Potencial de nematoides entomopatogênicos para controle de Drosophila suzukii (Diptera: Drosophilidae

Abstract

Drosophila suzukii (Matsumura, 1931) represents one of the main plagues associated with the production of small fruits in Brazil. It is popularly known by preference towards fragile integument fruits and causing large damage to fruit harvesting. The use of biological agents shows to be very promising in controlling the insect, this way the goal of this work was to evaluate the potential of nematodes in different concentrations and temperatures over the mortality of D. suzukii pupae and effects on its adults' longevity. Bioassays were divided into 3 steps, Steinernema rarum PAM 25 and Steinernema glaseri J1 pathogenicity test, in the concentration of 1000 infective juveniles, inoculated in 5 pupae of Drosophilia suzukii (MATSUMURA 1931) with approximately 48 hours of age, the experiment was constituted by plastic recipients (200 mL) containing 50g of dry sand and autoclaved with 5% humidity, stored in BODs at 25ºC, 80% RH, 12 hours photoperiod. In the second bioassay, we evaluated the influence of concentration and temperature on D. suzukii mortality. The experiment counted six treatments (1500, 2000, 2500, 3000 and 4000) with 10 repetitions on 14, 22 and 25 ºC of temperature. In the third bioassay, we evaluated the influence of presence on isolation and it’s pathogenicity on an adult’s life. For this experiment, we used the concentration with the highest mortality rate for each temperature which are, 14ºC 4000 IJs/mL, 22ºC 1500 IJs/mL, 25ºC 2000 Ijs/mL. For both experiments, the control was constituted with the same settings, though, without nematodes. The evaluations were realized on a daily basis for seven days after the inoculation. The infected adults with S. rarum PAM 25 presented a longevity average of 5.18 days at 14ºC, 6.26 days at 22 ºC and 6.79 days at 25ºC. There was a significate difference between the control groups in all temperatures, although there is no difference if compared to each other.