Scientists find time of day makes a difference with some herbicides

In Southeast Farm Press

What if a cotton producer needed to spray early in the morning or late in the afternoon or at night? Does the time of day a herbicide is applied make a difference in how well it works? A group of weed specialists studied this and what they found surprised them.

The group included scientists from the University of Georgia, Louisiana State University, Mississippi State University, North Carolina State University and the University of Tennessee. Continue reading

More precautions needed when spraying with dicamba and 2,4-D

From the Weed Science Society of America

New resistant soybean and cotton cropping systems based on the synthetic auxin herbicides give farmers new options for managing Palmer amaranth and other broadleaf weeds resistant to glyphosate. But scientists with the Weed Science Society of America (WSSA) say special precautions are necessary. Auxin herbicides are known to drift and to cause harm to sensitive, off-target broadleaf plants.

“Concerns about drift led the U.S. EPA to issue time-limited registrations for the auxin herbicides dicamba and 2,4-D of two years and five years respectively,” says Kevin Bradley, Ph.D., past president of WSSA and associate professor at the University of Missouri. “The approved product labels have considerable detail on management of drift and other risks and must be carefully followed to reduce off site movement. Unless growers show they can use these herbicides as labeled, the registrations could easily be revoked.” Continue reading

University of Illinois Plant Clinic announces Palmer amaranth seed ID and herbicide resistance plant tissue testing

Last summer, farmers in the Midwest got an unwelcome surprise after planting native seed on Conservation Reserve Program acres. Palmer amaranth is an aggressive and hard-to-kill weed. As a possible solution, some states declared Palmer a noxious weed, which prohibits its sale and transport.

The typical testing method involves growing a sample of seeds until the plants are large enough to be identified, but this is a slow and potentially unreliable process. Pat Tranel, molecular weed scientist at the University of Illinois, said growers are calling and telling him, their businesses are up in the air because of this.” Unless they have a way to certify their product is Palmer-free, they can’t sell it,” said Tranel. There is a company that tests individual seeds using DNA sequencing, but charges $100 per seed. Continue reading

Weeds could develop resistance to dicamba in three generations

In Delta Farm Press

What happens if farmers follow the same practices they have when other new herbicide chemistries have come on the market over the last several decades?

If they’re not careful, they will simply replace one herbicide with another, as they did with Prowl and Treflan, ALS herbicides, glyphosate and most recently with PPO inhibitors such as Flextar and Reflex. Continue reading

If your weed control is working, it’s time to change it, says weed scientist

in Delta Farm Press

It might seem like an odd recommendation to make – to change something if it’s working.

But that’s what Bob Scott, Extension weed scientist with the University of Arkansas System Division of Agriculture, said during a presentation at Pigposium 3, held at East Arkansas Community College in Forrest City. Continue reading

Growers must be careful when using new herbicide technologies

In Delta Farm Press

Rules surrounding new weed-fighting technologies don’t make for a short, or uncomplicated, list, says Ples Spradley.

First off, “Applications of products (Xtendimax, Enlist Duo and Engenia) shall not be made to Enlist or Xtend seed technologies without’” completing new training, the Arkansas Extension pesticide safety education specialist told the crowd at the recent Pigposium 3 in Forrest City, Ark. “If you’re an applicator – private, commercial, non-commercial or commercial applicator technician – and will use those herbicides on those technologies, you must go through our training. The new regulations state that you cannot apply Xtendimax in Arkansas between April 15 and September 15, with a limited exception for pasture applications.” Continue reading

What do farmers think about resistant weeds?

in Southeast Farm Press

Both scientists and regulators have had a lot to say about the growing problem of herbicide resistance and how weed management techniques need to change in response. However, there have been few organized opportunities for farmers to make their voices heard and to share their experiences in managing herbicide-resistant weeds.

This is changing with a series of seven regional listening sessions sponsored by the Weed Science Society of America, the United Soybean Board and the U.S. Department of Agriculture Animal and Plant Health Inspection Service. Farmers across the nation are being invited to share their challenges, successes and opinions. Continue reading