Pythium diseases of carrot added to the Reason 500SC Fungicide label via the Minor Use Program in Canada

J. Chaput, OMAFRA, Minor Use Coordinator, Guelph

The Pest Management Regulatory Agency (PMRA) recently announced the approval of a minor use label expansion for Reason 500SC Fungicide (fenamidone) for control of damping-off and cavity spot caused by Pythium spp. on carrots in Canada.

Reason 500 SC Fungicide was already labeled in Canada for suppression of downy mildew on bulb vegetables and Brassica vegetables.

The minor use submission for carrots was jointly sponsored by Agriculture & Agri-Food Canada, Pest Management Centre (AAFC-PMC) and U. S. IR-4 program in 2003 as a result of minor use priorities established by producers in Canada and the U.S. This minor use label expansion for Reason 500SC Fungicide helps to address a significant disease problem for carrot producers across North America. The following is provided as an abbreviated, general outline only. Users should consult the complete label before using Reason 500 SC Fungicide.

For damping-off and cavity spot caused by Pythium spp. apply 600 mL Reason per hectare in a spray volume of 300 – 750 L per ha. Make the 1st application within 7 days after planting. A repeat application can be made at a 7 day interval. A maximum of 2 applications per season is permitted, however producers should not apply more than 1 application of Reason 500SC or other Group 11 fungicides without rotating to other fungicide groups. The pre-harvest interval for Reason fungicide on carrots is 14 days.

Follow all other precautions and directions for use on the Reason 500SC label carefully.

Reason 500SC Fungicide should be used in an integrated pest management program and in rotation with other management strategies.

Additionally we wish to acknowledge the personnel of Bayer CropScience Inc. for their support of this registration and the personnel of the Pest Management Regulatory Agency for evaluating and approving this important pest management tool.

For copies of the new supplemental label contact Marion Paibomesai, OMAFRA, Guelph 519-826-4963, Jim Chaput, OMAFRA, Guelph, 519-826-3539, or visit the Bayer CropScience website at

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