Global land-use change and the importance of zoophytophagous bugs in biological control: Coppicing willows as a timely example

Perennial plants, such as willows, miscanthus, and hybrid poplars, are promising bioenergy crops while lowering atmospheric CO2. Increases in the acreage of perennial bioenergy crops will pose new challenges and opportunities for biological control. In this review, we suggest that zoophytophagous bugs could be expected to become increasingly important in biological control of arthropod pests in perennial bioenergy crops. The main reasons are: (1) perennial bioenergy crops provide suitable habitats for arboreal natural enemies like zoophytophagous bugs; (2) zoophytophagous bugs often increase in response to low disturbance frequencies; and (3) plant-feeding by zoophytophagous bugs will not likely affect plant biomass production in perennial crops. We review aspects of the biology of zoophytophagous bugs expected to be important in biological control of pests in perennial systems. We also present a predator–prey model investigating how alternative harvest methods affect biological control of herbivorous pests by zoophytophagous bugs in willow biomass plantations. Although there is good evidence that zoophytophagous bugs can provide pest control, more research is needed about factors affecting the dispersal and population dynamics of zoophytophagous bugs in agricultural landscapes.

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► Perennial bioenergy crops may increase in the future.
► Zoophytophagous bugs can be expected to become important in biological pest control.
► Bioenergy crops provide suitable habitats for arboreal natural enemies.
► Alternative harvesting methods may promote biological control.