Demonstration project “Exclusion netting for managing Spotted WingDrosophila in fruit crops” – Results 2017 – 2019

Exclusion netting is a technical option to contribute to the control the invasive Spotted Wing Drosophila (SWD) Drosophila suzukii (Matsumura 1931), which has become a huge threat for European fruit crops, i. e. stone and berry fruits, since several years. Up to 22 producers of cherry, raspberry, blackberry and blueberry take part in the demonstration project, funded by the Federal Ministry of Food and Agriculture (BMEL), administrated by the Federal Office for Agriculture and Food (BLE) and coordinated by the Julius Kuehn-Institute (JKI), Institute for Plant Protection in Fruit Crops and Viticulture. Mesh sizes of the used nets varied between 0.8 x 0.8 mm and 1.3 x 1.3 mm. The various exclusion netting systems showed an overall successful reduction of fruit infestation by SWD. In orchards fully protected by netting or netting in combination with foliage a distinct reduction of the use of insecticides against SWD was possible when regular SWD monitoring and harvest sanitation procedures were conducted. There was no noticeable increase in occurrence of other pests and pathogens attributed to the nettings. However, in combination with foil tunnels, in some netted orchards an increase in spider mites and caterpillar infestation was observed. In any case, monitoring of the plants on a regular basis is advised due to exclusion of beneficial insects. Costs for the additional exclusion netting were highly variable and depended on various operational factors.