Abstract:
An increase in Spodoptera species was reported in Bt soybean fields expressing Cry1Ac insecticidal proteins in Brazil, requiring additional management with chemical insecticides. Here, we evaluated the dose effects of flubendiamide and thiodicarb on Spodoptera cosmioides (Walker, 1858), Spodoptera eridania (Stoll, 1782), Spodoptera albula (Walker, 1857) and Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae) that survived on MON 87751 × MON 87708 × MON 87701 × MON 89788, expressing Cry1A.105, Cry2Ab2 and Cry1Ac; MON 87701 × MON 89788 soybean, expressing Cry1Ac; and non-Bt soybean. On unsprayed Cry1A.105/Cry2Ab2/Cry1Ac soybean, only S. frugiperda showed ~60% mortality after 10 d, whereas S. cosmioides, S. eridania and S. albula showed >81% mortality. The surviving larvae of all species on this Bt soybean showed >80% mortality when exposed to the field label dose of flubendiamide (70 mL/ha) or thiodicarb (400 g/ha) or at 50% of these doses. In contrast, all four species had <25% and <19% mortality on Cry1Ac and non-Bt soybean, respectively. The surviving S. cosmioides, S. eridania and S. albula on these soybean types presented >83% mortality after exposure to both dose levels of flubendiamide and thiodicarb. Some S. frugiperda larvae surviving on Cry1Ac and non-Bt soybean sprayed with a 50% dose of either insecticide developed into adults. However, the L1 larvae developing on Cry1Ac soybean leaves sprayed with flubendiamide and the L2 larvae on this soybean sprayed with thiodicarb had a prolonged immature stage, and the females displayed lower fecundity, which are likely to impact S. frugiperda population growth on soybean.
摘要:
据报道,在巴西表达Cry1Ac杀虫蛋白的Bt大豆田中,斜纹夜蛾种类有所增加,需要额外的化学杀虫剂管理。这里,我们评估了氟苯二酰胺和硫双威对斜纹夜蛾的剂量效应(Walker,1858),斜纹夜蛾(Stoll,1782),白纹夜蛾(沃克,1857年)和斜纹夜蛾(J.E.史密斯,1797)(鳞翅目:夜蛾科)在MON87751×MON87708×MON87701×MON89788上存活,表达Cry1A.105,Cry2Ab2和Cry1Ac;MON87701×MON89788大豆,表达Cry1Ac;和非Bt大豆。在未喷洒的Cry1A.105/Cry2Ab2/Cry1Ac大豆上,只有S.frugiperda在10d后显示约60%的死亡率,而S.cosmioides,S、eridania和S.albula的死亡率>81%。当暴露于田间标记剂量的氟苯二酰胺(70mL/ha)或硫双威(400g/ha)或这些剂量的50%时,该Bt大豆上所有物种的存活幼虫均显示>80%的死亡率。相比之下,所有四个物种对Cry1Ac和非Bt大豆的死亡率均<25%和<19%,分别。幸存的棉菌,S.eridania和S.albula对这些大豆类型的暴露于两种剂量水平的氟苯二酰胺和硫双威后,死亡率>83%。一些在Cry1Ac和非Bt大豆上存活的S.frugiperda幼虫喷洒了50%剂量的两种杀虫剂后发育成成虫。然而,在喷洒氟苯二酰胺的Cry1Ac大豆叶片上发育的L1幼虫和喷洒硫双威的该大豆上的L2幼虫的未成熟期延长,雌性的繁殖力较低,这可能会影响大豆的节俭链球菌种群增长。