Resistance management still important even with new herbicides

In Southeast Farm Press

by Brad Haire

Herbicide-resistant weeds didn’t fall from the sky or rise from fields in a mutant mutiny, but they are here nonetheless. With new herbicide technologies going mainstream this season, growers must continue dogged resistant-weed management programs to preserve viable chemistries for as long as possible.

“In general, herbicide-resistant weeds become a problem over time when they are selected to survive by the overuse of a single herbicide or single mode of action. In all weed populations, there are very low levels or frequencies of herbicide-resistant plants in comparison to susceptible plants,” said Eric Prostko, University of Georgia Extension weed specialist during an American Society of Agronomy webinar “Growing for Tomorrow: How Weed Resistance Management Can Lead to Sustainability” Feb. 1 sponsored by BASF. Continue reading

PPO herbicide-resistant pigweed found in St. Louis

In Delta Farm Press

Palmer amaranth with multiple herbicide resistance is nothing new to the Mid-South. But farther north, the recent discovery of pigweed resistant to glyphosate and PPO herbicides was novel.

Where and how was the pigweed found? Continue reading

PPO-resistant pigweed spreading to Mississippi

In Delta Farm Press

A report from the 2016 Tri-State Soybean Meeting

It was big news in 2015 when Arkansas and Tennessee producers saw yet another pigweed-fighting chemistry — PPOs this time — sent to the bench. And the problem is spreading to other Mid-South states.

“We started getting calls pretty early in the growing season saying, ‘Hey, these pigweeds are blowing through Valor,’” said Tom Barber, University of Arkansas weed scientist, at the recent Tri-State Soybean Meeting in Stoneville, Miss. “Valor goes out on a lot of our acres. Continue reading

PPO-resistant pigweed, ragweed will be a major concern in 2016

In Southeast Farm Press

North Carolina State University Extension Weed Specialist Wes Everman has continually issued warning bells that resistance to PPO inhibitors is a real concern for North Carolina farmers. It is a message he will continue to deliver in 2016.

Speaking at the 2015 fall convention of the North Carolina Agricultural Consultants Association in Raleigh Dec. 4, Everman said PPO-resistant palmer Amaranth has been confirmed in Tennessee and Arkansas. “I’m pretty confident we have it in Palmer here. And we’re most of the way down the road toward confirming it in ragweed here as well,” he said. Continue reading

Arkansas farmers seeing possible PPO-resistant pigweed

In Delta Farm Press

by Bob Scott, University of Arkansas Extension Weed Specialist

There is a scientific process that weed scientists go through before we declare a weed resistant to a given herbicide. It involves looking at the suspect weed in comparison to a known “non-resistant” biotype of the same weed, looking at various rates and making sure that the resistance is heritable. The heritable part is why we grow plants out for two seasons and make sure the progeny are just as resistant as the parents.

My research counterparts at the University of Arkansas Campus in Fayetteville are working on these tests right now for PPO-resistant Palmer pigweed in Arkansas. They are not quite done yet, although it is becoming very apparent in the field that it’s here and possibly in other Mid-South states.

Continue reading