Insect excluding mesh enhances Spotted-wing Drosophila (Drosophila suzukii) control in tunneled raspberry with limited effects on natural enemy abundance

Abstract

Spotted-wing Drosophila (Drosophila suzukii) oviposits in a wide range of soft and stone fruit, which can result in a reduction of fruit quality and yield. An invasive, polyphagous species, D. suzukii targets ripe fruit, such as raspberries, which are commonly grown in polytunnels. With increasing restriction on the use of agrochemicals, effective alternative approaches to D. suzukii are needed. We assessed the impacts of insect mesh on D. suzukii abundance and oviposition in tunnel-grown raspberries, as well as how it impacts the abundance of other pests and natural enemies, fruit quality and tunnel microclimate. Drosophila suzukii abundance in traps was lower in mesh tunnels compared to adjacent non-crop areas although no significant difference between mesh and control tunnels was observed. Although D. suzukii emergence from harvested fruit was significantly lower on fruit collected in mesh tunnels compared to control tunnels. Mesh impacted sooty shoulder coverage of fruit and had only limited impacts on the abundance of natural enemies such as ants, spiders and parasitic wasps while increasing instances of peak temperature and humidity were found. We highlight the varying impacts mesh netting has on soft fruit production and discuss how these findings can be used to help incorporate insect mesh into IPM strategies to effectively control D. suzukii.