Fungicide programs should be initiated at the R3 stage of peanut development but no later than July 10 even if peanuts have not reached the R3 stage. R3 is the stage when the first pegs have entered the soil and started to swell. We currently do not recommend any differences in our approach to managing leaf spot and stem rot with our current Virginia market types. We know less about the runner market types grown in the region (they were developed for the southeastern US.) For this reason we suggest starting your fungicide program at R3 or no later than July 10 regardless of growth stage. The majority of fungicides are applied either on a bi-weekly schedule or based on the leaf spot advisory system (see previous Peanut Note from Dr. Shew for details.) Programs with Miravis plus either Elatus or Convoy (both at high rates) can provide up to four weeks of control. Keep that in mind if you are using the advisory system for leaf spot disease.
Initiating Fungicide Sprays Peanut Notes No. 109 2021
(Updated: June 28, 2021, 11:36 a.m.)