Keith Waldron
New York State Integrated Pest Management Program
March 4, 2013
Several calls have come in recently from across the state regarding caterpillar activity in lawns, roads, yards and fields. Jason Dombroski, Cornell Entomology’s insect identification diagnostician has also been receiving calls regarding these insects.
On warmer days caterpillars, about + 1 inch in length, have been seen crawling across lawns, roads, grass hay and even snow covered areas. Caterpillars active this time of year are likely to be the Winter Cutworm (Noctua pronuba) also called “Snow Cutworms” or Yellow Underwing larvae.
Note: These caterpillars are not true armyworms.
Pictures of the larvae can be seen at:
IDL website (http://entomology.cornell.edu/IDL).
http://www.pestid.msu.edu/InsectsArthropods/NoctuaPronuba/tabid/73/Default.aspx
From the Michigan State Factsheet: “Noctua pronuba caterpillars are sometimes called winter or snow cutworms. They are closely related to other cutworm species found in agricultural fields, feeding at the base of plants and sometimes moving up onto foliage. In large numbers, caterpillars move across fields and roads, similar to armyworm. However, unlike other caterpillar species winter cutworm is very cold tolerant, emerging even in the winter to feed. Thus if a large cutworm-like caterpillar is found late in the fall or during the winter, it is likely Noctua pronuba.”
The Michigan article continues…
“The host range of Noctua pronuba is wide and includes beets, cabbage, carrot, grape, grasses, lettuce, potato, strawberry, and tomato as well as numerous ornamental plants and weeds. In Michigan, feeding was reported on alfalfa and grass hay, Swiss chard, squash, and sugar beets.”
I was not able to find much on assessing risk or management specifics. I have not heard reports of winter cutworms being an economic concern in NY. That said, if you are finding areas of cutworm activity, it may be worth checking winter small grains, alfalfa and grass hay fields fields for potential above ground cutworm feeding. Field assessments would help identify and, if needed, help prioritize fields for potential replanting after snow melt.
The MSU factsheet mentioned above states: “There are no thresholds for winter cutworm in hay fields, but we suggest following guidelines for armyworm management (4 to 6 per square foot).”
Links For More Information:
http://blog.lib.umn.edu/efans/ygnews/2012/02/winter-cutworm.html
http://www.omafra.gov.on.ca/english/crops/field/news/croptalk/2008/ct-1108a7.htm
http://fieldcropnews.com/2012/11/tracey-is-back-and-so-are-winter-cutworm/
http://en.wikipedia.org/wiki/Large_Yellow_Underwing
