Comparing biocontrol and herbicide for managing an invasive non‐native plant species: Efficacy, non‐target effects and secondary invasion

A five-year field trial in Tongariro National Park, New Zealand, revealed that biocontrol using the beetle Lochmaea suturalis was more effective than herbicide (Pasture Kleen®) at reducing heather cover by 97% compared to 87%, while also benefiting native dicot species. Unlike herbicide, which caused significant non-target impacts on native dicots, biocontrol increased their cover and species richness. Both methods led to an eightfold rise in non-native monocots, but secondary invasion was greater with biocontrol due to increased non-native dicot cover. The study suggests that biocontrol may offer broader ecosystem benefits despite higher secondary invasion risks.

Peterson, P. G., Merrett, M. F., Fowler, S. V., Barrett, D. P., & Paynter, Q. (2020). Comparing biocontrol and herbicide for managing an invasive non‐native plant species: Efficacy, non‐target effects and secondary invasion. Journal of Applied Ecology, 57(10), 1876–1884. Portico. https://doi.org/10.1111/1365-2664.13691