We have detected insensitivity of Colletotrichum sp. (causal agent of anthracnose of cucurbits) to FRAC group 11 fungicides (Quadris and Cabrio) in multiple commercial fields in GA. Further confirmation in our lab indicated that 70 to 80% of the isolates are either highly resistant or moderately resistant to Quadris and Cabrio. These observations suggest that managing anthracnose in cucurbits with Quadris or Cabrio is not a good option.
We have recently concluded a field trial to evaluate other options for managing this disease. Please see the list of fungicides that showed moderate level of efficacy to this fungus.
These fungicides should be used at a 7-10 day rotation in a program: Proline, Topsin, Aprovia Top, Luna experience, Bravo
Fungicides with least or no activity against this pathogen: Quadris, Cabrio, Merivon, Manzate