Category Archives: Resistance

Making Lemonade Out of Lemons – A Tomato Fungicide Stewardship Tip Amidst Changing Regulations

Cheryl Trueman (Ridgetown Campus, University of Guelph) & Janice LeBoeuf (OMAFRA)

It seems like recently there have been a rash of proposed or pending pesticide regulation changes that affect field growers, and tomato growers are no exception. There are re-evaluations ongoing for a number of products used in tomatoes, including mancozeb, neonicotinoids, and Lannate, as well as Ethrel, but the big one that comes to mind for field tomato growers is the proposed changes to the use of chlorothalonil (Bravo, Echo). The final outcome of this review is not yet known, but it’s likely that significant changes to the chlorothalonil labels are coming.

Chlorothalonil is a go-to fungicide for tomato growers. Data from trials at Ridgetown Campus demonstrate its value. Chlorothalonil is often just as good at controlling early blight, Septoria leaf spot, and anthracnose fruit rot as alternative fungicides, and it also provides protection from late blight, which many targeted fungicides do not. It’s a good value active ingredient for tomato disease management and has a low risk of resistance development. But, if proposed changes go through, the number of chlorothalonil applications you can use will be drastically cut.

So, have you thought about how you are going to adapt? Continue reading Making Lemonade Out of Lemons – A Tomato Fungicide Stewardship Tip Amidst Changing Regulations

Potato Insects – Insecticide Activity Table

Here is a quick reference guide for insecticides registered on potatoes in Ontario. Use it as a guide only, always refer back to the label. Remember to rotate insecticide groups for resistance management.

Potato Insecticide Activity Table Final

Printable Potato Insecticide Activity Table

Continue reading Potato Insects – Insecticide Activity Table

Carrot Weevil Control Update

Carrot weevil remains the most important insect pest to many Ontario carrot growers, and the amount of damage seems to be increasing in recent years. Carrot weevil females overwinter in the soil and plant debris and lay their eggs in cavities in the crown of the carrots. These eggs develop and hatch into larvae and begin to feed on the carrot root. Feeding damage from the carrot weevil larvae causes unmarketable tunneling near the crown of the carrot and can account for significant losses to commercial growers.

Continue reading Carrot Weevil Control Update

Understanding the Strobilurin Fungicides

Rutgers Plant and Pest AdvisoryIn order to understand and use fungicide resistance management strategies effectively, first learn how and why fungicide resistance may develop. This is the third in a series of articles by Dr. Andy Wyenandt, Rutgers Agricultural Research and Extension Center. Originally published in the Rutgers University Co-operative Extension Plant and Pest Advisory. Note that some fungicides mentioned here may not be registered in Canada. Always consult the label for your location before using any crop protectants.

Understanding the Strobilurin Fungicides (FRAC code 11)

The strobilurin, or QoI fungicides (FRAC code 11) are extremely useful in controlling a broad spectrum of common vegetable pathogens. You may know some of strobilurins as azoxystrobin (Quadris), trifloxystrobin (Flint), pyraclostrobin (Cabrio), or Pristine (pyraclostrobin + boscalid, 11 + 7). All strobilurin fungicides inhibit fungal respiration by binding to the cytochrome b complex III at the Q0 site in mitochondrial respiration. Continue reading Understanding the Strobilurin Fungicides

Growers Guide to the DMI or SBI Fungicides

Rutgers Plant and Pest AdvisoryIn order to understand and use fungicide resistance management strategies effectively, first learn how and why fungicide resistance may develop. This is the second in a series of articles by Dr. Andy Wyenandt, Rutgers Agricultural Research and Extension Center. Originally published in the Rutgers University Co-operative Extension Plant and Pest Advisory. Note that some fungicides mentioned here may not be registered in Canada. Always consult the label for your location before using any crop protectants.

Growers Guide to the DMI or SBI Fungicides (FRAC code 3)

The DMI (DeMethylation Inhibitors) or SBI (Sterol Biosynthesis Inhibiting) fungicides belong to FRAC code 3 which include the triazoles and imidazoles. Some of these fungicides are commonly known as Tilt (propiconazole), Rally (myclobutanil), Folicur (tebuconazole), and Procure (triflumizole). Continue reading Growers Guide to the DMI or SBI Fungicides

Growers Guide to Protectant Fungicides

Rutgers Plant and Pest AdvisoryIn order to understand and use fungicide resistance management strategies effectively, first learn how and why fungicide resistance may develop. This is the first in a series of articles by Dr. Andy Wyenandt, Rutgers Agricultural Research and Extension Center. Originally published in the Rutgers University Co-operative Extension Plant and Pest Advisory.

Growers Guide to Protectant Fungicides (FRAC codes M1 – M9)

Protectant (contact) fungicides typically offer broad spectrum control for many different pathogens. Protectant fungicides belong to FRAC groups which have a low chance for fungicide resistance to develop. These include:

  • the inorganics (copper, FRAC code M1) and sulfur (FRAC code M2),
  • the dithiocarbamates (mancozeb, FRAC code M3) and chloronitriles (chlorothalonil, FRAC code M5)

So, why wouldn’t fungi develop resistance to protectant fungicides?

Continue reading Growers Guide to Protectant Fungicides

Get the latest on herbicide resistant weeds in Ontario

Do you want to stay up-to-date on where herbicide resistant weeds have been identified in Ontario? Field Crop News can help with a searchable Master table of all herbicide resistant weed species in Ontario by County and Herbicide Group (confirmed by the University of Guelph). The post also features distribution maps (by county and herbicide group) of resistant weed species.

Here are a couple of examples of search results, the first simply typing in a county.

Herbicide Resistant Weeds - search by county Continue reading Get the latest on herbicide resistant weeds in Ontario