Peanut disease management trials were conducted at the Oklahoma State University (OSU) Caddo Research Station near Fort Cobb in 2020. The Spanish peanut cultivar Ole was planted on May 6, 2020, in 36-inch rows. Cool temperature slowed development in 2020. Even with the slow start peanut yields exceeding 5,000 pounds per acre. All peanut were treated with Prowl H₂O at 1 quart per acre + Valor at 2 ounces per acre preemergence  followed by Gramoxone 8 fluid ounces per acre + Dual Magnum 1 pint per acre early postemergence followed by Select 16 fluid ounces per acre POST, along with hand weeding to maintain the plots weed free for the duration of the trial. Peanuts were fertilized based on recommendations from OSU soil testing and were irrigated on an as needed basis. 

 

Two trials were established to evaluate fungicides, primarily for control of leaf spot in Spanish peanuts. In each trial, up to five applications were made, starting in mid-June. This coincided with the following application timings: POST1 (P1) – June 17, POST2 (P2) – July 2, POST3 (P3) – July 20, POST4 (P4) – Aug. 4, POST5 (P5) – Aug. 21. Peanuts were dug in October and harvested on Oct. 21. 

 

Trial PFCS20-09 was established to evaluate peanut disease response to Lucento in the Spanish peanut (Ole). Fungicides were applied to peanuts to evaluate their effects on controlling leaf spot and Southern blight and their effects on peanut yield. Treatments evaluated Lucento applied with either Bravo or Topsin + Penncozeb. These treatments were then followed by either Folicur or Abound. Fungicides applied, rates and timing can be viewed in Tables 1 and 2. All fungicide programs reduced leaf spot when compared to the untreated control (Table 1). While Southern blight occurrence was extremely low in this trial, it was reduced with fungicide applications when compared to the untreated control (Table 2). Yield was increased with all fungicide programs when compared to the untreated control (Table 2). 

 

Trial PFCS20-10 was also established to evaluate peanut disease response to different timings of Lucento in Spanish peanut (Ole). Fungicides were applied to peanuts to evaluate their effects on controlling leaf spot and Southern blight and their effects on peanut yield. Lucento was applied either P1 and P3 or P2 and P4. These were then applied in a treatment regimen that included Bravo, Bravo and Folicur, or Bravo and Headline. Fungicides applied, rates and timing can be viewed in Tables 3 and 4. All fungicide programs reduced leaf spot when compared to the untreated control (Table 3). Southern blight incidence was very low and was not affected by fungicide treatments (Table 4). Yield was increased with all fungicide programs when compared to the untreated control (Table 4).