Centro de Estudios de Investigaciones, Universidad Nacional de Quilmes, Bernal, Buenos Aires, Argentina.
Curr Microbiol. 2011 Sep;63(3):250-8. doi: 10.1007/s00284-011-9944-y. Epub 2011 Jul 8.
Leaf-cutting ants are one of the main herbivores of the Neotropics, where they represent an important agricultural pest. These ants are particularly difficult to control because of the complex network of microbial symbionts. Leaf-cutting ants have traditionally been controlled through pesticide application, but there is a need for alternative, more environmentally friendly, control methods such as biological control. Potential promising biocontrol candidates include the microfungi Escovopsis spp. (anamorphic Hypocreales), which are specialized pathogens of the fungi the ants cultivate for food. These pathogens are suppressed through ant behaviors and ant-associated antibiotic-producing Actinobacteria. In order to be an effective biocontrol agent, Escovopsis has to overcome these defenses. Here, we evaluate, using microbial in vitro assays, whether defenses in the ant-cultivated fungus strain (Leucoagaricus sp.) and Actinobacteria from the ant pest Acromyrmex lundii have the potential to limit the use of Escovopsis in biocontrol. We also explore, for the first time, possible synergistic biocontrol between Escovopsis and the entomopathogenic fungus Lecanicillium lecanii. All strains of Escovopsis proved to overgrow A. lundii cultivar in less than 7 days, with the Escovopsis strain isolated from a different leaf-cutting ant species being the most efficient. Escovopsis challenged with a Streptomyces strain isolated from A. lundii did not exhibit significant growth inhibition. Both results are encouraging for the use of Escovopsis as a biocontrol agent. Although we found that L. lecanii can suppress the growth of the cultivar, it also had a negative impact on Escovopsis, making the success of simultaneous use of these two fungi for biocontrol of A. lundii questionable.
切叶蚁是新热带地区的主要草食动物之一，也是重要的农业害虫。这些蚂蚁由于其复杂的微生物共生网络而特别难以控制。传统上，切叶蚁通过农药施用进行控制，但需要替代的、更环保的控制方法，如生物防治。潜在的有希望的生物防治候选物包括微真菌 Escovopsis spp.（无性态 Hypocreales），它们是蚂蚁为食物而培养的真菌的专性病原体。这些病原体通过蚂蚁行为和蚂蚁相关的产生抗生素的放线菌被抑制。为了成为有效的生物防治剂，Escovopsis 必须克服这些防御。在这里，我们使用微生物体外测定法评估，蚂蚁所培养的真菌菌株（Leucoagaricus sp.）和来自 Acromyrmex lundii 的放线菌的防御是否有可能限制 Escovopsis 在生物防治中的使用。我们还首次探索了 Escovopsis 与昆虫病原真菌 Lecanicillium lecanii 之间可能的协同生物防治。所有 Escovopsis 菌株都在不到 7 天的时间内超过了 A. lundii 品种的生长，而从不同的切叶蚁物种中分离出的 Escovopsis 菌株最为有效。Escovopsis 受到从 A. lundii 分离出的链霉菌菌株的挑战时，没有表现出明显的生长抑制。这两个结果都为 Escovopsis 作为生物防治剂的使用提供了希望。尽管我们发现 L. lecanii 可以抑制品种的生长，但它也对 Escovopsis 产生了负面影响，使得同时使用这两种真菌来防治 A. lundii 的生物防治的成功值得怀疑。
