Weed control research in 2019 included a focus on the herbicide Loyant.
Eric Webster, LSU AgCenter weed scientist, said he tested treating granular fertilizer with Loyant herbicide.
He said he wants to do more testing in 2020 to determine if Loyant’s effectiveness is compromised when added to a fertilizer.
“It doesn’t appear that it does, but we want to make sure,” Webster said.
He said the combination will work well if weeds are small.
“On 1- to 2-inch weeds, it seems to be doing a pretty good job,” Webster said. “If it’s 2 or 3 inches out of the water, you’ll have trouble controlling it.”
He said the testing in 2019 involved applying the herbicide-treated fertilizer in flooded rice but testing in 2020 will include testing on dry soil.
He said he also tested Loyant mixed with benzobicyclon and Gambit to find out if the combined chemicals lose their weed-control characteristics.
Webster said he will be testing a reduction of the rate of the Provisia herbicide to three 10-ounce applications to stay within the 31-ounce restriction for a crop. Current recommendations call for two applications of 13 to 15 ounces.
He said the Provisia technology continues to help farmers control problem fields.
“I think the PVL02 will be a better option for us,” Webster said.
Webster said the challenges of the 2019 growing season included an unusual wild plant pest, gooseweed, that tends to grow in open areas and was found in Evangeline Parish.
“Some farmers were treating it with Loyant, but I hear varying results,” he said. “A lot of times, a good stand will solve those issues.”
Webster said farmers who use the row rice practice should weigh the potential water savings against the additional expense of weed control. Herbicides with more residual activity are required. Rice herbicides were developed with the expectation that a crop would be flooded from early to midseason, he said.
Also, he said growing rice in upland conditions shifts the weed spectrum to those found in row crops, so farmers end up having to deal with weeds such as johnsongrass and pigweed.
The LSU AgCenter and the LSU College of Agriculture