Technical and economic analysis of pest management practices for stored wheat in 14 grain elevators in France

Abstract: Technical audits were achieved in 14 grain elevators in order to record pest management practices and to evaluate the cost of insect control management practices. Stored grain elevators that were selected for this study were representative of the different ways of insect pest prevention and control system in France. The selection of storage sites was based on the results of a previous study led on 95 elevators that identified 6 key-factors correlated with pest infestation: type of storage bin (vertical silo or ‘flat’ store), preventive sanitation of empty storage structures, grain cleaning, grain aeration, insecticide treatment on grain, grain temperature monitoring equipment. By combining these 6 factors, 7 modalities of pest management have been described. For each modality, two grain elevators that theoretically apply each modality have been sampled among the 95 elevators surveyed in Leblanc et al. surveys in 2010 and 2011. The evaluation carried out after the visit of the selected storage facilities revealed that pest management was mainly based on chemical treatment whatever the kind of insect management system was applied. Although all the visited elevators were equipped with ambient-air aeration systems, the airflow rate and the cooling time were often found inadequate to efficiently cool all stored grain bins. Grain cleaning cannot be made systematically at reception because harvested grain lots needing cleaning are delivered at a much higher rate than the grain cleaner can receive. Pest management costs were assessed in the range 0.17 €/t to 1.19 €/t, according to the 7 modalities. The major variation factor was the type of pesticide used. The economic loss related to price penalties in the case of quality defect at the supply of domestic or export grain markets for cereals are not considered as a driving factor for insect pest management policy adaptation by grain-elevator managers.