WBLDon,
I note you live in Minnesota in the USA. Depending where in the world you live, what eats your horn may well differ from what eats someone else's horn in a different place in the USA or elsewhere in the world. Your best guide as to what insect(s) is/are infecting or are likely to infect your horn, is to contact your local Natural History Museum and speak to either their resident Taxidermist or Conservator. They will be able advise you what to use to keep your local critters at bay. There are a large number of insect species that attack horn including various species of Micro-Lepidoptera (small moths)to Coleoptera (small beetles)and just about everything in between. Local knowledge is always best.
Good luck,
Harry.
