Should we pay for an exterminator?

I'm new to Houston. The property manager of an RV Park wants us to chip on for pest control, because someone has been leaving food out for animals. We've been fighting roaches for months and have been constantly spraying for them. We initially thought it was because the grass would get cut about once a month and started cutting our own area. We saw roaches all over one person's area with all the food. I mentioned it to the manager and now they was us to chip in for an exterminator. Is that not what rent is for? We have to cut our own grass and pay for an exterminator!?