By Blake Jackson
Herbicide-resistant weeds are emerging as a serious challenge for farmers in New York, as invasive species continue to spread beyond their traditional regions.
According to Krisy Gashler, at College of Agriculture and Life Science, glyphosate-resistant Palmer amaranth, waterhemp, and Italian ryegrass were first identified in southern and Midwestern states in the early 2000s.
While these weeds were not initially a concern in New York, resistant waterhemp was discovered in Seneca County in 2014, followed by Palmer amaranth in 2019. More recently, glyphosate-resistant Italian ryegrass has been confirmed in Livingston, Ontario, and Genesee counties.
In 2024, researchers also identified Palmer amaranth in Ontario County with resistance to multiple herbicides, including glyphosate and atrazine, with suspected resistance to additional herbicide groups.
These weeds are often introduced through contaminated animal feed, birdseed, manure, uncertified crop seed, or farm equipment transported from other regions. Changing climate conditions have further supported their establishment.
A major concern is that many of these invasive populations already carry resistance traits, making them difficult to manage.
Glyphosate remains the most widely used herbicide in New York, with many soybean growers relying heavily on a single application. However, resistant weeds are reducing its effectiveness. These aggressive species can cause crop losses of up to 80-90% under favorable conditions.
They grow rapidly, sometimes exceeding six feet in height, and produce large quantities of seed, outcompeting crops for essential resources. In severe cases, infestations can even disrupt harvesting and reduce grain quality.
To combat this issue, experts recommend a more integrated management approach. Farmers are encouraged to use pre-emergence herbicides, diversify crop rotations, and incorporate cover crops like cereal rye or triticale.
Additional strategies, including forage integration, harvest weed seed control, and mechanical methods, can further help limit the spread and impact of resistant weeds.
Photo Credit: gettyimages-zoomtravels
Categories: New York, Crops, Education