USDA Animal and Plant Health Inspection Service, Plant Protection and Quarantine, Science and Technology, 1398 West Truck Road, Buzzards Bay, MA 02542, USA.
Department of Environmental Biology, SUNY College of Environmental Science and Forestry, 247 Illick Hall, 1 Forestry Drive, Syracuse, NY 13210, USA.
J Econ Entomol. 2022 Oct 12;115(5):1442-1454. doi: 10.1093/jee/toac078.
Despite a robust biocontrol program against emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), parasitoid populations cannot build quickly enough to save mature ash trees. The future of ash as a viable component of North American forests depends on survival of immature ash that were too small to be attacked during the initial outbreak. This study was designed to quantify impacts of established introduced parasitoids and native woodpeckers on the population growth of emerald ash borer infesting regenerating ash saplings in white ash forests. Most emerald ash borer larvae were killed by Tetrastichus planipennisi Yang and woodpeckers in the fourth instar. Life-table analyses revealed that the estimated net reproductive rate of emerald ash borer was R0 = 4.2 in eastern New York and R0 = 0.0 in western New York. Without mortality from parasitoids and woodpeckers, R0 values would have been 16.4 and 7.9 in eastern and western New York, respectively. We monitored the health of mature and sapling ash trees from 2012 to 2017 and found that large trees were significantly more likely to be infested with emerald ash borer and to die than smaller trees. Fifty-four percent to 81% of ash saplings contained no living emerald ash borer, and the density of emerald ash borer at all sites was very low (< 4/m2). This study adds to the growing body of evidence that emerald ash borer biocontrol is contributing to population control and can help promote survival of young ash trees as forests recover from emerald ash borer outbreaks.
尽管针对灰褐天牛（Agrilus planipennis Fairmaire）（鞘翅目：扁甲科）实施了强有力的生物防治计划，但寄生蜂种群的增长速度还不够快，无法挽救成熟的灰树。灰树作为北美森林中一种可行的组成部分的未来取决于未成熟灰树的存活，这些灰树在最初的爆发期间太小而未受到攻击。本研究旨在量化已建立的引入寄生蜂和本地啄木鸟对在白蜡林中再生灰树苗上滋生的灰褐天牛种群增长的影响。大多数灰褐天牛幼虫在第四龄期被 Tetrastichus planipennisi Yang 和啄木鸟杀死。生命表分析表明，在纽约东部，灰褐天牛的估计净生殖率为 R0 = 4.2；在纽约西部，R0 = 0.0。如果没有寄生蜂和啄木鸟的死亡率，R0 值将分别为纽约东部和西部的 16.4 和 7.9。我们从 2012 年到 2017 年监测了成熟和树苗灰树的健康状况，发现大树比小树更容易受到灰褐天牛的侵袭和死亡。54%至 81%的灰树苗没有活体灰褐天牛，而且所有地点的灰褐天牛密度都非常低（<4/m2）。本研究增加了越来越多的证据，表明灰褐天牛的生物防治有助于控制种群，并有助于促进年轻灰树的生存，因为森林从灰褐天牛爆发中恢复。
