Forty years of biological control in Mediterranean tomato greenhouses: The story of success

The article highlights major landmarks in the development of Integrated Pest Management (IPM) programmes for tomato greenhouses in the Mediterranean region. This is the story of how biological control has been succesfully implemented as a cornerstone of IPM programmes in Catalonia (Northeastern Spain), one of the pioneering areas in the Mediterranean basin for the implementation of biological control in greenhouses. In the 1970s, Trialeurodes vaporariorum (Hemiptera: Aleyrodidae) was the key pest in the area and first programmes in protected tomato crops were based on inoculative releases of the parasitoid Encarsia formosa (Hymenoptera: Aphelinidae). However, failures caused by the expansion of Encarsia pergandiella (Hymenoptera: Aphelinidae) and the increasing importance of Bemisia tabaci (Hemiptera: Aleyrodidae) propitiated the change to use heteropterans of the Miridae family as biocontrol agents. These generalist predators were already observed during the first trials in the 1970s, but their use was not widespread until B. tabaci and the South American tomato pinworm Tuta absoluta (Lepidoptera: Gelechiidae) became serious problems. Despite scepticism of many IPM practitioners about the usefulness of these generalist natural enemies, mirid predators are currently widely used for protecting Mediterranean tomato crops. Papers on the biology, behaviour and ecology of the Miridae have gained importance in the scientific literature published over the last 35, which undoubtedly has promoted their inclusion in IPM programmes. The activities of the IOBC/WPRS Working Group “Integrated Control in Protected Crops, Mediterranean Climate” has had a major impact on the progress of biological control strategies in Mediterranean tomato greenhouses over last decades. KEYWORDS: Biological control, generalist predators, parasitoids, whiteflies, tomato, Mediterranean, greenhouse farming.