Biological Control of Sphaeroma Terebrans

Abstract

Development of eco-friendly and environmentally safe ways to control the wood-boring mangrove isopod Sphaeroma terebrans. Feeding experiments were used to identify crab species that act as predators of Sphaeroma. Four types of crabs commonly found in mangroves were selected, including Perisesarma bidens, Metaplax longipes, Helicana japonica, and Uca arcuata. The survival rate of Sphaeroma subjected to various temperatures (5?, 10?, 40?, and 45?) was determined. The efficiency of high temperatures and low temperatures, generated by a steam cleaner and dry-ice fire extinguisher, respectively, to kill the Sphaeroma outdoors was determined. In the forest, pure salt, saturated salt solution water, and a mixture of salt and mud were used to kill the Sphaeroma. The method of dehydrating and killing of the Sphaeroma was used to eliminate the Sphaeroma. The order of feeding efficiency on Sphaeroma was: Perisesarma bidens > Metaplax longipes > Helicana japonica. Uca arcuata could not feed on Sphaeroma. Furthermore, 100% of Sphaeroma died following high-temperature treatment (6 min at 45?) while 80% died following low-temperature treatment (10 min at 5?). Using the steam cleaner or dry-ice fire extinguisher provided effective, but impractical, methods of killing Sphaeroma. The mortality rate of Sphaeroma was 96% after 2h of outdoor pure salt treatment, 92% after 2h of saturated saline treatment, and 72% after 2h of salt and mud mixture. Among the four crab species tested, the best feeding results on Sphaeroma were obtained with Perisesarma bidens, indicating it can be used in biological control as a natural enemy of Sphaeroma. Sphaeroma terebrans was not able to withstand temperatures of 5? or below, or 45 ^oC or higher. The use of a salt solution is an effective, feasible, and environmentally friendly method to control Sphaeroma terebrans, which can be popularized in practice.