Routine would also mean that you would have somebody come in to spray for these types of insects. If you chose not to have a regular spraying then you are not fulfilling the routine pest control. Over time bees, insects, termites could accumulate (and could go unnoticed until it becomes a problem) at the property and would be the responsibility of the tenant in this case.
If you are doing a routine pest control, I would ask them what they consider routine spraying (if it includes bees or not). They would be the experts in this case, if they say that "bees are not common to spray for" it could mean that this is not a routine pest problem and should be covered by the landlord.
Footnote: I am not a lawyer or legal expert nor am I giving legal advice. If you need further clarification I could consult a lawyer that is familiar with real estate law and find out what that definition would mean in a court.
I would imagine bees are not of the routine pest control and would suggest pursuing your landlord more aggressively. Also, you might seek help through an attorney who is familiar with the landlord tenant act.
Though you may consider your landlord "cheap" he/she certainly values you as a tenant and your continued rent payment. Perhaps you could provide the landlord with a quote from a local exterminator with information from the professional about the seriousness of the problem. An extension of the current lease or other property improvements might also help in bringing the landlord to the table to assist you. Best of luck!