A field trial conducted by Oregon State University researchers could lead to a special need label for an herbicide that has proven effective in controlling the weed yellow nutsedge in bulb onions.
ONTARIO, Ore. — Oregon State University researchers are trying to provide onion growers in the Treasure Valley of Idaho and Oregon with another tool to control the weed yellow nutsedge in fields where red and white onions are grown.
The Oregon and Idaho agriculture departments last year issued a special local need label that allows the herbicide Outlook to be applied through drip irrigation systems in fields where Spanish yellow bulb onions are grown.
The herbicide was already approved for surface application in onion fields but it wasn’t previously approved for use in drip systems in yellow onion fields.
Now, OSU researchers in Malheur County are conducting a field trial in which Outlook is being applied through a drip system in red and white onions.
If that trial is successful, BASF, which produces Outlook, could apply for a similar special need label for white and red onions, said OSU weed scientist Joel Felix, who is leading the trial.
“We’re satisfied with what we’ve seen so far,” he said of the white and red onion trial.
Felix said a previous yellow onion trial showed that Outlook is much more effective in controlling yellow nutsedge when applied through a drip system compared to surface application.
About 90 percent of the Spanish bulb onions grown in the region are yellows, while the rest are whites and reds. About 60…