Population dynamics, non-crop hosts, and fruit susceptibility of Drosophila suzukii in Northeast Spain

In Northeast Spain, the invasive Drosophilidae species Drosophila suzukii has become an important agricultural pest, mainly of strawberries and cherries. To improve sustainable management practices, we conducted field surveys and laboratory trials to better understand the pest ecology, identify non-crop hosts, and assess the effect of strawberry variety and fruit ripening stage on the D. suzukii development. Our results confirmed that D. suzukii adults are active during the winter, and adult populations peaked in spring and autumn. From January to June, adult captures were female-biased, and more females had more mature eggs compared with the period of September-December. We found several non-crop hosts of this pest that are common in Mediterranean forests and margins that can provide food and reproduction resources for D. suzukii population growth. These hosts were Bryonia cretica, Prunus mahaleb, Rosa canina, Rubus ulmifolius, Sambucus nigra, Solanum chenopodioides, Solanum dulcamara, and Solanum nigrum. No-choice and choice laboratory trials demonstrated that D. suzukii was able to oviposit in red, blush, or green strawberry fruits but, host suitability of different ripeness stages varied with variety. Data provided may be useful for predicting the risk of pest damage in a specific cropping area, in designing effective D. suzukii management programs and in hindering D. suzukii population growth.