Contact the County of San Luis Obispo Agricultural Commissioner/Weights & Measures Department at (805) 781-5910, to complain about illegal pesticide spraying. When possible, it is always best to contact the Agricultural Department while the pesticide application is occurring and to be very specific about what, when and where you observed the pesticide application. If you are leaving a voice mail or e-mail message please include information on how we may contact you in the future.