Agriculture, Fisheries and Aquaculture - Effect of Various Herbicides on Barspectra Rye-grass Grown for Seed Production

Abstract: A trial to evaluate the effect of various herbicides on "Barspectra" rye-grass grown for seed production was established at Killoween, Carleton County. Visual ratings on crop injury, crop vigour, hempnettle and lambs quarters control were collected. In addition, ryegrass seed head counts per m2, thousand kernel weights, % germination, and yields were collected. Results indicated that crop injury reported at the first rating (9 days after application) was between 9 and 25% for all treatments except Aatrex (atrazine), which had injury levels of 96%. Initial injury was short-lived however, as all treatments, except Aatrex, recovered as the season progressed. Analysis of final crop injury ratings, crop vigour, and rye-grass seed head counts m2, indicated that the same four treatments provided the best results. These included two MCPA treatments (1.25 and 1.75 L/ha); Refine Extra + Agral 90; and Buctril M. Percent germination from all the treatments ranged from 77% to 89% and were not significantly different from each other. Analysis of yield data indicated that the highest yielding treatment was the untreated weedy control. This was surprising and unexpected as these plots had the greatest weed pressure, lowest vigour, next to lowest seed head counts, and had thousand kernel weights that were not significantly higher than the other treatments. Although yields from the weedy control plots were the highest, they were not significantly higher than the remaining treatments (with the exception of Aatrex). This indicated that great variability existed throughout the plot area. Further research is required to determine if herbicides reduce seed yields or if the results were a function of the variability in soil type, planting, and drainage observed at the trial site. All treatments evaluated provided excellent lamb's quarters control. The only treatments that did not provide acceptable hempnettle control by the final rating were 2,4-D amine, and Basagran+Assist.

¹Potato & Horticulture Branch, NBDARD, Fredericton, NB E3B 5H1
²Livestock & Livestock Feed, NBDARD, Fredericton, NB E3B 5H1
³Killoween Farms Limited, Upper Kent, NB E0J 1Y0