Area-wide evaluation of bait density and cost-effectiveness in the elimination of the Formosan subterranean termite

Abstract

Area-wide (AW) termite management based on baiting has been proven to be effective for controlling subterranean termites. The density and distribution of bait stations strongly influence the cost-effectiveness of AW programs. To evaluate optimal bait density, we conducted a 2-year baiting program in Central Taiwan Science Park (466 ha) and Hsinchu Science Park (777 ha), Taiwan. In 6 study plots, Formosan subterranean termite (FST, Coptotermes formosanus Shiraki) colony activity was monitored using a 5-m spaced wood stake matrix with monthly inspections. Each colony was baited with a single in-ground bait station. A total of 11 colonies were eliminated, with a mean elimination time of 1.82 ± 1.25 months and bait consumption of 164.3 ± 68.6 g (∼1 bait tube) per colony. Based on empirical data, including baiting processes, colony territory size, and landscape features, we simulated bait station spacings (6 to 16 m) to evaluate the cost-effectiveness of the respective baiting programs in the 2 parks. In the simulation, colonies were eliminable when bait spacing is ≤8 m in Central Taiwan Science Park and ≤12 m in Hsinchu Science Park. The minimized annual cost is estimated at $13.59 million NTD ($453,000 USD) and $14.83 million NTD ($494,000 USD), respectively, while ensuring complete colony elimination. These costs are substantially lower than potential annual losses from termite-induced power outages. These findings provide a practical framework for optimizing bait station deployment in AW termite management programs.