Dinâmica populacional de Drosophila suzukii (Diptera: Drosophilidae) no sul do Rio Grande do Sul

Abstract

Drosophila suzukii Matsumura (Diptera: Drosophilidae), the spotted wing drosophila is an exotic pest economically important in the world in production systems soft skinned fruit. In Brazil, the southern region stands out in the production of small fruits and constitutes one of the areas of greater environmental adequacy for this species, identified in the country in 2013. This study aimed to monitor the activity of D. suzukii in commercial cultivations of blackberry, blueberries, strawberry guava, Surinam cherry and strawberry using baited traps with apple cider vinegar; to study the preference and the natural infestation rates (fly/fruit and fly/kg of biomass) of D. suzukii in fruits from monitored orchards; to evaluate the efficiency of the food substrates Ceratrap®, Torula®, Biofruit®, Suzukii Trap®, apple cider vinegar and a mixture of red wine, apple cider vinegar and molasses (WVM) in fly attractiveness in blackberry orchard; and to verify the occurrence of natural enemies with potential of parasitism over D. suzukii in berries and strawberry fruits. The experiments were carried out from April 2015 to April 2017, totalizing two consecutive years for the first two studies, and in discontinuous periods for the other experiments, and were conducted in four properties located in the south of Rio Grande do Sul. Monitoring showed that the highest activity of D. suzukii occurred between late spring and mid-autumn, and the capture of insects was significantly influenced by temperature and humidity at all seasons. The highest rates of natural infestation and preference were seen in blackberry fruits (40 to 65% of infestation) and strawberries (about 30% of infestation), and blueberry fruits were less preferred (less than 7% of infestation) by D. suzukii. The WVM mixture was the attractant that showed the greatest efficiency in the capture of D. suzukii adults (61.97% of the captured insects), and the attractants Suzukii Trap®(17.6%) and apple cider vinegar (5.4%) were the most selective products to non-target insects. The potential agents of biotic mortality recovered from fruits of blackberry and strawberry attacked by D. suzukii were the parasitoids Leptopilina boulardi (Barbotin, Carton & Kelner-Pillault) (Hymenoptera: Figitidae) and Trichopria anastrephae Lima (Hymenoptera: Diapriidae)