Ecological engineering to manage populations of invasive pests

Exotic invaders are some of the most serious insect pests in agricultural landscapes around the globe. These species cost human societies billions of dollars annually in lost yield and control expenses. For many of these invasive pests, chemical pesticides are still the dominant form of control, and contribute to additional costs in the form of degraded environmental and human health. Increasingly, landscape and habitat structure is recognized as having a major influence on both insect pests and their natural enemies. Manipulating these factors to enhance conservation biological control is a form of ecological engineering that has great promise and a rapidly developing set of theory and methodologies. One example where this approach has been successful is in the control of the light-brown apple moth (Epiphyas postvittana) in New Zealand. Enhancing the abundance, fitness and efficacy of parasitoid natural enemies of this pest in vines, through the provision of nectar from buckwheat (Fagopyrum esculentum), has reduced pest numbers below the economic threshold and led to widespread adoption by winegrowers. Current work is analysing the “sugar signatures” of buckwheat and a range of New Zealand endemic plants in an attempt to identify species of the latter with conservation biological control potential similar to or greater than that of buckwheat. We also detail related work on North American native plants for habitat management and the suite of ecosystem services, in addition to biological control, that can accrue by incorporation of native plants into agricultural landscapes.