Should tenant pay for Exterminator?

[Bob Randolph]

I'm an "Accidental Landlord", I had to foreclose and inherited month by month tenants.  Haven't gotten a new lease signed with them yet.  They are hard-working folks (A husband & wife in their 60s) that pay on-time and in  full.  On recent inspection I saw lots of "Baby roaches"...  They don't see this as a problem but I'm grossed out and want to get an exterminator in their at least quarterly.  My question is should I increase their rent to cover the cost?