Five-way herbicide-resistant Amaranthus tuberculatus population in North Carolina (USA)
Amaranthus tuberculatus (Amaranthaceae - EPPO A2 List) is an annual dioecious non-native species to the EPPO region with transient and established occurrences known from a number of EPPO countries. The species grows mainly in ruderal sites and along riverbanks, and to a lesser extent in crop fields (EPPO RS 2020/107). The species is native to the Midwestern US where it began infesting agricultural fields in the 20th century within the central portion of its range. Over this time, in North America, A. tuberculatus has evolved resistance to seven herbicide groups and multiple herbicide resistant populations are common. In North Carolina, A. tuberculatus was first reported in 2015 where it infests crop fields. In 2018, seeds were collected from 10 putative multiple herbicide resistant A. tuberculatus plants from a soyabean field in North Carolina. Plants from this population, and a known herbicide susceptible population from Iowa, were tested for resistance to commonly applied post-emergence herbicides. The plants from North Carolina survived the labelled dose rate applications of mazethapyr, atrazine, glyphosate, fomesafen and mesotrion, whereas the plants from Iowa were controlled. 2,4-D, dicamba and glufosinate controlled both the Iowa population and the North Carolina population.
The results suggest a five-way herbicide resistance of A. tuberculatus in North Carolina.
Sources
Jones EAL, Andres RJ, Owen MDK, Dunne JC, Contreras DJ, Cahoon CW, Jennings KM, Leon RG, Everman WJ (2023) Confirmation of a five-way herbicide-resistant Amaranthus tuberculatus population in North Carolina. Weed Research, https://doi.org/10.1111/wre.12590