QUIZ – Pre-seed burnoff

Jay Whetter

Four questions on the theme of pre-seed weed control. While it may be too early to spray this week, growers and agronomists could test well water and dugout water used for spraying.

1. Page 56 of the Saskatchewan and Manitoba Guide to Crop Protection 2026 lists pre-seed burnoff options. Four pre-seed herbicide options for fields planned for canola include the group-6 active ingredient bromoxynil. One herbicide, Tough EC, also includes a group-6 active ingredient, but it’s not bromoxynil. What is it?
2. It helps to read label details. Not all products perform the same, even if they're in the same herbicide group. To build on question 1, the label details for bromoxynil say to apply on kochia before kochia plants are two inches high. However, Tough EC label (the product with the other group-6 active) says "Unless otherwise noted below, apply to young and actively growing weeds that are ________ in height or width." (Fill in the blank)
3. The Canola Watch Fundamentals article Pre-seed burnoff: Tips for best results says to wait for warm, sunny daytime conditions, adding: This is especially helpful when targeting perennials or winter annuals that may be a little larger. Ideally, you want a day or two of warm sunny days and night time lows of ________ before spraying. (Fill in the blank.)
4. Sprayer water with a lot of cations can immobilize glyphosate. The cation calcium, for example, has a plus-two charge and glyphosate has a negative-one charge. Thus, every calcium cation in hard water can bond with two glyphosate molecules. This creates a useless new molecule called calcium glyphosate. What water hardness level is considered the general threshold for action to correct that hardness?

 

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