The Southeast Farm Press published an interesting article back in March 2014 which was reposted in their most recent newsletter today on the impacts of time of day on herbicide effectiveness. According to field research done by UGA and other scientists on cotton, spraying herbicide early in the morning around sunrise is much less effective than spraying it later in the day.
The lack of effectiveness was linked to light winds, which are most frequent around sunrise. Light winds are not effective at moving the pesticide around the field. Later in the day, the winds pick up and distribute the herbicide much more effectively throughout the crop, making it cover the field more completely. Since farmers are out spraying their crops again this time of year, it is a timely article worth reposting.
