Aerosol delivery of pheromones in IFP: A mature technology for plant protection

Abstract: The discovery of pheromones, specifically sex pheromones of Lepidoptera, and subsequent identification of pheromone chemical structure(s) led to their synthesis and eventually to the development of commercial products, first as components of monitoring systems and eventually as pheromone dispensers for control of agricultural pests. In pome fruit pheromone technology has primarily targeted the codling moth (CM), Cydia pomonella (L.). Initial pheromone dispensing technologies were comprised of plastic packets, tubes or solid matrices where pheromone evaporated from the dispenser surface. These dispensers were typically applied by hand at densities of 500 to 1,000 units per hectare. For many agricultural pests these hand-applied pheromone dispenser systems worked very well, though labor required to apply dispensers has been often raised as a concern for growers. The development of aerosol pheromone delivery technology applied at a density of 2-2.5 units per ha is an alternative to passive pheromone release technologies. This report summarizes results of five years of research trials comparing aerosol pheromone delivery technology with a standard hand-applied pheromone product, Isomate® CM Flex, conducted in Washington State with treatments challenged by the release of sterile CM. There was very little difference between the Isomate® CM Flex treatment and aerosol treatments, Checkmate® Puffer® CM-O or Isomate® CM MIST, when the aerosol treatments were releasing 100% or 50% of registered rates. However, when pheromone release rates in aerosol treatments were 25% or less of the full rate, suppression of sterile CM capture was less than in the Isomate® CM Flex treatment. For the Isomate® CM MIST technology reducing the hours of pheromone release from 12 h to 7 h did not impact suppression of CM captures. Average fruit injury by Checkmate® Puffer® CM-O and Isomate® CM MIST treatments was not different. There was a decline in fruit injury associated with aerosol treatments releasing lower levels of CM pheromone. The pros and cons of the aerosol technology of delivering pheromones are discussed.