ANNAPOLIS, Md. — Palmer amaranth “has been found to cause yield losses up to 91 percent in corn and 79 percent in soybeans,” notes the U.S. Department of Agriculture. Scary statistics like that have the attention of about 75 concerned farmers, governmental officials and agricultural business representatives who attended the Season-End Palmer Amaranth Stakeholder Meeting held at the Maryland Department of Agriculture on Dec. 11.
In response to 2018 Maryland House Bill 515, a study was conducted last summer to “assess the adverse financial impact of the invasive weed Palmer amaranth on the agricultural industry in the state and determine the necessary actions each stakeholder must take to reduce the impact of Palmer amaranth and the cost of each action.”
To underscore the importance of the study and plan, Agriculture Secretary Joe Bartenfelder opened the meeting with a few remarks on the importance of the work ahead. He referred to his own first-encounter with Palmer amaranth, a memorably prickly experience.
Palmer amaranth, also known as Palmer pigweed, is a noxious, pesticide-resistant weed. It grows quickly, thrives in heat and drought, produces thousands of viable, easily fertilized seeds, and produces new plants from the roots and stems of the plant, even if the plant has been pulled from the soil. In addition, it adapts to and overcomes almost every chemical weed killer devised. Even pulling the weed by hand is iffy; the stem will break off, leaving the roots deep in the soil where they will send up new shoots. From stray segments of the plant’s stem that may be left in the field — even days and weeks after the plant has been mowed down — Palmer amaranth can produce new plants.
Mark J. VanGessel, of University of Delaware Extension, reviewed the biological characteristics and environmental impact of Palmer amaranth, offering anecdotal evidence from Delaware’s campaign to control and eradicate this noxious weed. When asked how Palmer amaranth came to be so resilient and adaptive, “sloppy genomes,” said VanGessel. The plants flexibility goes to the genetic level.
VanGessel said manure from healthy livestock did not seem to carry the fertilized seeds through their systems. He did caution, however, that livestock from organic farms might not neutralize the Palmer amaranth seeds in their guts, that further research needed to be done. Also, he reassured the attendees that mushroom compost does not carry contaminating seeds, according to the research.
VanGessel explained what areas were most vulnerable to infestation, based on Delaware’s experience.
“Both roadside and in fields; they’re both likely to harbor Palmer amaranth,” he said, “particularly along the farm trucks’ routes to the grain mills.”
He pointed out that Palmer amaranth germinates all summer long. That means that spraying must be repeated all summer. Maryland’s state highway maintenance director noted that Maryland’s road maintenance crews were taking greater responsibility for the sides of the roads and have been spraying and cutting the roadsides. The crews are also cleaning their equipment to avoid cross-contamination of farm fields.
Ben Beale, Extension agent with the University of Maryland, noted that since 2017, Maryland has taken “an integrated approach” to the Palmer amaranth problem, using continual spraying and weed picking by hand, if necessary. Beale emphasized that the weeds are spread in a variety of ways. It could happen when seeds that get caught in the tires of a combine are carried to another farm, or Palmer amaranth seeds tumble out of infested hay bales, or bird seed collected from contaminated fields are carried by crows or sparrows. Cows, chickens, deer and foxes might carry contaminants as well.
A united approach, both educating the farmers and undertaking weed eradication, was the message from Maryland Farm Bureau’s Colby Ferguson. He pointed out that the Farm Bureau would join the MDA, asking Gov. Larry Hogan to earmark sufficient money for weed control in the new budget. The summer study’s $3 million annual cost estimate for controlling Palmer amaranth might be accurate but probably not realistic, noted Ferguson. Over past years, counties have reduced their financial commitment to noxious week eradication. Only 14 of Maryland’s 23 counties currently have weed control agencies. The state budget is probably unable to support a re-establishment of a robust weed management program.
Scott Rowe, the weed control coordinator for Kent County, is on the first line of defense in the battle against the Palmer amaranth. Rowe encouraged the expansion of the education of farmers and county-level government officials. He doubts that folks realize the seriousness of the problem, and won’t begin dealing with the weed until it takes over their own acreage.
Janice F. Booth is a freelance writer in Maryland.