The Bedbug problem after 6 months of movein

[Marita Jojo]

My tenant moved last year and after 6 months of move-in complaining of bedbugs. The previous tenant stayed for 14 months and I checked had never had this issue. I have in the past asked these tenants to clean up as they seem to be poor housekeeping going on. These tenants keep on picking stuff from the curbside that I have asked them in the past to stop as can bring in all the pests. What do you do in this situation ? Is this landlord's responsibility after 6 months of move-in ?