Iinfluence of lentil seeding rate on dose response of wild mustard to fluthiacet-methyl

Non-Peer Reviewed

In recent years concern over the development of herbicide resistant weeds has lead to interest in integrated weed management systems that seek to relieve selection pressure for herbicide resistance by utilizing mechanical and cultural controls in addition to herbicides. The cultural practice of increasing crop seeding rate has been identified as having potential to provide non-chemical weed control and enhance the effects of herbicide application. The objective of this study was to examine the interaction between increasing seeding rate and the dose response relationship of weeds to herbicide application. Lentil was chosen to represent the crop, with wild mustard as the weed, and fluthiacet-methyl the herbicide. The experiment was a factorial design with four levels of seeding rate (70, 140, 280, and 560 plants m-2) and seven levels of herbicide application rate (0, 0.94, 1.87, 3.75, 7.5, 15, and 30 g ai ha-1). The study was conducted at two locations near Saskatoon, Sk. in 2012. Results of the experiment show that increasing lentil seeding rate decreased the total mustard biomass when herbicides were not applied or were applied at low rates. In addition increasing lentil seeding rate lowered the herbicide dose required to result in a 50% reduction in mustard biomass. Doubling seeding rate from the recommended rate to 280 plants m-2 reduced reliance on herbicide application to maintain lentil yield. These results suggest that the practice of increasing seeding rate can work with herbicide application to reliably and effectively control weeds, even in situations where herbicides alone may not achieve good control.