Research Specifications

Mixture of herbicides could help to control wide range of weed floras, postpone resistance to herbicides and reduce herbicides application. A greenhouse study was conducted to assess the effect of individual post-emergence application of 2,4-D plus MCPA in combination with foramsulfuron at two growth stages of redroot pigweed (Amaranthus retroflexus L.). Treatments comprised of untreated control and six rates (67.5, 202.5, 405, 607.5, 810 and 1012.5 g a.i. ha-1) of 2,4-D plus MCPA, which applied alone or in combination with constant rate of 450 g a.i. ha-1 of foramsulfuron. Weeds were sprayed at two- to four- and four- to six-true leaf stages of redroot pigweed. Mixtures were appreciably more effective on redroot pigweed at 4-6 leaf stage compare to 2,4-D plus MCPA, when applied singly. So it is possible to use reduced rates of 2,4-D plus MCPA when combined. However, in 2-4 leaf stage, single application of 2,4-D plus MCPA had better effect compared to combination with foramsulfuron. It seems that at this growth stage of redroot pigweed common and restricted entrance routs of both herbicides have decreased the rate of herbicide absorption and translocation in mixture compared to using 2,4-D plus MCPA.