When’s the best time of day to spray herbicides? Morning, midday, or night time?
College of Guelph weed scientist Dr. Peter Sikkema says that each herbicide has a time-of-day impact however typically talking growers get the best weed management at 3:00 pm in the afternoon. That’s Sikkema’s conclusion primarily based on time-of-day efficacy trials he carried out utilizing 13 energetic elements.
Sikkema’s workforce of analysis assistants and graduate college students put in some lengthy days to take a look at every energetic ingredient, spraying them in three-hour intervals starting at 6:00 am by way of to midnight. He experiences that the efficacy of each herbicide tends to observe an inverted U-shaped curve with poorest management coming at 6:00 am and midnight.
The diploma of the curve varies enormously for various chemistry. The curve is virtually flat for glyphosate, he notes. “Farmers know they can spray glyphosate anytime and they are going to get good weed control.”
A product like Liberty (glufosinate) has a a lot steeper curve to its time-of-day impact. On this episode of RealAgriculture Corn College, Sikkema notes that spraying Liberty at midday in contrast to midnight can enhance yield by up to 50 bu/ac.
Whereas mid-day spraying does provide the best management, it does current some dangers. Analysis additionally reveals that weed management and crop damage have a tendency to observe the similar line. “When you get the best weed control at 3:00 pm, you also have the greatest crop injury,” Sikkema provides.