Development of methods to assess the release of pheromones in the air from dispenser products for improvement of biocontrol solutions
Abstract: Facing the multiple consequences of the use of pesticides, the international objective is to reduce their use in agriculture until their suppression in the future to fight insect pests. M2i develops different types of products (sprays and breads) based on sex pheromones synthesized in laboratory and which are then introduced in crops to create a mating disruption and reduce the insect population. This is an alternative and cost-effective solution in integrated biological control for crop protection. Some drawbacks remain like the diffusion of active molecules in the air towards the target is not evaluated in the field due to the lack of sampling and analysis methods suitable for low levels of concentrations to be measured (a few ng/m3) (Gavara et al., 2020). To the aim, a model product developed by M2i called “Gamme Press” containing a model pheromone, the lauryl acetate, was tested in a closed emission chamber under various conditions to assess the parameters describing the release rate of pheromone from the formulation and transpose it to the field. Key parameters are the diffusion coefficient in the product (Dm), the initial emittable concentration in the product (C0), the product/air partition constant (K) and the mass transfer coefficient (hm) were determined by using two model variable volume loading (VVL) method and the C-history model (Xiong et al., 2011 a and 2011 b). The low value of C0/Ctotal (total concentration of lauryl acetate in the formulation) indicates that the parameters are determined under experimental boundary conditions, which leads to switching to open chamber tests, more representative of field conditions (greenhouse). Therefore, the adjustment of a dynamic model to greenhouse tests is considered to determine the specific emission rate of the formulation.