A while back the city planted loads of different varieties of ash trees & now a lot have gotten the ash borer & are dying. I have a common green ash that I received as a 'freebie' in a plant order years ago & it is now a nice shade tree but it also has the borers. Many branches dried up & died despite flushing the borer holes with Dursban (now outlawed here). I finally heard of ACE plugs that one hammers into holes drilled into the bark of the tree. After severely pruning the dead branches, this year the tree has leafed out wonderfully & no new dead wood! Don't know how long these plugs will be lawful but so far it seems we have extended the life of our nice shade tree. Anyone heard of these plugs?