Selectivity of the Premixtures Flufenacet, Diflufenican and Flufenacet, Diflufenican, Metribuzin on Bread Wheat (Triticum aestivum L.) and Barley (Hordeum vulgare L.) and Efficacy on ALS/ACCase-Resistant Populations of Lolium rigidum Gaudin

Abstract

The premixtures flufenacet plus diflufenican and flufenacet plus diflufenican plus metribuzin are two herbicides recently registered in Greece for weed control in bread wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) with application early post-emergence to the crop (1st–3rd leaf growth stage). To evaluate the selectivity of these new herbicides, pot experiments were conducted by applying flufenacet plus diflufenican at 240 + 120 g ai ha−1 and flufenacet plus diflufenican plus metribuzin at 119.7 + 119.7 + 44.8 g ai ha−1 to bread wheat and barley, at 1st (BBCH-11), 2nd (BBCH-12) and 3rd (BBCH-13) leaf growth stage. The efficacy of the herbicides at the above-mentioned rates in pre-emergence application was also tested on three ALS/ACCase herbicide-resistant populations of Lolium rigidum Gaudin in comparison with the pre-emergence herbicides prosulfocarb and chlorotoluron plus diflufenican at 3200 g ai ha−1 and 1380 + 92 g ai ha−1, respectively. The results revealed decreased selectivity of both premixtures when applied at BBCH-11 for both winter cereals, with flufenacet plus diflufenican being less selective compared to flufenacet plus diflufenican plus metribuzin. Both herbicides highly controlled the three herbicide-resistant L. rigidum populations. The results indicated that both premixtures are effective chemical options for the management of herbicide resistant L. rigidum. To ensure crop safety and optimize efficacy, application at BBCH-12 is recommended.