Possible Palmer amaranth infestation in Pennsylvania
An isolated infestation of Palmer amaranth has been tentatively identified in southeastern Pennsylvania. With soybean and corn grain harvest happening in the near future, please play attention to pigweeds that have survived herbicide programs in Roundup Ready crops and particularly soybean.
Palmer amaranth is quite distinctive at this stage with long (10 to 20 inches) cylindrical seed heads generally rising above the soybean crop. If Palmer amaranth seed are harvested along with the grain, the seeds can quickly spread into neighboring fields or farms.
We are still investigating this most recent occurrence, but strongly suspect that seeds were spread via contaminated manure and/or hay. This 11 minute youtube video is an OSU production helping to explain the concern about Palmer amaranth along with some management options. We will provide more information about this problem as it becomes available.