Herbicide Resistance Update on Marestail
Joshua Putman, Field Crops and Forage Specialist
Southwest New York Dairy, Livestock and Field Crops Program
Horticulture Weed Scientist, Dr. Lynn Sosnoskie, has been conducting some interesting research over the past few months. Extension specialists from all around the state collected and submitted weed specimens last fall for herbicide-resistance testing to better understand the best management practices for these weeds in field crops. We now have preliminary results from the first screening on horseweed aka marestail. Thirty populations have been tested so far and, it appears, that 27 out of 30 have resistance to the field-use rate of glyphosate (Roundup). Testing will continue with different chemistries so that we can provide growers with proper control measures. Join us next week for the Field Crop Series where we will cover topics on weeds, diseases, and insects in further detail.
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Upcoming Events
Fecal Egg Count Mobile Workshop - East Aurora
October 21, 2025 : Fecal Egg Count Mobile Workshop - East Aurora
East Aurora, NY
This workshop will explain why regularly testing fecal egg counts can help you with understanding your animals' parasite loads and dewormer resistance. Attendees have the opportunity to prepare and evaluate fresh fecal samples under the microscope and practice interpretations.
Fecal Egg Count Mobile Workshop - Jamestown
October 30, 2025 : Fecal Egg Count Mobile Workshop - Jamestown
Jamestown, NY
This workshop will explain why regularly testing fecal egg counts can help you with understanding your animals' parasite loads and dewormer resistance. Attendees have the opportunity to prepare and evaluate fresh fecal samples under the microscope and practice interpretations.
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October 31, 2025 : 2025 Annual Cornell Sheep and Goat Symposium Day 1
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Announcements
Herbicide Resistance Screening
We are screening weed species for herbicide resistance.Species we are looking for include, but aren't limited to:
- Tall Waterhemp
- Palmer Amaranth
- Marestail
- Redroot Pigweed
- Foxtails
- Common Lambsquarters
- Common Ragweed
Reach out to Katelyn Miller at 716-640-2047 or km753@cornell.edu for more information.