planned to test this hypothesis by treating areas approaching 1,000 acres each.