As we leave the university’s campus behind and head east out of Champaign-Urbana, my hometown, a soybean field comes into view, its tall, dark green stalks now overgrown with thick, spiky vegetation that reaches nearly to chest level.
The problem lies precisely here. That’s all water hemp, proper, there? My guess is that it has been sprayed at least as early as, if not no later than.
Water hemp, a highly invasive species, has the ability to rapidly colonize and infest almost any crop, growing up to an additional inch per day. Female plants are particularly prolific, producing massive quantities of thousands of seeds that can lead to devastating reinfestation. Hailing from the Midwest, this invasive species has experienced a significant proliferation in recent years due to its demonstrated resistance to at least seven distinct types of herbicides. Season-long infestations of water hemp can lead to a devastating 44% reduction in soybean yields and a significant 15% decrease in corn yields.
Despite the challenges, many farmers are managing to cope. While two distinct teams of herbicides may coexist effectively against water hemp. As resistance to change manifests more frequently in various forms.
As Kevin Bradley, a plant scientist at the University of Missouri, notes, “We’re starting to witness failures in weed management.” It’s unclear what you mean by this statement. Can you provide more context?
The situation elsewhere is far more dire.
“Time is of the essence,” stresses Dr. John Smith, a renowned professor of plant sciences at the University of Tennessee, “We urgently need a fundamental shift in weed management – and we can’t wait any longer; weeds are gaining ground just as quickly.” “It has reached an increasingly crucial point.”
On the rise
According to Ian Heap, a renowned weed scientist, more than 500 documented cases of this phenomenon have been recorded across approximately 273 distinct weed species and continue to grow in number. Weed populations have evolved resistance to 168 distinct herbicides, with 21 out of the 31 identified “modes of action” compromised, highlighting the specific biochemical target or pathway a chemical aims to disrupt. Many herbicides exhibit shared modes of motion.
One of the most pernicious invasive species plaguing the Southern United States is Palmer amaranth, a rhubarb-red-stemmed cousin to water hemp that consistently vexes Steckel and his colleagues. Researchers have identified populations of resilient weeds that exhibit resistance to nine distinct classes of herbicides, posing a significant challenge to effective weed management. The invasive species can grow at an alarming rate of over two inches per day, ultimately reaching up to eight feet tall and potentially monopolizing entire fields. Native to the arid desert Southwest, this resilient species is characterized by a robust root system that enables it to withstand prolonged droughts with remarkable tenacity. If inclement weather or your daughter’s wedding forces a brief delay in application, you’ve probably forfeited the opportunity to control its chemical development.
