nellie stevens holly

Question

20 year old Nellie Stevens holly tree has square holes eaten into bark around circumference of trunk has several identical rows – ten feet off ground and 15 feet off ground with sap leaking from these areas.

Answer 1

I suspect that you are looking at either carpenter bee damage or borer damage. A common borer that attacks holly is the Redheaded Ash Borer. These articles will help you determine which it might be: http://www.ento.okstate.edu/ddd/insects/redheadedashborer.htm

http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7417.html