The following slide set includes information on the relationship of fungicide sprays and peanut yield when digging is delayed. The "rescue" treatment applied at about 15% leaf spot incidence (lesions apparent) was helpful in 2024, but the magnitude was lower than what we observed in 2023. Depending on the year, fungicide applied later in the season can decrease defoliation and protect yield, especially if weather conditions are favorable for disease and digging is delayed because of soil conditions or logistical challenges growers face.
Note that the "rescue" treatment in this case (Provost Silver plus microionized sulfur) has a degree of curative activity (prevents some lesions from forming even after infection has occurred.) On the peanut maturity charts, I make the statement that once you get to 20% incidence, fungicide is unlikely to help. When I included that statement, my mind was on chlorothalonil and not fungicides that offer a degree of curative activity. We printed several thousand of these charts, so I suspect I'll be making this disclaimer for years to come.