Manitoba soybean growers have a new herbicide option.
Nufarm’s Valtera, with the active ingredient flumioxazin, controls a number of broadleaf weeds early, while suppressing annual grasses such as green foxtail, says Myles Robinson, the firm’s Manitoba sales manager.
“Soybeans do not like competition” and that’s why early weed control can pay off in higher yields, said Robinson.
Flumioxazin has been registered in the U.S. for 14 years and sold under the name Valor. Trials there show when flumioxazin and glyphosate are applied as a pre-crop burn-off, per-acre yields are three to seven bushels higher than when glyphosate is applied once or twice.
Valtera can be applied early as a pre-plant burn-down with a partner such as glyphosate, or as a pre-emergent just before or just after seeding. It should be applied no later than three days after soybeans have been planted, Robinson stressed. If the soil has cracked due to germination or soybeans have emerged severe crop damage will occur.
No more than 85 grams per acre of flumioxazin should be applied during a single growing season.
“It’s an absolutely great product if you want to grow non-GMO soybeans,” Robinson said. “You’ll see somewhere between 30 and 56 days of residual weed control.”
Despite residual control, there are no cropping restrictions after 12 months at the longest. A four-month interval is required before planting treated fields to spring or winter wheat. Field corn, sunflower, sorghum, dry beans and canola can’t be planted for nine months after a low rate of Valtera. At the higher rate, alfalfa, barley and canola can’t be seeded for 11 months.
Valtera is applied to the soil surface and not worked in, and so can be used in minimum- or zero-till fields. It requires one-quarter to one inch of rain to get the herbicide into the soil and working, Robinson said, and more if there’s a lot of crop residue.
“This one doesn’t require any incorporation at all,” he said. “In fact, dragging the harrows over it is actually detrimental to good weed control.”
Flumioxazin is a Group 14 herbicide providing farmers with another rotation option. Rotating herbicide groups and tank mixing different herbicide groups are recommended to delay the development of herbicide-tolerant weeds.
Valtera isn’t meant to necessarily replace glyphosate, but it can reduce its application from two or three times in crop to one or two, Robinson said.
“With all the issues around glyphosate tolerance (in weeds), I think it’s going to become more and more important to rotate into some of these new groups,” he said.
Common ragweed, pigweed/waterhemp, lamb’s quarters, black nightshade and seedling dandelion are on Valtera’s Canadian label. The U.S. label includes more weeds, such as volunteer canola, some of which may get added to the Canadian label, Robinson said.
Valtera should be applied with 10 gallons of water per acre, and can be tank mixed with CleanStart or Credit45 (glyphosate) when doing a burn-down. Valtera alone has some burn-off activity. It’s rain-fast one hour after application. Burn-down results are best if it’s warm and sunny when Valtera is applied.
If applying before seeding, a low-disturbance seeder should be used as the more the soil is disturbed, the poorer the weed control. If a lot of soil disturbance is expected, apply Valtera after seeding, but no later than three days.
The rise of glyphosate-tolerant weeds in the U.S. has prompted a rise in pre-emergent herbicide use in soybeans, Robinson said. About 35 per cent of U.S. soybeans receive a pre-emergent herbicide and Valor accounts for 48 per cent of those acres, he said.
“That change has happened because there has been just an intense use of glyphosate down there and now they have a lot of weed species really giving them some challenges because they have become tolerant to glyphosate,” he said.
Valtera comes in a case of four bottles (2.27 kg per bottle) at a suggested retail price of $2,120.
One bottle treats 40 acres at a cost of $13.25 an acre.