Replace of the EPOST glyphosate with pre herbicides and application of different LPOST glyphosate rates for weed control in established vineyard
<p>Two-year field trials were conducted at two winegrowing districts (Kavadarci and Skopje in 2016 and 2017) to evaluate wheather oxyfluorfen, pendimethalin and flazasulfuron can replace early post-emergence (EPOST) application of glyphosate in established vineyard until its application in early summer period. The weed vegetation in vineyards in both years was consisted mainly of <em>Chenopodium album </em>L.<em>, Setaria viridis </em>(L). Beauv.,<em> Papaver rhoeas </em>L.<em>, Xanthium strumarium </em>L.<em>, Lolium multiflorum</em> Lam., <em>Sorghum halepense </em>(L.) Pers.<em> </em>and<em> Cynodon dactylon</em> (L.) Pers. Pendimethalin, oxyfluorfen and flazasulfuron efficiently reduced predominant annual weeds and <em>S. halepense</em> seedlings in 2017, but not in 2016. PRE herbicides, regardless year, had no significant effect on <em>C. dactylon</em>. Opposite, the efficacy of EPOST applied glyphosate was significantly lower in 2017 compared to 2016. LPOST glyphosate applied at 2.0 l ha<sup>-1</sup> provided at least 94 % control of dominant annual broadleaf and grass weeds. LPOST application of glyphosate at 2.0 l ha<sup>-1</sup> and glyphosate at 2.0 and 4.0 l ha<sup>-1</sup> resulted in unsatisfactory weed control of predominant perennial <em>S. halepense, </em>and<em> C. dactylon</em>, respectively. LPOST glyphosate applied at 4.0 l ha<sup>-1</sup> provided control of <em>S. halepense</em> by 84 % or more. LPOST glyphosate applied at 8.0 l ha<sup>-1</sup> reduced the amount of <em>S. halepense </em>and<em> C. dactylon</em> at least 97 %. Grapevine yield of both varieties was not lower in all herbicide treatments in 2016 compared with 2017. However, yield in the PRE herbicide treatments fb 2.0 and 4.0 l ha<sup>-1</sup> glyphosate was collectively 15-19 % and 17-19 % lower compare to PRE herbicide treatments fb 8.0 l ha<sup>-1</sup> glyphosate and standard two applications of glyphosate, respectively for both years and districts. No impacts to grapevine growth were observed from PRE herbicide treatments at either district</p>