Preventative biological fungicide, university-developed and tested for over 20 years. Active ingredient Trichoderma harzianum strain T-22 (KRL-AG2) grows onto plant roots and forms a natural bond, "shielding" them from pathogens such as Pythium, Rhizoctonia, Fusarium, Cylindrocladium, and Thielaviopsis. RootShield® Plus includes a second active ingredient (Trichoderma virens strain G-41) to protect against Phytophthora, which typically afflicts tomatoes and other nightshades. May be applied to seeds, transplants, or used as a soil drench. Six-month expiration date. Always buy a fresh supply to ensure viability.