Department of Entomology, Louisiana State University, Baton Rouge, LA, USA.
Hammond Research Station, Louisiana State University Agricultural Center, Hammond, LA, USA.
J Invertebr Pathol. 2022 Sep;193:107789. doi: 10.1016/j.jip.2022.107789. Epub 2022 Jun 27.
Insect predators are the most important natural enemies of the crapemyrtle bark scale (CMBS) in the USA. Mycopesticides (biocontrol fungi) are considered an IPM tool to increase CMBS mortality; however, their impacts on CMBS predators are unknown. The objectives of this study were to assess the abundance and diversity of CMBS natural enemies in Louisiana; evaluate the impacts of mycopesticides on survival of CMBS predators by life stage; and determine if entomopathogenic spores delivered to crapemyrtles are transferred to predators under field conditions. The mycopesticides Ancora® (Isaria fumosorosea PFR97), BioCeres® (Beauveria bassiana ANT-03), and BotaniGard® (B. bassiana GHA) were tested against the coccinellids Chilocorus spp. and Hyperaspis bigeminata under laboratory and field conditions. Adults and larvae of the coccinellids were treated with each mycopesticide and survival recorded over a 14-day period. The most common natural enemies on CMBS infested trees were the coccinellids Chilocorus cacti, C. stigma, and Hyperaspis bigeminata (Coleoptera: Coccinellidae). In laboratory bioassays BotaniGard® reduced survival of adults and larvae of both genera by at least 57%. BioCeres® reduced the survival of Chilocorus spp. adults by 40% and Ancora® reduced survival of H. bigeminata larvae by 69%. Under field conditions, CMBS infestations were sprayed with the mycopesticides and coccinellids were collected every other day for a two-week period. Spores of the applied mycopesticides were recovered from the coccinellids; however, it is not known if infection occurred in the field trial or spores were delivered to CMBS infestations by the coccinellids. We conclude that mycopesticides negatively impacted the survival of coccinellids in laboratory trials, and coccinellids can transport pathogen spores under field conditions.
昆虫捕食者是美国紫薇树皮鳞（CMBS）最重要的天敌。生防真菌（生物防治真菌）被认为是增加 CMBS 死亡率的 IPM 工具；然而，它们对 CMBS 捕食者的影响尚不清楚。本研究的目的是评估路易斯安那州 CMBS 天敌的丰度和多样性；评估生防真菌对 CMBS 捕食者各生活阶段存活率的影响；并确定在田间条件下，施用于紫薇上的昆虫病原真菌孢子是否会转移到捕食者身上。生防真菌 Ancora®（Isaria fumosorosea PFR97）、BioCeres®（Beauveria bassiana ANT-03）和 BotaniGard®（B. bassiana GHA）在实验室和田间条件下针对鞘翅目瓢虫科的 Chilocorus spp. 和 Hyperaspis bigeminata 进行了测试。用每种生防真菌处理瓢虫的成虫和幼虫，并在 14 天内记录存活率。在受 CMBS 感染的树上最常见的天敌是鞘翅目瓢虫科的 Chilocorus cacti、C. stigma 和 Hyperaspis bigeminata。在实验室生物测定中，BotaniGard®至少降低了两种属的成虫和幼虫的存活率 57%。BioCeres®降低了 Chilocorus spp. 成虫的存活率 40%，Ancora®降低了 H. bigeminata 幼虫的存活率 69%。在田间条件下，用生防真菌喷洒 CMBS 感染的树木，每隔一天收集一次瓢虫，持续两周。从瓢虫身上回收了施用的生防真菌的孢子；然而，尚不清楚在田间试验中是否发生了感染，或者孢子是否通过瓢虫被输送到 CMBS 感染区。我们得出结论，生防真菌在实验室试验中对瓢虫的存活率产生了负面影响，并且在田间条件下，瓢虫可以运输病原菌孢子。
