COMMUNICATION is key with all parties.

Endless communication.

I notified my realtor about this and she expressed three concerns: (1) if I list her info in the letter, it could be construed as her soliciting another agent's client; (2) my communicating with the seller directly complicates my current agreement with my agent (she used the analogy of me hiring an attorney and then communicating with the other party directly instead of through the attorney); and (3) I may inadvertently do or say things that could be construed as practicing real estate without a license.Thoughts?  

He was barely even communicating with me at all. 

Good advice coming in from the above posts; I'm of a similar mindset as Jennifer in that clear communication around this helps to set the expectations.

This year I got my license and would love to read some book on communication, sales and marketing.

When communicating with tenants, what are your favorite apps?

This year I got my license and would love to read some book on communication, sales and marketing.

Effectively Screening tenants, following fair housing requirements of course, is THE “key” to prevent problems, as is proactive management and direct communication.

I think some of it also depends upon timing (ie. when the infestation happens/became noticable).In many instances, there's a lot they can do to try and mitigate some of that risk of another infestation happening (ie. sealable, odor containing/closed trash cans, taken out regularly; regular cleaning of the apartment space; ensure food is in tightly sealed containers, even if in the refrigerator; early communication about any standing water or wood rot; wash bedding frequently -  a lot of people eat in bed, and this is an easy way to attract insects and pests because oftentimes most people don't wash their bedding nearly enough).