Suscetibilidade de populações dos dípteros Anastrepha fraterculus, Ceratitis capitata (Tephritidae) e Drosophila suzukii (Drosophilidae) a inseticidas e efeitos transgeracionais sobre o himenóptero Trichopria anastrephae (Diapriidae)

Abstract

Among the most important pest arthropods in Brazilian fruit production are fruit flies (Diptera: Tephritidae), with emphasis on Anastrepha fraterculus Wiedemann, 1830 and Ceratitis capitata Wiedemann, 1824. However, as of 2014, Drosophila suzukii Matsumura, 1931 (Diptera: Drosophilidae) gained status as the main pest of fine tegument fruits, due to the ability of females to pierce intact fruits for oviposition. For the three species, chemical control with the use of synthetic insecticides is the most widely used field management strategy. In view of the high number of applications (from 4 to 6 per harvest), concerns arise about the effects generated on the beneficial entomofauna and the probability of evolution of resistance to insecticides. In view of this, the objective of the present study was to know the susceptibility of populations geographically distinct from A. fraterculus, C. capitata and D. suzukii to insecticides, as well as to evaluate the lethal, sublethal and transgenerational effects of insecticides on the parasitoid Trichopria anastrephae Costa Lima, 1940 (Hymenoptera: Diapriidae), considered the main pupal parasitoid of D. suzukii in Brazil. Through ingestion bioassays using a susceptible reference population of A. fraterculus, C. capitata and D. suzukii, lethal concentrations (LC50 and LC90) and diagnostic concentrations (based on the values of LC99) of different insecticides were defined. For the susceptible population of A. fraterculus, the insecticides had low LC50 values in relation to susceptibility to lambda-cyhalothrin (6.34 µg ia / mL), malationa (6.54 µg ia / mL) and spinosad (8.76 µg ai / mL). The susceptible population of C. capitata laboratory had a similar response in lethal concentration (LCs), being spinosad (1.30 µg ia / mL), spinetoram (2.76 µg ia / mL) and malationa (7.10 µg ia / mL), however significantly higher LCs were found for lambda-cyhalothrin (76.55 µg ai / mL). Likewise, the LC50 values for deltamethrin (0.67 µg ia / mL), malationa (3.30 µg ia / mL), spinosad (4.16 µg ia / mL), spinetoram (4.75 µg ia / mL) were lower for the susceptible population of D. suzukii than abamectin (15.02 µg ia / mL), acetamiprid (39.38 µg ia / mL) and thiamethoxam (70.15 µg ia / mL). The diagnostic concentrations of each insecticide cause mortality greater than 90% for the three species, suggesting a low interpopulation variation in susceptibility. When evaluating the lethal, sublethal toxicity and the transgenerational effects of the insecticides abamectin, deltamethrin, malationa, espinetoram and thiametoxam on adults of T. anastrephae during the F0, F1 and F2 generations, it was verified that in the F0 generation, malationa was the only insecticide that caused 100% mortality of the parasitoids. However, all insecticides evaluated affected the rate of parasitism, being classified as moderately and slightly harmful. In the F1 generation of the parasitoid, emergence was also affected, classifying the insecticides malationa, deltamethrin, spinetoram and thiamethoxam as moderately to slightly harmful. However, the insecticide abamectin was classified as harmless. In the F2 generation, the insecticides evaluated did not cause negative effects on the parasitoid T. anastrephae and were classified as harmless. The defined diagnostic concentrations can be used in resistance monitoring programs in Brazil. As well, in order to establish a MIP program, knowledge of the toxicity of insecticides to the parasitoid T. anastrephae is essential to maintain the sustainability of the management system.