Peanut Thoughts from North of the Border David Jordan, Crop and Soil Sciences North Carolina State University
Information and Updates Peanut Notes Peanut Information Series Field days County production meetings Risk Management Tool
Topics 2019 survey Heat units in Sep and Oct ph Weed management Harvest survey from 2018
Average heat unit accumulation from 2009-2018 Lewiston-Woodville, NC 20.4 18.6 24.3 23.75 23.9 23.16 25.1 21.04 19.4 14.15 4.39 1.5 M 15 - J 15 J 16-J 15 J 16 - A 15 A 16 - S 15 S 16 - O 15 O 16 - N 1 Ten-year average (2009-2018) 2018
Influence of soil ph on peanut yield presented as percent of maximum yield Data are pooled over 3 years 100 90 Y = -275.5x + 27.3x 2 + 660.4, p = 0.0013, r 2 = 0.60, SE of mean, 2.6-3.9 80 70 60 50 40 30 20 10 0 4.6 4.9 5.3 5.8 Soil ph
Estimated economic return on investment in lime for peanut in a single season (not prorated) Adjustment with lime Dolomitic lime Economic return on lime investment ($/acre) Rate Cost 3000 3500 4000 4500 5000 5500 ph tons/acre $/acre 4.5 to 5.8 1.0 46 251 300 350 399 449 498 4.9 to 5.8 0.8 37 225 269 313 357 400 444 5.3 to 5.8 0.4 18 140 167 212 238 265 273
4 of 125 populations with suspected resistance to PPO herbicides One population with possible resistance to glyphosate and herbicides that inhibit ALS, PPO, and HPPD
Weed Control in Peanut Overlapping residuals has been a component of success Intensive weed control early in the season is important Controlling weed escapes later in the season is just as expensive and less effective than upfront PPI/PRE herbicides Spraying large Palmer amaranth multiple times with PPO inhibitors later in the season most likely hastens development of resistant populations
Weed Control in Peanut Effective PPI and PRE herbicides need to be supported with early POST applications of Gramoxone plus Basagran with residual herbicides Warrant, Outlook, Zidua, or Dual materials are effective residual herbicides applied with Gramoxone plus Basagran
Thrips Control in Peanut Effective systemic in-furrow insecticides often need to be supported with early POST applications of acephate Warrant, Outlook, Zidua, or Dual materials are effective residual herbicides applied with Gramoxone plus Basagran These combinations are often applied with acephate for thrips and weed control
Current Knowledge of Co-Application for Thrips and Weed Control Many studies with Dual materials mixed with Gramoxone plus Basagran plus Acephate Some work with Outlook, but this herbicide is used less frequently Some work with mixtures of Warrant or Zidua mixed with Gramoxone plus Basagran plus Acephate
One Day after Treatment Paraquat plus bentazon Paraquat plus bentazon plus pyroxasulfone
One Day after Treatment Paraquat plus bentazon Paraquat plus bentazon plus dimethenamid-p
One Day after Treatment Paraquat plus bentazon Paraquat plus bentazon plus acetochlor
One Day after Treatment Paraquat plus bentazon Paraquat plus bentazon plus S-metolachlor
Two Weeks after Treatment Paraquat plus bentazon Paraquat plus bentazon plus pyroxasulfone
Two Weeks after Treatment Paraquat plus bentazon Paraquat plus bentazon plus dimethenamid-p
Two Weeks after Treatment Paraquat plus bentazon Paraquat plus bentazon plus acetochlor
Two Weeks after Treatment Paraquat plus bentazon Paraquat plus bentazon plus S-metolachlor
20 18 16 14 12 10 8 6 4 2 0 Injury from Southern Corn Rootworm Data are from 25 trials during 2016-2017 Scarring (%) Yield loss threshold, about 25% scarring Non-treated Prevathon Lorsban
Injury from Southern Corn Rootworm Data are from 25 trials during 2016-2017 Pod yield (lbs/acre) Yield loss threshold, about 25% scarring 5000 4500 4000 3500 3000 2500 2000 1500 1000 500 0 Non-treated Prevathon Lorsban
Pyrethroid resistance in corn earworm Presence of tobacco budworm Points to: Use of more effective but certainly more expensive chemistries to control the foliar-feeding insect complex
How many days from digging? Assume soil is in good shape, no hurricanes and little to no leaf spot Write the number on the survey sheet
Number of Growers from All States Stating that Peanut will be at Optimum Maturity in a Certain Number of Days Based on the Pod Blasting Sample 30 25 20 15 10 5 0 Percent of Growers Days to Optimum Maturity Based on Pod Blasting Samples
Peanut Yield (percent of maximum) and Digging Date Data are pooled over varieties and seeding rates 100 Planted May 16-18 80 60 40 20 Sep 8-9 Sep 18-20 Sep 29-30 Oct 10-14 0 2016 2017 Sep 7 Sep 18
Percentage of Farmers Practice NC SC VA Prohexadione calcium 56 13 51 Guidance 38 79 32 Both 19 10 8