Originally Posted by turfmd101
Ok I will try to clarify. The atrazine label says not to spray over certain temps. They say its too hot and it will burn. I understand they are covering their liabilities. I have sprayed atrazine in 102 temps. No damage to follow because I took into consideration the turfgrass conditions. Very healthy and strong. No problem for atrazine. Now it wasn't off label at that temp just off suggestion. I would not spray within 25 feet of the mean water line. That's off label. If the label says I can't, I don't. If it says I shouldn't because of risk. I'll make that call on my experience. Not the label. I still have no trouble killing dollarweed new or older with atrazine.
Posted via Mobile Device
Well they are correct; it has nothing to do with liabilities as opposed to a scientific certainty borne out of experience in product trials.
To recommend applying Atrazine or virtually any broad leaf herbicide @ temps approaching 102, and assuming the turf is "healthy enough" to tolerate it (specially without having been out to the site) is wildly speculative and irresponsible!
Even applying Celcius or Metsulfuron (noted for minimal stress to St. Augustine turf at higher temperatures) at temperatures approaching 100 is at the very least unwise if not just plain stupid.
If my PCO even considered recommending doing that, he'd be replaced.