perhaps these are the piles of weed and dead branches I was gathering in the dream to burn, represent old useless karma.

First the old man showed me the field and that the weeds were ready for harvesting,because they were taking over his land. Then I turned and saw the extermintaors coming from behind us,and it was two men,the guys on the Ghostbusters with the extermination backpacks. They spoke and said.."This ought to get rid of them weeds once and for all"