>Hi. Last fall I treated my 140 colonies with extender patties for tracheal >mite and AFB control. I am noticing that many colonies now have about half >the pattie remaining, but I'm not sure if this terramycin is still active. >Should I remove the residue and treat again, or will the residue be >effective thru early spring? > >Does anyone have knowledge or an opinion regarding terramycin stability to >help with the above question? Thank you. > >Jim King, Riegelsville, PA I'd leave it, as long as the TM wasn't long past its expiration date. The shortening protects it from moisture, so I presume it's more or less "sealed" and stable. Just replace it when it's all gone. Actually, sometimes I find portions of patties that are all dry and crusty which the bees have tried to propolize over, or its covered with dirt. I'll either mix it up a little, adding some new stuff, or just chuck it and replace it.