Managing herbicide resistant weeds in pulses with alternative modes of action
- Agriculture and Agri-Food Canada
- Herbicide Resistance
- Pulse Science Cluster
- Weed Management
Lead Investigator(s) Institution
Agriculture and Agri-Food Canada
To generate additional data to support the registration of herbicides (flumioxazin, fluthiacet-methyl, pyroxasulfone, propyzamide). To develop a pre-and post-emergence herbicide strategy for controlling cleavers in field pea in the black soil zone. To identify tank-mix options to control glyphosate-resistant kochia pre-seed prior to seeding pulse crops.
Experiments conducted at the Scott Research Farm (dark brown soil zone) from 2014-2017 evaluated herbicides and herbicide combinations with alternative modes of action (eg. Group 3, 6, 14, and 15) in lentil and field pea. Pyroxasulfone is a Group 15 soil applied herbicide that requires moisture for activation. Application timing (fall vs spring) may reduce risk of failure as winter snowmelt may activate the herbicide. In 2014 & 2015, fall application provided higher levels of wild oat control than spring application. In 2016, spring soil moisture was insufficient to activate the fall application while late May rains activated the spring-applied pyroxasulfone resulting in higher levels of control of the predominant weed, wild mustard, vs. the fall application. Application timing did not affect wild mustard control in 2017. Overall, pyroxasulfone provided suppression to control of wild mustard, which was rate and timing dependent. Fluthiacet-methyl, a Group 14 post-emergence herbicide, has been shown to be quite effective in controlling Group 2 resistant kochia, and may be a potential tank-mix partner with other broadleaf herbicides. Visual tolerance of lentil to fluthiacet-methyl is marginal, therefore research was focussed on reducing injury. In 2015, injury to Maxim lentil from fluthiacet-methyl application was reduced by applying at the 3-node stage of lentil, compared to the 6 or 9 node stage. In 2016, application timing did not have an effect on crop injury. In both years of the study, initial injury from fluthiacet-methyl was transient and did not result in reduced yields. Flumioxazin (Group 14 soil applied herbicide) applied in late fall at rates of 70 grams of active ingredient per hectare (g ai ha-1) reduced kochia biomass by approximately 78% with rates > 107 grams of active ingredient per hectare (g ai ha-1) resulting in greater than 95% reduction. Ethafluralin/propyzamide in combination generally resulted in better control of wild oat than either product applied alone; however, lentil tolerance was marginal. Pre-emergence applications of sulfentrazone or clomazone followed by post-emergence applications of imazamox + bentazon were effective in suppressing or controlling cleavers in field peas in the black soil zone. Pre-seed burndown studies for controlling Group 9 resistant kochia provided the following results: - carfentrazone applied at 18 grams of active ingredient per hectare (g ai ha-1) provided higher levels of kochia control compared to a rate of 9 grams of active ingredient per hectare (g ai ha-1): however, surfactant (Agral 90 or Merge) had minimal affect; - mixing bromoxynil with carfentrazone resulted in higher kochia control compared to bromoxynil alone; - combining carfentrazone with sulfentrazone resulted in >90% control of kochia 30-45 days after treatment; - pre-seed applications of flumioxazin and pyraflufen + MCPA resulted in >85% control of kochia 30 days after treatment.
Duration/Timeline of Project (Year to Year)
2013 - 2018
Agriculture and Agri-Food Canada
Total Project Cost