CANOLA QUIZ – Weed management

Eight questions this week – four on agronomy as it relates to weed management and four on weed identification.

1. Many studies have shown the yield benefits of early weed control to remove weeds before they tie up nutrients and moisture and out-compete for sunlight. AAFC weed scientists Neil Harker and John O’Donovan estimate that the yield effect of one weed emerging a week before the crop is equivalent to that of ___ weeds emerging three weeks after the crop. (Fill in the blank.)
2. Hot weather is generally not ideal for herbicide efficacy. Liberty, which works better than most herbicides in hot, sunny conditions, can cause “bronzing” of canola leaves when temperatures exceed ______. (Fill in the blank.)

3. Herbicide efficacy can depend on water quality. Hard water high in calcium and magnesium will reduce the performance of glyphosate. What is considered the maximum water hardness (in calcium carbonate equivalents) for glyphosate?
4. Group 1 clethodim can be tank mixed with Group 10 glufosinate to enhance grassy weed control in Liberty Link canola, but what if the field has a lot of Group-1 resistant wild oats? Growers can improve glufosinate (Liberty) activity on grassy weeds by using 10 gallons, or more, of water per acre and _______________.
5. Weed ID – head to heat, part 1: What are these weeds?

6. Weed ID – head to heat, part 2: What are these weeds?

7. Weed ID – head to heat, part 3: What are these weeds?

8. Weed ID – head to heat, part 4: What are these weeds?