Yang Xiuhao, Henderson Gregg, Mao Lixin, Evans Ahmad
Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA; Department of Forest Pest Management, Forestry Administration of Guangxi Province, Nanning 530022, China.
Environ Entomol. 2009 Aug;38(4):1241-9. doi: 10.1603/022.038.0435.
A ground penetrating radar (GPR) technique was used to detect Formosan subterranean termite (Coptotermes formosanus) and red imported fire ant (Solenopsis invicta) hazards and risks (targets) in a soil levee at the London Avenue Canal in New Orleans, LA. To make this assessment, GPR signal scans were examined for features produced by termite or ant activities and potential sources of food and shelter such as nests, tree roots, and voids (tunnels). The total scanned length of the soil levee was 4,125 m. The average velocity and effective depth of the radar penetration was 0.080 m/ns and 0.61 m, respectively. Four hundred twenty-seven targets were identified. Tree roots (38), voids (31), fire ant nests (209), and metal objects (149) were detected, but no Formosan termite carton nests were identified. The lack of identified termite nests may be related to drowning events at the time to the flood. Based on the target density (TD), the two new floodwall and levee sections that were rebuilt or reinforced after they were destroyed by Hurricane Katrina in 2005 were determined to be at low potential risk from termites and ants. A merging target density (MTD) method indicated a high potential risk near one of the breached sections still remains. Foraging and nesting activity of Formosan subterranean termites and red imported fire ants may be a contributory factor to the levee failure at the London Avenue Canal.
采用探地雷达（GPR）技术，对路易斯安那州新奥尔良市伦敦大道运河一处土堤中台湾乳白蚁（Coptotermes formosanus）和红火蚁（Solenopsis invicta）的危害及风险（目标物）进行检测。为进行此项评估，对GPR信号扫描结果进行检查，寻找由白蚁或蚂蚁活动产生的特征以及潜在的食物和庇护来源，如巢穴、树根和空洞（隧道）。土堤的总扫描长度为4125米。雷达穿透的平均速度和有效深度分别为0.080米/纳秒和0.61米。共识别出427个目标物。检测到树根（38个）、空洞（31个）、红火蚁巢穴（209个）和金属物体（149个），但未识别出台湾乳白蚁的纸质巢。未识别出白蚁巢可能与当时洪水造成的淹没事件有关。根据目标密度（TD），2005年被卡特里娜飓风摧毁后重建或加固的两段新防洪墙和土堤被确定遭受白蚁和蚂蚁侵害的潜在风险较低。一种合并目标密度（MTD）方法表明，其中一个决口段附近仍存在高潜在风险。台湾乳白蚁和红火蚁的觅食和筑巢活动可能是伦敦大道运河土堤决堤的一个促成因素。
