Crout Katy, Mayfield Albert, Kerrigan Julia, Hartshorn Jess
Forestry and Environmental Conservation, Clemson University, Clemson, SC, USA.
Southern Research Station, USDA Forest Service, Asheville, NC, USA.
J Econ Entomol. 2024 Dec 28;117(6):2518-2524. doi: 10.1093/jee/toae207.
The laurel wilt disease complex is a destructive combination of a non-native beetle vector [redbay ambrosia beetle (RAB), Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae)] and a symbiotic fungus (Harringtonia lauricola (Ophiostomataceae) T.C. Harr., Fraedrich & Aghayeva), which serves as a pathogen in the host trees infested by RAB. The complex originated from Asia and was first discovered in the United States near Savannah, GA in 2002, and has rapidly made its way across the southeastern US, causing mortality for redbay and other important Lauraceae species, including sassafras, giving this disease complex the potential to have far-reaching ecological effects across North America. Our goal with this study was to examine the spatial distribution of RAB attacks in redbay and sassafras trees along the leading edge of disease progression. RAB attacks were clustered in both tree species, with attacks being most concentrated on the south side of the tree in sassafras, and with RAB clustering more with other RAB attacks on redbay. When comparing bolts that produced adult RABs, the average number of RABs emerged was higher in redbay compared to sassafras. Entrance hole density, RAB emergence, and moisture content were higher near the base of the stem compared to stems sections higher on the bole of both tree species. Our results suggest that physiological differences, such as size and structure of vessels, between these tree species may drive beetle attack patterns and, therefore, affect the progression and spread of disease throughout sassafras and other Lauraceae.
月桂枯萎病复合体是由一种非本地甲虫传播媒介（红湾食菌小蠹，Xyleborus glabratus Eichhoff，鞘翅目：象甲科：小蠹亚科）和一种共生真菌（劳氏哈氏木霉，Harringtonia lauricola，长喙壳科，T.C. Harr., Fraedrich & Aghayeva）组成的具有破坏性的组合，这种真菌在被红湾食菌小蠹侵染的寄主树木中作为病原体。该复合体起源于亚洲，2002年在美国佐治亚州萨凡纳附近首次被发现，并迅速蔓延至美国东南部，导致红湾及其他重要樟科物种死亡，包括檫树，使这种病害复合体有可能在北美产生深远的生态影响。我们这项研究的目的是研究在病害蔓延前沿的红湾和檫树中红湾食菌小蠹攻击的空间分布。红湾食菌小蠹的攻击在这两种树种中都呈聚集状态，在檫树中攻击最集中在树的南侧，而在红湾中红湾食菌小蠹与其他红湾食菌小蠹攻击的聚集性更强。在比较产生成年红湾食菌小蠹的原木时，红湾中出现的红湾食菌小蠹平均数量比檫树中的更高。与两种树树干较高部位的茎段相比，茎基部附近的入口孔密度、红湾食菌小蠹出现率和含水量更高。我们的结果表明，这些树种之间的生理差异，如导管的大小和结构，可能会驱动甲虫的攻击模式，因此会影响疾病在檫树和其他樟科植物中的发展和传播。
