In Situ Measurement of Airborne Pheromone Concentrations and Their Relationship With Dispenser Release Rates for...

For the control of pests by mating disruption (MD), passive pheromone dispensers are now widely used and have proved their efficacy. Although the release rate of dispensers and its change over time are usually well assessed, the airborne pheromone concentrations generated in a treated area are generally unknown. This hinders the development and optimisation of the treatment by MD. The present work reports the results of a field campaign of measurements carried out with the aim of quantifying airborne concentrations of dodecyl acetate released by passive dispensers distributed over a covered crop area. Dodecyl acetate is used as a model pheromone due to its low reactivity in the air allowing the release and dispersion processes to be characterized. The relationship between emissions and ambient air concentrations was investigated using both an empirical approach and an atmospheric dispersion model. Ambient air concentrations in the crop area were predicted by combining a previously developed emission model with temperature and wind speed data. The measured airborne concentrations ranged from 16 to 113 ng m^-3 depending on the location of sampling and the release rate of dispensers at the time of sampling. The treatment-level concentrations persisted all along the sampling period for at least 44 days, while temporal changes in airborne concentration were mainly driven by the release rate of dispensers and its dependence on temperature.