Beauveria bassiana in association with genetically modified maize on Spodoptera frugiperda and Rhopalosiphum maidis management

ABSTRACT: The objective of this study work was to evaluate the efficiency of the fungusBeauveria bassiana (isolate CG 716) to controlSpoodptera frugiperda and Rhopalosiphum maidis on maize. Front this, was set up in randomized blocks split plots design, with 10 treatments and four replications. Treatments were applied to plots: B. bassiana formulated in vegetable oil at doses of 2.0, 4.0 and 6.0 x 1012 conidia ha-1, lambda-cyhalothrin (7.5 a.i. ha-1) and control (no application). Applications were made weekly. Assessments were performed before each application of the products, collecting 10 consecutive plants per plot for subsequent and storing in plastic bag from destruction of the whorl of maize and counting the number of fall armyworm larvae, aphids and natural enemies in laboratory. There were no significant differences among treatments in relation to the population ofS. frugiperda larvae and R. maidis in corn fields treated or not treated with of defensives applications, however, higher number of R. maidis was observed on the conventional cultivar at 40 days after emergence (DAE) treated with the bioinsecticide B. bassiana at a dose of 2.0 x 1012 conidia ha-1. B. bassiana associated withBt technology does not show satisfactory results to controlS. frugiperda .摘要：本研究旨在评估球孢白僵菌（Beauveria bassiana，菌株CG 716）对玉米上草地贪夜蛾（Spodoptera frugiperda）及玉米蚜（Rhopalosiphum maidis）的防治效能。为此，实验采用随机区组裂区设计（randomized blocks split plots design），设置10个处理组与4次重复。供试处理包括：以植物油为载体的球孢白僵菌制剂，施用量分别为2.0、4.0、6.0×10¹²孢子·公顷⁻¹；高效氯氟氰菊酯（lambda-cyhalothrin，有效成分用量7.5 a.i.·公顷⁻¹）；以及空白对照组（不施药）。所有处理均每周施药一次。每次施药前开展种群调查，每小区连续采集10株玉米植株，破坏玉米心叶后装入塑料袋带回实验室，统计草地贪夜蛾幼虫、蚜虫及天敌的种群数量。本研究结果显示，无论是否施用植保药剂，各处理组间玉米田草地贪夜蛾幼虫与玉米蚜的种群密度均无显著差异。但在出苗后40天（DAE，days after emergence），使用2.0×10¹²孢子·公顷⁻¹剂量的球孢白僵菌生物杀虫剂处理的常规玉米品种上，玉米蚜种群数量更高。此外，球孢白僵菌与Bt技术（Bt technology）联用对草地贪夜蛾未表现出理想的防治效果。