Tomatoes Transplants

Sumagic Plant Growth Regulator label expanded via Minor Use Program to help manage growth of tomato seedlings for transplant

[Note from Janice LeBoeuf, OMAFRA Vegetable Crop Specialist: The field tomato industry is new to using a growth regulator in transplant production. The Sumagic label includes many precautions, especially for inexperienced users. For more information on the use of Sumagic for growth regulation in tomato transplants, please contact Janice LeBoeuf at OMAFRA, Ridgetown at 519-674-1699 or or Kelly Devaere at MGS Horticultural (distributor for Valent) at 519-326-9037 or  They can provide information on using the product and point you to retail outlets of various companies where product is available.]

J. Chaput, OMAFRA, Minor Use Coordinator, Guelph

The Pest Management Regulatory Agency (PMRA) recently announced the approval of an URMULE registration for SUMAGIC TM PLANT GROWTH REGULATOR for regulation of growth on tomato seedlings for transplant. Sumagic was already labeled in Canada for use on a range of greenhouse ornamental species.

The minor use project for tomatoes was sponsored in 2008 by the minor use office of OMAFRA as a result of minor use priorities established by growers, processors and extension personnel. Although the project encountered some challenges, a committed and diligent effort by the registrant, sponsor and PMRA have secured an approved use for Canada tomato producers and processors.

The following is provided as a general outline only. Users should consult the complete label before using Sumagic Plant Growth Regulator.

Application of Sumagic Plant Growth Regulator results in compact transplants with thicker stems that are less likely to be damaged during shipment. Apply a single foliar application of Sumagic at a rate of 5 mL per crop cycle at the 2-leaf stage of tomato transplants using a spray volume of 700 mL per square metre. Apply uniformly as a foliar spray at a volume of 100 mL per tray or 700 mL per square metre.

Do not apply SumagicTM within 100 days of harvest for tomatoes.

Follow all other precautions and directions for use on the Sumagic Plant Growth Regulator label carefully.

We wish to thank John Zandstra, U. of Guelph, Ridgetown Campus, Dr. Jim Dick, Tomato Solutions, John Lang, CanGro Foods Inc. and the Ontario Tomato Research Institute in association with OPVG and OFPA for conducting the Canadian research to support this label expansion. We also wish to thank the personnel of Valent Canada 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 a copy of the new minor use label contact Janice LeBoeuf, OMAFRA, Ridgetown (519) 674-1699, John Zandstra, U. of Guelph, Ridgetown Campus (519) 674-1500 ext. 63627 or visit the Valent Canada website at

Sumagic is a trademark of Sumitomo Chemical Company and is marketed by Valent Canada Inc.

2 comments on “Sumagic Plant Growth Regulator label expanded via Minor Use Program to help manage growth of tomato seedlings for transplant

  1. mike mosesian

    I have 10,000 beef tomato seedlings for tomato production that are just beginning to show the second true leaf and would like to apply Sumagic to keep them compact as they are grown under lights in Anchorage Alaska and stretch a great deal due to the poor light conditions. How many ppm would you suggest I spray with sumagic and at what stage of growth . We will not begin harvesting for more than 100 days.
    Thanks very much

    • Amanda Tracey

      Hi Mike,
      Sumagic is used by a number of tomato seedling growers in Ontario. Most use 1/10 to 1/2 of the label rate at 18-30 days after seeding. Keep in mind that the seedling growers usually operate on a 42 day planning schedule, meaning that the plants are ready to be transplanted 42 days after seeding. if you still have over 100 days to go before transplanting then you may want to plan for more than one application. I would not apply the product within the last 3-4 weeks before planting to make sure the plants are growing out of the affects of Sumagic before they are planted in the field. If you have any other questions you can email me at

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