Dispersal and maintenance of Neoseiulus cucumeris and Amblyseius swirskii (Acari: Phytoseiidae) to control thrips in greenhouse crops as influenced by micro habitat environment

The present study aimed to investigate the effect of microclimate parameters within the plant cover as well as their effects on dispersal of the bioagents Neoseiulus cucumeris Oudemans and Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) at the plant level. It was a preliminary step to microclimate control in order to increase the bioagent efficacy. Effect of humidity was studied in priority, as it seems to have a preponderant role. It consisted in monitoring the dispersal of bioagents in parallel with microclimatic heterogeneity characterization at the plant level. The results highlighted that (i) the climatic parameters varied spatially within the plant according to the level: (ii) At high relative humidity, one week after release, both predators; A. swirskii and N. cucumeris showed a density increase on the plant, while under dry conditions the contrary occurred, and (iii) High humidity was suitable for both predators.