Prime Source Fosal Fungicide is a 2-way systemic fungicide, delivering long term defense against diseases caused by phythophthora, pythium and downy mildew. Prime Source Fosal Fungicide is also effective in the control of bacterial blights. Without any history of resistance, it will be a long term part of your turf management program. Manage the turf stress, improve the turf quality while preventing fungal infections and promoting the best plant health.