Glomerella leaf spot, caused by a Colletotrichum spp. complex, results in leaf and fruit spots on genetically susceptible apple trees, leading to defoliation and unmarketable fruit. Axios (ipflufenoquin), a new fungicide with a novel mode of action, was evaluated for its ability to control this disease in a 24-year-old Malus domestica ‘Golden Smoothee’ orchard in Blairsville, GA. The standard treatment involved fungicides effective against Colletotrichum spp. and adhered to resistance management practices. This standard protocol performed as expected, significantly reducing Glomerella leaf spot compared with untreated trees. While Axios demonstrated some efficacy, it did not match the level of control achieved by the conventional chemical fungicides used in the standard regimen.
Melton et al. (Thu,) studied this question.