Laboratory trials to investigate potential repellent/oviposition deterrent effects of selected substances on Drosophila suzukii adults

Drosophila suzukii (Matsumura) (Diptera Drosophilidae), commonly named spotted wing drosophila, is a highly polyphagous invasive pest from Asia, causing large economic losses in soft and stone fruit production. To prevent D. suzukii from ovipositing into host fruits four essential oils (neem oil, patchouli oil, celery oil and catnip oil) as well as single components of two other essential oils (p-menthane-3,8-diol and 3-butylidenephthalide) were tested at two different concentrations for their repellent and/or oviposition deterrent effects on D. suzukii in laboratory trials on raspberries. A no-choice test assay in modified Hesler-plates employing seven 8-10 days old D. suzukii per treatment was carried out for each treatment. Flies were allowed to oviposit for 24 hours on 3 raspberries/test unit and were examined 72 hours later for the presence of larval instars. Only the treatments with neem oil at 1% and p-menthane-3,8-diol at 1% and 10% significantly reduced the mean number of D. suzukii larvae/fruit compared to the control