Scout Fields Now For Palmer Amaranth

 

The frequency of Palmer amaranth infestations in Ohio has been holding relatively steady again into this year.  We have mostly an isolated field or patch in about 10 counties, with the exception of two small epicenters of Palmer amaranth - far southern Scioto County and an area along the Madison-Fayette County line north of Jeffersonville.  Several new infestations of Palmer amaranth in soybeans have been reported over the past several weeks though.  

 

 

 

 

It was also found in a first-year hayfield, where cutting and competition from the alfalfa/grass stand will likely keep it under control in coming years.  None of these appear to have produced viable seed yet.  This is typical based on our Palmer seed collection over the past several years, and it may be due to the early-season control provided by preemergence soybean herbicides.  This is a good thing, since it provides a window to remove plants from fields before viable seed are produced.  The number one recommendation for managing Palmer amaranth in Ohio is to prevent it from getting established, because it can take over a field faster than any other annual weed we deal with.  

 

Taking the time to remove any Palmer plants from fields now will go a long way toward maintaining the profitability of farm operations (same goes for waterhemp really, which is no picnic to manage either).  There is information on Palmer amaranth identification on most university websites, including ours:

 

http://agcrops.osu.edu/specialists/weeds and http://u.osu.edu/osuweeds/ .  Or Google “Palmer amaranth” and then use the “images” link.  The dead giveaway at this time of the year is the long seedheads, and those on female seed-bearing plants are extremely rough to the touch.  We recommend the following as we progress from now through crop harvest: