The health of forests worldwide is threatened by insect pests and diseases. For example, outbreaks of defoliating insects reduce production efficiency, and the continued introduction of invasive pests is stretching the available capacity and resources to manage these threats. Research in various disciplines is needed to unlock new approaches to manage forest pests, including a shift in focus from chemical to biological control. In addition, many of the current threats require cross-boundary and multi-disciplinary approaches.  This joint meeting will exchange information on the theory and practice to address defoliating insects and invasive species of forests, including biological control and other approaches. The meeting will include researchers from different disciplines and countries and provide an overview of the challenges to forest health, and research driven responses to these challenges.