The following question was sent to the P&PDL diagnosticians here at Purdue University:
Question: I have a rural lawn and pasture that is infested with Horsetail (Equisetum). Can I spray something to kill it without killing the grass or should I just cut my losses and kill it all? Do you have any recommendations as to what I should use for this application?
Answer: Horsetail does not like tillage. Therefore, the easiest thing to do is to till the pasture and re-seed.
-Tom Jordan (April 30, 1999)