Garrido-Jurado I, Resquín-Romero G, Yousef-Naef M, Ríos-Moreno A, Quesada-Moraga E
Department of Agronomy, ETSIAM, University of Cordoba, Campus de Rabanales, Edificio C4 Celestino Mutis, 14071 Cordoba, Spain.
Area of Plant Protection, Faculty of Agrarian Sciences of the National University of Asunción, San Lorenzo, Paraguay.
Bull Entomol Res. 2020 Apr;110(2):242-248. doi: 10.1017/S000748531900052X. Epub 2019 Sep 27.
Four Beauveria bassiana and three Metarhizium brunneum isolates were evaluated, as soil drenches, against Spodoptera littoralis prepupae. Treatment efficacy was determined by assessing total mortality during development from prepupae through to pupae and adults; mortality and sub-lethal effects on reproduction were also quantified for adults emerging from surviving prepupae/pupae. All isolates were pathogenic but overall mortality varied between 31.7 and 83.3% (0% for control); average survival time was 7.5-10.5 days (14.0 days for control). From 1.7-15.0% of adults emerging from surviving prepupae/pupae were deformed (0% in control). Contact with fungal suspensions as prepupae/pupae caused a significant reduction in fecundity of emerging adult females (15-58.9%), and a significant reduction in egg viability (6.8-28.4%) compared with controls. Two isolates were selected for virulence evaluation against S. littoralis prepupae. The LC50s were 1.7 × 107 and 1.8 × 107 conidia ml-1 and the median survival times were 7 and 6 days for isolates EAMa 01/58-Su and EAMb 09/01-Su, respectively. Destruxin A was present in pupae developing from prepupae treated with isolates EAMa 01/58-Su (0.010 ± 0.002 µg pupae-1) and EAMb 09/01-Su (0.015 ± 0.003 µg pupae-1). The use of entomopathogenic fungi as soil drenches could be a key component of S. littoralis IPM strategies due to direct reductions in the number of soil-dwelling life stages and, also, the significant reduction in reproductive potential of surviving adults.
对4株球孢白僵菌（Beauveria bassiana）和3株布氏绿僵菌（Metarhizium brunneum）分离株进行了评估，将其作为土壤浇灌剂用于防治滨海灰翅夜蛾（Spodoptera littoralis）预蛹。通过评估从预蛹发育至蛹和成虫阶段的总死亡率来确定处理效果；还对从存活的预蛹/蛹羽化出的成虫的死亡率和对繁殖的亚致死效应进行了量化。所有分离株均具有致病性，但总体死亡率在31.7%至83.3%之间（对照为0%）；平均存活时间为7.5 - 10.5天（对照为14.0天）。从存活的预蛹/蛹羽化出的成虫中有1.7% - 15.0%出现畸形（对照为0%）。预蛹/蛹期接触真菌悬浮液导致羽化出的成年雌虫的繁殖力显著降低（15% - 58.9%），且与对照相比，卵的活力显著降低（6.8% - 28.4%）。选择了2株分离株对滨海灰翅夜蛾预蛹进行毒力评估。分离株EAMa 01/58 - Su和EAMb 09/01 - Su的半数致死浓度（LC50）分别为1.7×10^7和1.8×10^7分生孢子/毫升，中位存活时间分别为7天和6天。在用分离株EAMa 01/58 - Su（0.010±0.002微克/蛹）和EAMb 09/01 - Su（0.015±0.003微克/蛹）处理的预蛹发育而成的蛹中存在白僵菌素A。由于能直接减少土壤中各虫态的数量，并且显著降低存活成虫的繁殖潜力，将昆虫病原真菌作为土壤浇灌剂可能是滨海灰翅夜蛾综合防治策略的关键组成部分。
