Department of Entomology and Acarology, University of Sao Paulo, Luiz de Queiroz College of Agriculture (USP/ESALQ), Piracicaba, SP, 13418-900, Brazil.
Syngenta Crop Protection, Av. Nações Unidas 18001 São Paulo, SP, Brazil.
Pest Manag Sci. 2020 Jan;76(1):169-178. doi: 10.1002/ps.5490. Epub 2019 Jun 12.
The use of Bt plants has been the main strategy for controlling the fall armyworm Spodoptera frugiperda (J. E. Smith) in Brazil. However, many resistance cases were already registered. The resistance of S. frugiperda to the Vip3Aa20 protein was recently characterized under laboratory conditions but it is still efficient under field conditions. Here, resistance monitoring studies were conducted using phenotypic (purified protein and Bt maize leaves) and genotypic (F and F screen) methods to support insect resistance management (IRM) programs and preserve Vip3Aa20 technology on maize.
Phenotypic monitoring with purified protein showed two populations significantly different from the susceptible strain on the second crop season in 2016. This number increased for the first and second crop seasons in 2017 in several regions. The genotypic monitoring estimated a mean frequency of the resistance allele of 0.0027 for the F screen and 0.0033 for the F screen. Three new resistant strains to Vip3Aa20 were selected from F screen assays. Complementation tests on these new resistant strains were positive with the previous resistant strain.
Here we showed that the resistance allele of S. frugiperda to Vip3Aa20 protein is widely distributed in maize-producing regions in Brazil and its frequency increases throughout crop seasons. © 2019 Society of Chemical Industry.
在巴西，使用 Bt 植物一直是防治秋粘虫（Spodoptera frugiperda（J. E. Smith））的主要策略。然而，已经登记了许多抗性案例。秋粘虫对 Vip3Aa20 蛋白的抗性最近在实验室条件下得到了描述，但在田间条件下仍然有效。在这里，使用表型（纯化蛋白和 Bt 玉米叶片）和基因型（F 和 F 筛选）方法进行了抗性监测研究，以支持昆虫抗性管理（IRM）计划，并保护玉米上的 Vip3Aa20 技术。
在 2016 年第二季，使用纯化蛋白进行表型监测显示有两个种群与敏感株明显不同。在 2017 年的第一季和第二季，在几个地区的数量有所增加。基因型监测估计 F 筛选的抗性等位基因频率为 0.0027，F 筛选的抗性等位基因频率为 0.0033。从 F 筛选试验中选择了三个对 Vip3Aa20 具有抗性的新菌株。对这些新的抗性菌株进行的互补试验与之前的抗性菌株均为阳性。
在这里，我们表明，秋粘虫对 Vip3Aa20 蛋白的抗性等位基因在巴西的玉米种植区广泛分布，并且其频率在整个作物季节中增加。© 2019 化学工业协会。
