Lemes Amanda A F, Sipriano-Nascimento Thamiris P, Vieira Natalia F, Cardoso Camila P, Vacari Alessandra M, De Bortoli Sergio A
Laboratory of Biology and Insect Rearing (LBIR), Department of Plant Protection, São Paulo State University FCAV-Unesp, Jaboticabal, São Paulo, Brazil.
Science and Animal Science Graduate Program, University of Franca Unifran, Franca, São Paulo, Brazil.
J Econ Entomol. 2021 Feb 9;114(1):298-306. doi: 10.1093/jee/toaa260.
The diamondback moth, Plutella xylostella (Linnaeus, 1758), is one of the main pests of brassicas, and various insecticides, such as indoxacarb, are used to control it. However, frequent insecticide applications favor the selection of resistant individuals. Thus, the residual and sublethal effects of indoxacarb in two populations of P. xylostella, one collected in the field (FP) and one from the laboratory (LP), were evaluated and compared. The objective of this research was to investigate the toxicity of indoxacarb at residual and sublethal levels in a field population of P. xylostella from Brazil and a population from the laboratory. Leaf-dip bioassays showed high toxicity, with LC50 values after 48 h of 3.7 and 6.9 mg/liter for the LP and FP, respectively. Sublethal effects were indicated by significant reduction in the survival of larvae, pupae, and offspring. There was an increase in foliar consumption and a decrease in adult survival in the LP, and a decrease in fecundity in the FP. For the LP and FP population, the mean values for R0, rm, and λ for the control treatment were significantly higher than for the treatment groups (CL15 and CL25). Exposure of larvae to sublethal indoxacarb concentrations significantly reduced larval and pupal survival. Larval and pupal survival decreased as the indoxacarb concentration increased. Fecundity was significantly lower for the FP at LC15 (96.2 eggs per female) and LC25 (69.2 eggs per female) concentrations compared with the other treatments.
小菜蛾，即菜蛾（林奈，1758年），是十字花科蔬菜的主要害虫之一，人们使用多种杀虫剂（如茚虫威）来防治它。然而，频繁使用杀虫剂有利于抗性个体的选择。因此，对茚虫威在小菜蛾的两个种群中的残留和亚致死效应进行了评估和比较，其中一个种群采自田间（FP），另一个来自实验室（LP）。本研究的目的是调查茚虫威在巴西田间小菜蛾种群和实验室种群中的残留和亚致死水平的毒性。浸叶生物测定显示出高毒性，48小时后LP和FP的LC50值分别为3.7和6.9毫克/升。亚致死效应表现为幼虫、蛹和后代的存活率显著降低。LP中叶片消耗量增加，成虫存活率降低，FP中繁殖力降低。对于LP和FP种群，对照处理的R0、rm和λ的平均值显著高于处理组（CL15和CL25）。将幼虫暴露于亚致死浓度的茚虫威中会显著降低幼虫和蛹的存活率。幼虫和蛹的存活率随着茚虫威浓度的增加而降低。与其他处理相比，FP在LC15（每雌虫96.2粒卵）和LC25（每雌虫69.2粒卵）浓度下的繁殖力显著较低。
