Occurrence and management of PSII-inhibitor-resistant chenopodium album L. In atlantic canadian potato production
McKenzie-Gopsill, A., Graham, G., Laforest, M., Ibarra, S., Hann, S., Wagg, C. (2020). Occurrence and management of PSII-inhibitor-resistant chenopodium album L. In atlantic canadian potato production. Agronomy, [online] 10(9), http://dx.doi.org/10.3390/agronomy10091369
Plain language summary
The Atlantic Canadian provinces of New Brunswick (NB), and Prince Edward Island (PE), are the largest potato producing regions in Canada. Recently, potato producers in the Atlantic region have noticed poor control of common lambsquarters (Chenopodium album L.) after applying their most commonly used herbicide, metribuzin. In this study, researchers wanted to know if the poor control was due to herbicide resistance and then determine other control options for producers. Analyses of tissue samples concluded that 46% of common lambsquarters surveyed were herbicide resistant. Field studies in Fredericton, NB and in Harrington, PE showed that other registered herbicides can control common lambsquarters without affecting potato quality. This study demonstrates that herbicide resistant common lambsquarters are found in Atlantic Canadian potato production systems, but can be controlled with currently registered herbicides.
Potato producers in the Atlantic Canadian provinces of New Brunswick (NB) and Prince Edward Island (PE) rely on the photosystem II-inhibiting herbicide metribuzin for weed management. Recently, potato producers in the region have reported unacceptable common lambsquarters control following an application of metribuzin. Tissue and seed samples were collected from escaped common lambsquarters populations from across the potato producing regions of NB and PE and screened for the Ser264Gly mutation in psbA. Overall, 46% of sampled populations possessed the Ser264Gly mutation across the region. Cross-resistance testing to atrazine, metribuzin and linuron confirmed populations with the Ser264Gly were resistant to triazines and triazinones but remained susceptible to linuron. Dose response analysis determined a moderate level of resistance to metribuzin in common lambsquarters which would not be controlled in producers fields. A field experiment was conducted in Fredericton, NB and Harrington, PE, to determine if currently registered and unregistered products and tank-mixes would control PSII-inhibitor-resistant common lambsquarters in potato. All evaluated products, with the exception of S-metolachlor, provided control equivalent to the weed-free check without compromising potato yield or quality. This study demonstrates that PSII-inhibitor-resistant common lambsquarters are found in Atlantic Canadian potato production systems, but can be controlled with currently registered herbicides and rates with alternative modes of action.