Evaluating the Potential of <em>Cuscuta japonica </em>as Biological Control Agent for <em>Derris trifoliata </em>Management in Mangrove Forests

Climbing vines induce increasing threats to forest growth under favourable environmental changes recently. In mangrove forests, the native vine Derris trifoliata became invasive and is now one of the main threats. Yet current management relies on manual removal with low efficiency. Exploring alternative cost-effective method is required. To assess the potential of a proposed biological control method, this study performed a pot-plant experiment using Cuscuta japonica to infect D. trifoliata and three common mangrove species in Beihai, China. Results showed that D. trifoliata had higher infection rate and high host mortality than mangrove. It also had significantly decreased moisture, nitrogen, phosphorous, potassium and increased soluble sugar and protein, whereas only moisture and one or two minerals of Excoecaria agallocha and Aegiceras corniculatum were influenced. Only Kandelia obovata had neither effective haustoria nor nutrients impact from the infection. This study indicated that C. japonica can do more damages to D. trifoliata than to mangrove species and has the potential to be used as biological control agent to the threatened mangrove forests of A. corniculatum and K. obovata with monitor and control. Further tests in the field are required to bring this method into practice.