Plant Pathology Greenhouse and Headhouse – UGA 4620 (1963, Category 2). The Plant Pathology Greenhouse and Headhouse is located west of the Weed Control Greenhouse along Tobacco Road. The headhouse is a one-story concrete block structure with a gable roof and new metal roofing. Like the Weed Control Headhouse, the building has small metal windows with awning sash set in the masonry openings with concrete sills. The long greenhouse is attached to the rear. The building retains integrity and is assessed as Category 2.