Hajian-Forooshani Zachary, Rivera Salinas Iris Saraeny, Jiménez-Soto Estelí, Perfecto Ivette, Vandermeer John
Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109 (
Present address: Natural Science Building 830 N. University Ave. Room 2081, Ann Arbor, MI 48109.
Environ Entomol. 2016 Dec;45(6):1521-1526. doi: 10.1093/ee/nvw125. Epub 2016 Oct 15.
Recent theoretical work suggests that two ineffective control agents can provide effective biological control when coupled together. We explore the implications of this work with the system of coffee leaf rust (CLR), caused by the fungal agent Hemileiae vastatrix, and two of its natural enemies, a fungal pathogen (Lecanicillium lecanii) and a spore predator (Mycodiplosis hemileiae). Here we report on comparative surveys of the CLR and its two natural enemies in Mexico, where the CLR has been at epidemic status since 2012, and Puerto Rico, where the CLR is present but has not reached epidemic densities. We found that the densities of the two control agents per CLR lesion is higher in Puerto Rico than in Mexico, and we hypothesize that their joint presence at higher densities is contributing to the suppression of the CLR in Puerto Rico but not in Mexico. Furthermore, we found that the presence of Azteca sericeasur, a keystone ant species that occurs in Mexico but not Puerto Rico, significantly reduces the prevalence of M. hemileiae on coffee plants. Our work provides data that allows us to hypothesize that the joint presence of these two control agents may potentially provide control of the CLR and also highlights the importance of regionally specific communities within agroecosystems, and how variation in community composition may lead to varying outcomes for biological control. Additionally, this is the first report of the presence of a potentially important biological control agent, M. hemileiae, in Latin America and the Caribbean.
近期的理论研究表明，两种低效的控制剂联合使用时可实现有效的生物防治。我们以咖啡叶锈病（CLR）系统为例探讨了该研究成果的意义，咖啡叶锈病由真菌病原体咖啡驼孢锈菌引起，其有两种天敌，一种是真菌病原体（蜡蚧轮枝菌），另一种是孢子捕食者（咖啡盘二孢菌）。在此，我们报告了对墨西哥和波多黎各的咖啡叶锈病及其两种天敌的比较调查结果，自2012年以来墨西哥的咖啡叶锈病一直处于流行状态，而波多黎各虽有咖啡叶锈病，但尚未达到流行密度。我们发现，每个咖啡叶锈病病斑上两种控制剂的密度在波多黎各高于墨西哥，我们推测它们在波多黎各以更高密度共同存在有助于抑制咖啡叶锈病，而在墨西哥则不然。此外，我们发现墨西哥特有的关键蚂蚁物种丝光褐蚁的存在显著降低了咖啡盘二孢菌在咖啡植株上的发生率。我们的研究提供了数据，使我们能够推测这两种控制剂的共同存在可能会有效控制咖啡叶锈病，同时也凸显了农业生态系统中区域特定群落的重要性，以及群落组成的差异如何导致生物防治产生不同结果。此外，这是拉丁美洲和加勒比地区首次报告存在一种潜在重要的生物防治剂——咖啡盘二孢菌。
