In-Furrow Application of Fluopyram Allows Delayed Foliar Fungicide Initiation for Management of Leaf Spot Diseases of Peanut.

For peanut (Arachis hypogaea) production, in-furrow applications of the SDHI fungicide/nematicide, fluopyram, are made primarily for management of root knot. Fluopyram is also effective against early leaf spot (Passalora arachidicola) and late leaf spot (Nothopassalora personata). The purpose of this study was to determine whether in-furrow applications of fluopyram would allow omitting early season foliar fungicide applications for leaf spot control. Field experiments were conducted in Tifton, GA in 2022-2025. In all experiments in-furrow applications of fluopyram provided extended suppression of leaf spot epidemics compared to the nontreated control. Leaf spot control achieved when the first two foliar fungicide applications of chlorothalonil were omitted after in-furrow application of fluopyram was like or better than that of full season applications of the standard fungicide chlorothalonil treatment in all years. In 2023-2025, additional two- or four-week delays in initial application provided leaf spot control similar to that of the full season chlorothalonil treatment. Results indicated that in-furrow application of fluopyram could replace two or more foliar fungicide sprays and still maintain control as good as that of full season application of chlorothalonil.