Evaluation of the efficiency of entomopathogenic nematodes exposed to different temperatures of vinasse in the control of Stomoxys calcitrans (Linnaeus, 1758) (Diptera: Muscidae).

Abstract

The sugarcane industry generates byproducts that contribute to the proliferation of Stomoxys calcitrans. An analysis was carried out to verify the efficacy of Heterorhabditis bacteriophora HP88 and H. baujardi LPP7 at different vinasse temperatures to control S. calcitrans larvae. Ten fly larvae were deposited in plastic containers containing four mL of 50% vinasse. Each treatment consisted of 300 EPN/larvae of H. bacteriophora added to the containers and heated at temperatures of 25, 28, 31, 34, 37 and 40 °C. The same treatments were performed using H. baujardi. The treatments were carried out in a BOD incubator at 25 ± 1 °C and 70 ± 10% RH, and each treatment was replicated six times. The treated groups, controls and temperatures showed no statistical differences in terms of larval mortality rate (P=0.8573), percentage of dead pupae (P=0.1782) and adult emergence (P=0.4386). Larval mortality rates of 30% and 14.17% were achieved with H. bacteriophora and H. baujardi, respectively, while the control groups presented 3.89% with H. bacteriophora and 8.61% with H. baujardi. From the standpoint of temperatures, significant differences were found only at 37 and 40 °C for H. baujardi. The highest pupal mortality achieved with H. bacteriophora was 34.17% at 31 °C, while that reached with H. baujardi at 37 °C was 40%. The groups containing H. bacteriophora caused lower adult emergence rates at temperatures of 25, 28, 31 and 34 °C, while H. baujardi caused its lowest emergence rates at 37 and 40 °C. It is concluded that infection occurs in the immature stages of S. calcitrans by EPN when added to 50% vinasse solution at different temperatures and that nematodes caused negative effects on the emergence of fly larvae at varying temperatures.