If you have a vacuum cleaner that would reach that far that has a throw away bag.....then throw it away......do that and use a fruit tree spray to spray inside.............is this in the root or in a branch.......after you spray in the hole..........let that dry and use spectrcide tree repair spray to seal that. Hard to say it it will make it..........in the fall when all the leaves fall off use dormant oil.........I also thought that you could make up a small amount of SEVIN to spray in that hole only...............in the spring start early with a spring dormant oil mix.............up the the bud stage..........once the bud opens stop and just spray the trunk.