Vipan Kumar: Combating glyphosate-resistant weeds

Glyphosate - better known by the brand name Roundup - has been the go-to herbicide for commercial farmers in New York since it was introduced in the 1970s. However, several weed species have evolved resistance to the herbicide, and those weeds have made it into New York. Vipan Kumar, associate professor in the School of Integrative Plant Science's Soil and Crop Sciences Section, is conducting research to understand the biology of weed resistance to herbicides and to develop strategies to help farmers cope with hardier weeds.

When did weeds start to develop resistance to glyphosate?

Glyphosate-resistant Palmer amaranth, waterhemp and Italian ryegrass were first identified in southern and midwestern states in the early 2000s. These resistant species were not initially a problem for New York producers, but in 2014, resistant waterhemp was found in Seneca County. Glyphosate-resistant Palmer amaranth showed up in 2019, and my lab just documented the first case of glyphosate-resistant Italian ryegrass in Livingston, Ontario, and Genesee Counties. Even more troubling, in 2024, we documented Palmer amaranth in Ontario County resistant to multiple herbicides, including glyphosate and atrazine and further suspected resistant to chlorimuron/thifensuluron (ALS inhibitor) and mesotrione (HPPD inhibitor).

Read the full Q&A in the CALS Newsroom.