Canada’s horticultural industry was set on its heels earlier this winter when the Pest Management Regulatory Agency (PMRA) announced the re-evaluation of a commonly used active ingredient, chlorothalonil. This is an important active ingredient in fungicides such as Bravo and Echo, widely used by potato growers and many other commodity groups to prevent foliar diseases such as late blight.

The industry’s protests about the lack of forewarning have resulted in an extension on comments until June 9.  

The extension was announced at the Canadian Horticultural Council annual general meeting by Margherita Conti, director-general, value assessment, re-evaluation management directorate, PMRA. The agency will host a webinar on April 8 to outline how officials came to their conclusions. 

If the re-evaluation was a surprise to growers, it was no less so for the three registrants of the active ingredient:  Syngenta (Bravo), Sipcam (Echo) and Adama (Equus). The latter registrant bought the rights to the data to get a generic product registration as recently as December 2015. The re-evaluation notice means that the fungicide use would be reduced from 12 times per season to one in potatoes and eight times per season to one in tomatoes. Fungicide use would be totally eliminated in onions, crucifer crops, sweet corn, strawberries, cranberries and blueberries.

Re-evaluation also includes uses beyond horticulture. For growers of lentils, the loss of this fungicide would impact one million acres on the prairies.

PMRA’s posting of chlorothalonil  -- and other actives -- on a re-evaluation list is driven in part by the Commissioner of the Environment and Sustainable Development Report on Pesticide Safety, published on January 26, 2016. The crux of the issue is worker safety.

“The Canadian horticultural industry takes worker safety seriously,” says Craig Hunter, pesticide expert with the Ontario Fruit and Vegetable Growers’ Association (OFVGA).  “However, the regulators are basing their decision in part on calculated dermal toxicity values rather than the actual 21-day study they had accepted as late as 2011. They did not ask the registrants for extra data such as 90-and 180-day dermal tox studies that could have provided ‘real’ data points.”

Horticulture’s concerns are broader than chlorothalonil since other active ingredients are also under review.  

“If we lost even half of this list of active ingredients, it would knock out the foundation of horticulture in Canada,” says Hunter.

The ongoing discussion with PMRA is about use patterns: that is, how growers use the product in the field. Concerns about worker safety can be addressed when it is understood how and when products are used in day-to-day practical settings and what worker activities actually occur in treated fields in the season.

Margherita Conti reported to the CHC gathering that PMRA will be developing a policy on the phase-out of affected pesticides by June 2016. Other policies are under review for consulting stakeholders. She also announced a pilot approach for increased early stakeholder engagement to provide input on the use pattern for use in risk assessment.

In a question-and-answer period following Conti’s presentation, several attendees commented.  

“My family farms within a mile of the U.S. border,” said Keith Kuhl, CHC president. “U.S. potato growers can ship into the Canadian marketplace using products containing chlorothalonil, but the prospect is that we won’t be able to use these products. We have to continue to work on these issues.  Otherwise, we will continue to give our trading partners advantages in the marketplace.”  

Conti replied that PMRA will evaluate the Canadian use pattern.

Murray Porteous, a fruit and vegetable grower from Simcoe, Ontario, explains that Bravo is used in asparagus after the harvest to keep the fern healthy and to help produce tender shoots the following spring. 

“Although this product is just one of a few options, removing one product is like removing one in a house of cards,” he says. “Your tender plants can become infected with disease very quickly resulting in less quantity and poorer quality for the consumer.”
    
At the CHC meeting, Porteous addressed Conti’s presentation. 

“It frustrates me when science is viewed differently in the U.S. and Canada,” Porteous said. “It undermines public confidence. It frustrates me as a farmer who can’t compete. All of this drives up costs to the producer.”

Conti replied:  “Bear in mind, as we try to harmonize approaches to the science, we are constrained by the Pest Control Products Act. We have Canadian policies that the U.S. may or may not have. That being said, when we re-evaluate, we look at other jurisdictions. Through re-evaluations, you may be losing product use. PMRA does look at alternatives and how useful those alternatives might be for specific crops or pests.  Let’s take the wireworm example in potatoes. PMRA worked with grower groups and provinces to come up with solutions. I believe that in the end, we worked collaboratively with stakeholders.”

In another exchange, Jonathan Atkins, representing TKI from the U.S. said, “This re-evaluation list seems like a dramatic change. This is actually a cancellation list, not a re-evaluation list.”

Margherita Conti’s presentation was followed by Tracy Shinners-Carnelley, vice-chair of the CHC Crop Protection Advisory Committee. A national response will be developed based on surveys and input from provincial members, grower associations, CropLife Canada, registrants and all interested stakeholders.

For each commodity group, there will be an overview of: production (statistics, distribution); actual grower use; extent of use (application rates/frequency, re-entry, aerial application); use with other tank-mix products; and alternative chemical controls.

“These decisions have cumulative effects,” said Shinners-Carnelley. “There is a cumulative impact of PMRA decisions on pest control in fruit and vegetable crops, when there are few or no options remaining to control pests. Resistance management is increasingly becoming more prominent. Our competitiveness is decreasing with increasing divergence from the U.S.” 

She counseled that pest management should be a systems approach, retaining multiple tools with rational label uses.

“Let’s consider product re-evaluations as part of a pest management system and not in isolation.”