 you're not doing really anything for the face flies or the stable flies but you are inhibiting the development of the horn flies which are on the back and the shoulders and it can be you know hundreds if not thousands of flies sometimes so that that that's something you have to start early sometimes we make the mistake though of putting in fly tags in april and i understand that's the only time you can get it done we have put them in way ahead of when the actual fly season is and so by the time the fly season comes