Get reliable science

Several herbicides were evaluated for control of honey mesquite (Prosopis glandulosa Torr.) when applied with a tractor-mounted carpeted roller. Experiments were placed in stands with relatively high honey mesquite densities (2,850 to 4,930 plants/ha). An ester of 2,4,5-T was ineffective at concentrations ranging from 3 to 240 g/L when applied monthly from April through September. Equal-ratio mixtures of 2,4,5-T and picloram provided up to 80% mortality (root-kill) when applied at a total concentration of 24 g/L in June, but did not control honey mesquite if applied in September. Mortality obtained with picloram applied alone in June as a 12 g/L solution varied with year and location from 42 to 61%. Picloram provided 61 to 91% mortality at a concentration of 60 g/L when applied in June, and up to 99% mortality when applied as a 120 g/L solution. Picloram was highly effective when applied in July and August in a year of favorable growing conditions, providing 94 and 96% mortality as 60 g/L solutions, respectively. Mortality was reduced to a maximum of 79% when picloram was applied from April through September in a drought year. Clopyralid and a 1:1 mixture of picloram and clopyralid were usually equal or superior to picloram in effectiveness. This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries. The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information. Migrated from OJS platform August 2020