Optimising biological control in greenhouse crops in SE Spain through habitat adaptations and increase of biodiversity

Abstract: IPM, based on biological control through beneficial arthropods, is implemented in,
approximately, 82 % of the greenhouse food-crops in SE Spain. This includes over 95 % of
sweet pepper, tomato, and aubergine crops, and somewhat less in cucurbits. Biological control is based on inoculative Biological Control Agent (BCA) releases, but an increasingly important role is recognised to be provided by naturally occuring beneficial fauna. This motivates growers to take conservation measures, to favour the arrival and settlement of this fauna. Improvements of the habitat for BCA’s consist in a certain level of climate control, to avoid extreme temperatures and relative humidity in the warmer months of the year, and in diversification of the vegetation in and around the greenhouses to create additional resources for BCA’s. Three types of auxiliary, non-crop, plant types can be distinguished: a) banker plants with abundant flowering, offering nectar and pollen as food for a wide range of species; b) banker plants with alternative prey for BCA’s in the form of species that cannot live on the crop; c) ‘trapping plants’, i. e., which are particularly attractive for pests that may otherwise harm the crop. The latter may serve as sentinel plants and/or offer a possibility to concentrate BCA releases.
In spring 2022, a survey concerning the adoption of agroecological measures was carried
out amongst, 534 greenhouse growers in Almería-Granada. Most of the data presented below
are derived from this survey.