Why Lontrel shouldn't be used in mustard crops

Non-Peer Reviewe

The effects of hexazinone rates, application timing, and residue management on Canada thistle control and alfalfa seed production

Non-Peer ReviewedHexazinone is an effective weed control tool in alfalfa seed production. However, both researchers and producers have had variable success in Canada thistle control with hexazinone. The objective of this study was to determine the effects of hexazinone rates, application timing and residue management on Canada thistle control and alfalfa seed production. Two field trials were established with ‘Algonquin' alfalfa near Valparaiso, SK and Carrot River, SK in 1998. The Valparaiso trial was located on a fine-textured soil, high in soil organic matter. The Carrot River trial was located on a coarse-textured soil, low in soil organic matter. Three factors (three rates of hexazinone, three residue management treatments and two application dates) were tested in a randomized complete block design. Alfalfa seed yield and Canada thistle: density, dry matter and seed contamination, were determined in 1999. Alfalfa seed yield and Canada thistle control (density, dry matter and seed contamination) increased with increased rates of hexazinone at Carrot River but not at Valparaiso. No significant interactions between hexazinone rates, application timing and residue management for Canada thistle control were observed. However, residue management by application timing interaction was significant for alfalfa seed yield. Alfalfa seed yield was significantly higher following a spring burn at both sites

Triasulfuron and chlorsulfuron persistence under zero and minimum tillage

Non-Peer Reviewe

The effects of preseeding 2,4-D and dicamba + 2,4-D application on subsequent crops

Non-Peer ReviewedThe development of reduced tillage systems and direct seeding systems require the use of herbicides in the fall and prior to seeding to control weeds. A study was initiated in 1988 at Indian Head to examine the effects of 2,4-D amine and 2,4-D amine + dicamba applied in the fall or spring prior to seeding on flax, safflower, mustard, canola, lentil and field pea. Herbicides were applied at the low, high,and double the high rates recommended for use in cereal crops (420, 560, and 1120 g/ha of 2,4-D; and 110 + 420, 140 + 420, and 280 + 840 g/ha of dicamba +2,4-D). Visual crop tolerance ratings, plant populations and yield were assessed in 1988 and 1989. In general, none of the crops tested were adversely affected by faII application of 2,4-D amine alone at up to 1120 g/ha. Spring application of 2,4-D amine alone at 560 and 1120 g/ha caused significant yield reductions in safflower and lentil in 1 out of 2 years but none of the other crops were affected by spring 2,4-D application in either year regardless of the rate. Dicamba + 2,4-D did not cause significant yield reductions in flax, canola or mustard, however, safflower, lentil and pea yields were significantly reduced by spring application of dicamba + 2,4-D regardless of rate and by all but the lowest rate (110 + 420 g/ha) of this mixture applied in the fall

Weed survey and management practices used in alfalfa (Medicago sativa) seed fields in 1997

Non-Peer ReviewedA weed survey in alfalfa seed fields, located primarily in northeast Saskatchewan, was conducted in 1997. Following the weed survey, a farm management questionnaire was used to determine the influence of farm management practices on the surveyed weed community. Results from the weed survey and farm management questionnaire were compared to a similar survey and questionnaire conducted in 1989-90. Wild oats and green foxtail were the most abundant annual grass weeds and their relative abundance did not change significantly. Narrow-leaved hawk’s beard generally decreased in relative abundance while perennial weed species usually increased. Herbicides were the most common weed management practice used in Saskatchewan alfalfa seed fields and their use increased compared to the previous questionnaire. Group 1 herbicide use exceeded the recommended frequency to delay the onset of resistance in wild oats and green foxtail in over half of the fields surveyed. The increase in herbicide use may account for the reduction in relative abundance of some annual broad-leaved weed species between 1989-90 and 1997. The decrease in annual weed competition may have allowed some perennial weeds, which are harder to control with herbicides, to increase in relative abundance

The influence of fall and spring herbicide application on winter wheat

Non-Peer ReviewedThe use of 2,4-D for fall control of winter annuals weeds in winter wheat is recommended in the Canadian prairies but not in other winter wheat production areas. Field research was conducted for two years at several locations using 2,4-0, MCPA, dicamba, dicamba plus 2,4-D, bromoxynil, bromoxynil plus MCPA, chlorsulfuron and clopyralid applied fall and spring. Recommended and double recommended rates were tested to establish the existence of a safety margin. Norstar winter wheat was tolerant to fall applications of all herbicides when applied at recommended rates, however, grain yield was reduced at the double rate with 2,4-D, MCPA, bromoxynil, bromoxynil plus MCPA and clopyralid in some station years. Norstar was tolerant to spring applications of all herbicides except MCPA and clopyralid in several station years. Herbicides tested show promise for use in winter wheat production. Caution is warranted for spring application of MCPA and clopyralid