Category Archives: Weed Management

66th Annual Muck Vegetable Growers Conference

The 66th Annual Muck Vegetable Growers Conference will be held April 12-13 at the Bradford and District Memorial Community located at 125 Simcoe St., Bradford, ON. The conference is free and registration starts at 8:30. For more details please see:  http://www.uoguelph.ca/muckcrop/muckconference.html

Continue reading 66th Annual Muck Vegetable Growers Conference

Management Strategies to Control Resistant Pigweed in Carrot Production

By: Kristen Obeid, OMAFRA Weed Management Program Lead – Horticulture and Clarence Swanton, University of Guelph

The Problem

Carrot growers in particular are struggling with resistant pigweed in Ontario fields, a problem that was studied extensively in 2011 and 2012. As far back as 1997, resistance to group 5 herbicides (prometryne) was noted. Then in 1998, resistance to group 2 (rimsulfuron) herbicides was noted. Resistance to group 7 (linuron) herbicides appeared in 1999. There are some weed populations with multiple resistance (i.e. resistance to both group 5 and group 7 herbicides or maybe even to three different herbicide groups).

Different pigweed species are showing resistance to herbicides, including:

  • Redroot pigweed (Amaranthus retroflexus, L.)
  • Green pigweed (Amaranthus powellii, S. Watson)
  • Smooth pigweed (Amaranthus hybridus, L.)
  • Common waterhemp (Amaranthus tuberculatus, syn, rudis)

Continue reading Management Strategies to Control Resistant Pigweed in Carrot Production

Prowl H2O Herbicide label expanded via Minor Use Program to control labeled weeds on carrots

J. Chaput, OMAF/MRA, Minor Use Coordinator, Guelph

The Pest Management Regulatory Agency (PMRA) recently announced the approval of an URMULE registration for Prowl H2O Herbicide for control of labeled weeds on carrots in Canada. Prowl H2O Herbicide was already labeled for management of weeds on corn, soybeans, snap beans, adzuki beans, dry bulb and green onions, leeks and ornamentals in Canada. Continue reading Prowl H2O Herbicide label expanded via Minor Use Program to control labeled weeds on carrots

Best Management Practices to Control Herbicide Resistant Weeds in Carrot Production

Click the following link to access the BMP document (pdf file) about managing herbicide resistant weeds in carrot production: 

BEST MANAGEMENT PRACTICES TO CONTROL HERBICIDE RESISTANT WEEDS IN CARROT PRODUCTION

Be sure to check the most up-to-date product labels for directions for use before using any pest control product. The “possible solution” herbicide use patterns are not currently registered for use, but may become available for use over the next few years.

Herbicide resistant weed testing: University of Guelph lab results

Written By: Kristen Callow, OMAF and MRA Weed Management Program Lead – Horticulture

Source: Dr. F. Tardif and Peter Smith, University of Guelph

Adapted from: http://fieldcropnews.com/2013/04/herbicide-resistant-weed-testing-university-of-guelph-lab-results-2013/

Below is a summary of some of the weed samples sent into the University of Guelph by producers and agronomists that suspected resistance to a particular herbicide during the 2012 season. Also included are herbicide options with different modes of action that are effective on each species in horticulture crops. Continue reading Herbicide resistant weed testing: University of Guelph lab results

Management strategies to control resistant pigweed in carrot production

Kristen Callow, Weed Management Lead – Horticulture

The Problem

Carrot growers in particular are struggling with resistant pigweed in Ontario fields, a problem that was studied extensively in 2011 and 2012. As far back as 1997, resistance to group 5 herbicides (prometryne) was noted. Then in 1998, resistance to group 2 (rimsulfuron) herbicides was noted. Resistance to group 7 (linuron) herbicides appeared in 1999. There are some weed populations with multiple resistance (i.e. resistance to both group 5 and group 7 herbicides or maybe even to three different herbicide groups). Continue reading Management strategies to control resistant pigweed in carrot production

Potential management strategies to control resistant pigweed in muck soils

Adapted from The Grower article “Strategies to control resistant pigweed in muck soils” from April 2012

Ontario carrot growers in particular are struggling with resistant pigweed, a problem that was studied extensively in 2011. As far back as 1997, resistance to group 5 herbicides was noted. Then in 1998, resistance to group 2 herbicides was noted. Resistance to group 7 herbicides appeared in 1999. There are some weed populations with multiple resistance (i.e. resistance to both group 5 and group 7 herbicides or maybe even to three different herbicide groups). Weed specialists also suspect resistance to group 14 and group 9 herbicides.

Pigweed in the field

Continue reading Potential management strategies to control resistant pigweed in muck soils