Determination of optimal doses of glyphosate for controlling weeds at several stages in southwestern Buenos Aires province (Argentina)

Abstract

Efficient weed management is essential for avoiding competition for water, light, and nutrient resources in semiarid zones. Chemical weed control with glyphosate was evaluated on perennial wall-rocket (Diplotaxis tenuifolia), artichoke thistle (Cynara cardunculus), slender wild oat (Avena barbata), and perennial ryegrass (Lolium perenne). Plants at early, middle and advanced vegetative stages were used in this study. Glyphosate potassium salt was applied at rates of 0.0675 (1/16x), 0.135 (1/8x), 0.27 (1/4x), 0.54 (1/2x), 1.08 (x) and 2.16 (2x) kg acid equivalent (ae) ⋅ ha -1 . Glyphosate combined with 2,4-D amine salt was evaluated at rates of 1.08 kg ae ⋅ ha -1 and 0.53 kg active ingredient (ai) ⋅ ha -1 , respectively. The volume of the spray was 100 l ⋅ ha -1 with 86 droplets ⋅ cm -2 and a Volume Median Diameter (VMD) of 421.19 µm. In general, all the tested weeds were controlled with a quarter of the label rate. Three sizes of tested plants were controlled in a similar way at the same glyphosate dose rate. Moreover, the addition of 2,4-D to glyphosate did not produce an increase in the control of broadleaf weeds. The results showed that glyphosate was effective in controlling the tested weed species, including low application rates for all the growth stages in the southwestern Buenos Aires province.

Journal of Plant Protection Research

“…The herbicide glyphosate is very important in the management of weeds, especially in soybean and maize crops (Bentivegna et al 2017). However, the association and rotation of herbicides are important tools in the management of weeds which are difficult to control (Riar et al 2013).…”