Orange jasmine as a trap crop to control Diaphorina citri

Abstract

Novel, suitable and sustainable alternative control tactics that have the potential to reduce migration of Diaphorina citri into commercial citrus orchards are essential to improve management of huanglongbing (HLB). In this study, the effect of orange jasmine (Murraya paniculata) as a border trap crop on psyllid settlement and dispersal was assessed in citrus orchards. Furthermore, volatile emission profiles and relative attractiveness of both orange jasmine and sweet orange (Citrus × aurantium L., syn. Citrus sinensis (L.) Osbeck) nursery flushes to D. citri were investigated. In newly established citrus orchards, the trap crop reduced the capture of psyllids in yellow sticky traps and the number of psyllids that settled on citrus trees compared to fallow mowed grass fields by 40% and 83%, respectively. Psyllids were attracted and killed by thiamethoxam-treated orange jasmine suggesting that the trap crop could act as a ‘sink’ for D. citri. Additionally, the presence of the trap crop reduced HLB incidence by 43%. Olfactometer experiments showed that orange jasmine plays an attractive role on psyllid behavior and that this attractiveness may be associated with differences in the volatile profiles emitted by orange jasmine in comparison with sweet orange. Results indicated that insecticide-treated M. paniculata may act as a trap crop to attract and kill D. citri before they settled on the edges of citrus orchards, which significantly contributes to the reduction of HLB primary spread.