With challenging spray conditions, including crop and weeds weakened by frost and cool weather, growers need to consider steps to improve herbicide performance and limit crop damage. These steps will be different for each herbicide, so pay attention to product label instructions and restrictions.
If you missed Tom Wolf’s webinar last week on “Spraying tips for 2011,” click here to view an archived version.
Here are key points from the webinar:
Timely spray is more important than nozzle choice. AAFC research showed that spraying 7 days after crop emergence generated higher yields than spraying 17 days after emergence, no matter the droplet size. Using a low drift nozzle early was better than waiting longer for a relatively calm day to use a finer spray.
Glyphosate is suited to low drift (coarse droplets) sprays, but remember that at the low water volumes that favour glyphosate, coarse sprays may not provide enough droplets per square inch. A combination of coarse spray and low (but not ultra low) water volume is best to make sure you get droplets on even the smallest weeds.
Liberty needs at least 10 gallons per acre. With coarse droplets, higher water volumes are needed to maintain efficacy. Click here for more information.
Keep your boom low to reduce drift, but make sure to use a nozzle with a fan angle to provide 100% overlap at low heights. Spray from one nozzle should reach to the middle of the spray pattern of the adjacent nozzle.
Calm early mornings can actually increase spray drift damage. The spray can hang in the air, making it impossible to predict when and where it will settle. This dense cloud can do a lot of damage to a neighbor’s crop or yardsite. Bright sunny days with some wind are ideal times to spray to minimize drift damage. If those days are hard to come by, click here for tips for spraying in wet conditions.