Sussex County farmers are being asked to stay on the lookout for a pair of plant species that experts say is quickly invading southern Delaware.
Palmer amaranth and Texas panicum recently become the first plants added to the Delaware Department of Agriculture’s noxious weeds list in more than 25 years.
“Both of these weeds, if left unchecked, can have a significant impact on agricultural production by reducing competing crops and farmers’ overall yield,” said Mark VanGessel, a plant and soil science professor and extension specialist at the University of Delaware’s Carvel Research and Education Center near Georgetown. “I’ve already seen fields where the yield has been reduced by 25 to 30 percent because of these weeds.”
Under the advice of the state’s weed advisory committee, Delaware Secretary of Agriculture Ed McKee officially made the Palmer amaranth and Texas panicum just the fifth and sixth plant species included on the state’s noxious weed list earlier this month. They join Johnsongrass, Canada Thistle, Burcucumber and Giant Ragweed, all of which were labeled as noxious weeds in the state between 1970 and 1986.
VanGessel, who serves on the advisory committee, said the intent is to raise awareness and inform farmers of the proper measures for combating the invaders.
“We don’t want a list that just includes every problem weed out there,” he said. “Our intent in including these two now is to get farmers to make a conscious effort to spot them, and a concerted effort to control them, before they can spread to the point where they get out of hand.”
Texas panicum is a grass species that typically grows in the spring and summer and can reach heights of up to three feet, most commonly causing harvesting issues in corn and soybean fields. One of its most readily identifiable characteristics is the small, velvety hairs that grown on both sides of its leaves, VanGessel said.
The densely growing weed first appeared in Sussex County about a decade ago and now can be found as far north as Smyrna, he said.
The presence of Palmer amaranth is more localized to eastern Sussex County, but poses a potentially greater threat to local agriculture because it has shown a resistance to certain herbicides, VanGessel said.
“There are ways to control it, but it requires more management than farmers might be used to,” he said. “The best time to try to control it is when it’s 3 to 4 inches tall. Beyond that, it can be very difficult.”
Similar to pigweed, the Palmer amaranth can grow up to 8 feet tall with stalks several inches in diameter, making it hazard to mowers, harvesters and combines. It is most readily identifiable by its long, prickly seed heads, which alone can grow up to 2 feet in length.
Page 2 of 2 - Both the Texas panicum and the Palmer amaranth germinate throughout the year and are equally adept at surviving in drought-like conditions, making them particularly threatening in dry, hot summers like the one Delaware just experienced, VanGessel said.
“When crops are already struggling and not providing a lot of shade cover, these two weeds can really thrive,” he said. “That’s one of the reasons we want to make farmers aware of them now.”
A spokesman for the state department of agriculture said the agency is helping farmers manage the weeds by providing them with information on identification, management and control, including tips for proper mowing, tillage and herbicide application.