Ginseng Crop Update May 11, 2018

Ginseng plants are finally beginning to emerge through the straw. There has been a lot of shade damage in some fields due to the wind storm on May 4. For growers with extensive damage that is not fully repaired yet, a reminder that ginseng is not very sensitive to sunlight until the tops begin to unfold and point to the sky. There is still time to fix the shades without causing much damage to the plants.

In older gardens, shade that collapsed on the bed may have damaged some of the plants that had begun to emerge. If this is the case, the biggest risk is botrytis leaf and stem blight if weather becomes warm and humid. Ensure fungicides are applied to protect against this disease.

Pesticide Re-Evaluations

The Pest Management Regulatory Agency (PMRA) has issued its final decision on the re-evaluations of chlorothalonil (Bravo/Echo) and captan (Maestro/Captan) fungicides. The decisions will be implemented within the next 2 years. Once implementation occurs, ginseng growers will only be allowed 3 applications per year of chlorothalonil products instead of the current 6 applications, with one of those three applications only being allowed as a final protective spray in the fall.  This is an improvement over the 1 application per year that was originally proposed by PMRA. The change was made after PMRA factored in better information provided by the Ontario Ginseng Growers Association on ginseng production practices and the potential for worker exposure. The number of applications of captan on ginseng will not be changed, and this is consistent with PMRA’s original proposed decision. Additional worker and environmental safety precautions will be included on the new label for both products. Restricted Entry Intervals for both products are being reduced.

The decision on chlorothalonil products will have a significant impact on ginseng production. Growers will have to adjust by replacing these applications with one of the remaining products registered for foliar disease management on ginseng. Growers will need to start experimenting now with different products to see what will work best as a replacement. Note that the maximum number of applications per year of any product applies to the active ingredient and not the trade name, so you will only be allowed to apply a total of 3 applications of all chlorothalonil products per year. For example, if you apply 2 applications of Echo and then 1 application of Bravo, you will have reached the maximum applications for both.

About Sean Westerveld

Ginseng and Medicinal Herbs Specialist, OMAFRA
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