Critical Fungicide Management Notice (New Integration)
Mixtures of QoI-sensitive and QoI-resistant Alternaria populations were detected in aerial spore samples. The G143A mutation, which confers complete resistance to QoI (FRAC Group 11) fungicides, was identified in spore trap samples collected from potato fields in St. Johns and Putnam Counties between March 5 and April 2, 2026, as well as in samples collected during the March–April 2025 sampling period. QoI fungicides azoxystrobin-based products (e.g., Quadris, Satori, and Equation), fenamidone (Reason 500 SC), and pyraclostrobin (Cabrio EG and Headline 2.09 F). Due to the presence of resistant populations and the known cross-resistance among all FRAC Group 11 fungicides, these products are recommended to be applied in mixtures with fungicides of different modes of action to maintain effective disease control. While QoI fungicides may still provide some level of control, their use as standalone applications can increase the frequency of resistant populations, making mixture strategies necessary. Moreover, common SDHI resistance mutations (H277R, H278R, and H133R) were not detected in the analyzed samples. Review the Fungicide Application Guide for full details on resistance management: FRAC Group 11: QoI Fungicides and FRAC Group 3: SDHI Fungicides. In addition, consult the Vegetable Production Handbook in Florida for recommended fungicides mixtures and application programs.
Early Blight and Brown Spot Spores | G143A (QoI- Complete Resistance)
DETECTED
Potato Late Blight Spore
NOT DETECTED
