This publication, produced by the Maine Organic Farmer & Gardener Association (MOFGA), reports on a 2023 organic fungicide trial on winter squash at MOFGA's Common Ground Education Center. Testing sulfur, copper, thyme oil, and bacterial bio-fungicides, results confirmed sulfur's effectiveness against powdery mildew and copper's general foliar disease control, while expensive newer bio-fungicides showed more limited advantages.