NC State University graduate students win weed science awards

by Dee Shore, NC State University

Commonly referred to as pigweed, Palmer amaranth is one of the biggest production challenges farmers in the Southeast face. At NC State, scientists and graduate students are making progress toward lessening the weed’s impact in a range of crops.

Two of those students, Cole Smith and Nicholas Basinger, were recognized recently at the Weed Science Society of North Carolina for research they’ve conducted on Palmer amaranth and other destructive weeds. Smith won the society’s M.S. outstanding graduate student award, while Basinger won the Ph.D. student award. Continue reading

Arkansas farmer finds cover crops successfully keep out pigweed

In Delta Farm Press

The dominant soil type on Adam Chappell’s Cotton Plant, Ark., farm is a sandy loam. Chappell is persistent and insistent in trying to make that soil better.

He’s found the main way to do that is the use of cover crops. Continue reading

USDA research finds conservation tillage works better after first year

In Southeast Farm Press

An onslaught of the weed Palmer amaranth in the southeastern United States has left many farmers wondering if they should continue using environmentally friendly cover crops and conservation tillage or switch to conventional tillage.

Palmer amaranth is aggressive, drought tolerant, a prolific seed producer, and capable of developing resistance to glyphosate, known as Roundup. Because of that, thousands of acres in Alabama and elsewhere are at risk of being converted to conventional tillage, which may better control the weed, but increases soil erosion and threatens long-term soil productivity.  Continue reading

Weed control economical, yield-critical in corn

by Kay Ledbetter, Texas A&M AgriLife

Just how much water are weeds using in a corn crop, and is it more economical to treat or not is the focus of a Texas A&M AgriLife study.

Dr. Jourdan Bell, Texas A&M AgriLife Extension Service agronomist in Amarillo, and her Texas A&M AgriLife Research graduate student Aislinn Walton have found in early results heavy weed pressure could result in a 100-bushels-per acre yield loss on a corn crop. 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

New National Pest Alert for Palmer Amaranth released

A new National Pest Alert for Palmer Amaranth has been released. This pest alert has been approved by the national leadership of USDA NRCS to address the recent problems with Palmer Amaranth seed inclusion in wildflower and pollinator seed mixes. Ultimately, decisions must be made at the local level to address the issue of Palmer amaranth in pollinator habitats, field edges and conservation plantings.

http://ncipmc.org/action/alerts/palmer.php

Manage pigweed early for best results

In Southwest Farm Press

by Muthu Bagavathiannan, Josh McGinty, Vijay Singh, Peter Dotray , Texas A&M AgriLife

Palmer amaranth and waterhemp are two pigweed species that have become problematic in row crop production fields in Texas. Palmer amaranth is widespread in the High Plains, Rio Grande Valley, Coastal Bend and Central Texas regions, whereas waterhemp is predominantly found in the Upper Gulf Coast as well as the Blacklands regions.

Herbicide resistance in these two species is an emerging issue and Extension specialists have emphasized the need for diversifying weed management tactics to prevent or delay resistance. Because pigweeds produce enormous amounts of seeds, preventing seed production from the escapes is a critical component of sustainable resistance management. Research has shown that a single Palmer pigweed plant can produce in excess of 1.5 million seeds under good growing conditions. Continue reading

Diversity is necessary in weed control

in Southwest Farm Press

South Texas, or coastal Texas, is a unique region of the greater Southwest, marked by a sub-tropical climate, unique soils and a host of both advantages and disadvantages when it comes to agriculture.

The warmer climate allows for an extended growing season, and its relationship with the tropical Gulf of Mexico offers some clear advantages, like seasonal rains, but also unique challenges, not the least of which is an environment conducive to the rapid growth and propagation of noxious and damaging weed varieties. Continue reading

Missed the Palmer amaranth webinar? Recording is in YouTube

On Wednesday, February 15, Muthu Bagavathiannan, specialist in weed ecology and agronomy, presented a new tool for consultants, extension specialists and agents, and growers to assist with management decisions regarding Palmer amaranth, named PAM. Based in Microsoft Excel, the tool allows the user to input their rotation schedule, chosen varieties and other management practices. From those entries, the tool calculates the amount of weed seed present over a 10-year period, as well as the economic gains or losses during that period. In addition, it calculates the risk of the combination of practices and allows the user to compare up to 6 different management scenarios. The tool calculates risk based on the amount of weed seed present, which has been concluded to be the main reason for pigweed-related crop failures. 

You can get to the tool from this link.

If you would like to see Dr. Bagavathiannan’s presentation, follow this link to the YouTube recording. During the 60-minute video, he demonstrates how to use the tool and how to interpret the results.