Conference Agenda

Invasive species are spreading globally, threatening ecosystems, biodiversity, agriculture, and human health. When efforts to prevent the establishment of invasive species fail, and eradication is not possible, containment becomes necessary to slow or stop the spread of established invaders. A major question is, therefore, how to allocate treatment across space and time to contain the population cost effectively. Here, we examine how to optimize the strategies for slowing the spread of the spongy moth (Lymantria dispar) in North America by utilizing gaps with lower densities of host plants. Around these gaps, managers can apply both bio-pesticides and mating disruption methods using synthetic pheromones to disrupt male mate finding. We develop a spatially explicit model of the moth’s population dynamics, and we develop a novel algorithm that finds the spatial distribution of the two methods that optimize the cost-efficiency over landscapes with non-homogeneous distributions of host plants. Our results show that combining pesticide application and mating disruption around host-plant gaps significantly improves cost efficiency: Optimal treatment prescribes mating disruption in low-density regions nearer the moth-free area and pesticides in higher-density regions nearer the invasion front, almost without combining both methods in the same area. Suboptimal strategies that do not optimize the use of host-plant gaps can result in costs higher by tens to hundreds of percent, emphasizing the critical importance of strategic spatial planning for invasive species containment.