Microclimates in greenhouse IPM: Linking abiotic variation to biocontrol efficacy

Abstract: Greenhouses vary in physical structure and technologies for active climate control
that together shape the abiotic growing environment. Designing greenhouses for optimal plant productivity is a top priority for greenhouse producers, and how these choices influence pest risk and pest management efficacy is less clear. This presentation will demonstrate how climate variation among greenhouses and microclimates within greenhouses impact pest populations and efficacy of macro and micro biological control tools for their management. The choice of covering alone had a significant impact on UV radiation in protected strawberry systems that impacted invertebrate community assembly and the and efficacy of microbial biocontrol sprays. Our recent research also demonstrated significant variation in light intensity, temperature, and relative humidity between similarly structured greenhouses with HPS or LED supplemental light fixtures. The choice of light fixture therefore was a significant driver of climate variation between greenhouses. Distance to HPS fixtures was positively correlated with increased temperature on the leaf surface that was further linked to higher two-spotted spider mite pressure and reduced efficacy of biocontrol applications. These findings suggest that decisions regarding greenhouse design and climate control represent important IPM strategies for building more resilient greenhouse production systems.