Developers: If an IPM plan is required, developers should be informed during the development review process. It is then their responsibility to submit, and comply with, a plan. If the land is then sold, it is their responsibility to communicate the need for the new land owner to abide by the plan.
Homeowners: If you own an individual parcel of land that requires a site plan review and no developer or previous owner has submitted an IPM plan, then it is your responsibility to do so.