Crops

Peanut Production During a Drier, Warmer Spring

AUBURN, Ala.— Alabama peanut producers wrestled with the late-season drought during the fall of 2016. Little rainfall made for a dry harvest.

Producers hoped for relief with rain during the winter, but recent drought monitor readings show more than 70 percent of the state is already abnormally dry.  Much of the state’s traditional peanut production area is classified as abnormally dry or in moderate drought according to the U.S. Drought Monitor.

During the off-season, Alabama Cooperative Extension System professionals developed guidelines for planting peanuts during a warm, dry spring. These guidelines and other suggestions can be found in the free, downloadable resource— Alabama Extension’s Climate and Crops iBook.

Planting Risks

Planting into soils with limited moisture may be worse than delaying planting. Stand loss may occur in cases where moisture is available to germinate the crop but not to support seedling growth.

Warmer and drier conditions should remind growers of the value of cover crops, which cool the soil and allow soil moisture conservation over longer periods. Determining when to terminate the cover crop is a critical consideration under these drier and warmer winter and spring conditions. Late cover crop termination can deprive peanuts of critical soil moisture needed at planting. However, during termination, dry conditions may undermine the effectiveness of the burndown herbicide.

In a conventional tillage situation with no cover crop, growers may face difficulties deep-turning the field, if soil moisture levels are low at plow depth.

Planting Strategies

  • Under dry conditions, irrigation may be needed to promote uniform, vigorous plant stands and to cool the soil.
  • Earlier cover crop termination may contribute to soil moisture replenishment before peanut planting. However, early cover crop termination reduces overall cover biomass and subsequent soil moisture retention benefits..
  • Growers should consider adjusting termination dates to preserve soil moisture in conservation tillage at planting.

Disease Risks

Warmer conditions are associated with higher populations of root-knot nematodes and early-season outbreaks of white mold (southern stem rot).

Warmer and drier conditions at planting create a higher risk of Aspergillus crown rot.

Hot and dry soils also appeapeanutsr to scald stems of the young peanut plants, making them more prone to infection by the Aspergillus fungus. Hot and dry conditions also favor attacks from lesser cornstalk borers, which can exacerbate the impact of Aspergillus crown rot. Finally, the fungus Sclerotium rolfsii, which causes white mold (southern stem rot), becomes active quicker in warmer soils early in the gro
wing season.

If hot and dry conditions prevail during the growing season, the risk for aflatoxin is much higher, especially when the peanut pods are also affected by soilborne insects that also cause problems under the same environmental conditions.

Disease Management Strategies

  • Growers should consider planting Tifguard, Georgia-14N, and TifNV-HighO/L varieties or using nematicides in cases where peanut root-knot nematodes are present.
  • The use of Proline or Abound during early emergence (3 to 5 weeks after planting) is an effective option for managing early outbreaks of white mold (southern stem rot).
  • Fumigation with Telone II is considered the most aggressive treatment to manage peanut root-knot nematodes and also the best option to manage nematodes in cases where non-nematode–resistant peanut varieties are planted.
  • As an additional safeguard, growers should plant high-quality, fungicide-treated seed. The most severe outbreaks of Aspergillus crown rot are observed during periods of hot and dry weather and when farmer-saved seed is used.
  • To reduce aflatoxin risk, growers should irrigate when possible and manage nematodes and insect pests that damage pods. When possible, growers should plant drought-tolerant or resistant varieties and/or varieties with some resistance to aflatoxin.

Insect Risks

Drier and warmer conditions contribute to the survival of lepidopterous insects (caterpillars/moths) that overwinter as pupae in the soil. However, experts are unsure of how this enhanced survival affects the following season’s peanut crop.

Increased thrips and lesser cornstalk borer populations are also likely under these conditions.

Insect Management Strategies

  • Crop residue cover provides shade to the soil surface, reducing evaporation and absorbing more water.  By favoring plant vigor, this safeguards the plants against insects.
  • Irrigation, when available, can also be used to cool the soil and aid plant vigor.

Weed Risks

Drier and warmer conditions increase weed pressure because not enough moisture is available to activate herbicides immediately after planting. Likewise, drought-tolerant weeds are hard to control.

If climatic conditions turn wetter within prevailing warmer conditions, growers should expect heavier winter weed pressure in winter row crops and pastures. Likewise, with more host plants to sustain thrips, growers should expect a greater risk of tomato spotted wilt virus. In addition, pasture weeds may show up earlier than in normal years.

Herbicide carryover, such as Cadre carryover to cotton, may become worse in drier falls and winters.

Weed Management Strategies

  • Irrigation is an option for growers who want to improve the efficacy of their herbicide applications.
  • Weed scouting is a critical safeguard.
  • Herbicides should be incorporated to prevent photo and abiotic degradation.

Climate and Crops iBook

Climate and Crops is intended to be a comprehensive resource not only for farmers, crop consultants and Cooperative Extension professionals but also for school teachers who want to introduce their students to how farming practices are increasingly being adapted to new findings about climate variability.

Each chapter includes basic considerations associated with crop production. Additionally, each chapter covers potential climatic conditions that may occur during the growing season and how these affect each of the principal crops in terms of planting, crop growth and development, insect, weed and disease pressure and harvesting. Along with the risks, farmers are provided with the most effective management strategies to deal with each of these climate scenarios.

Learn more about Climate and Crops at http://www.aces.edu/climateandcrops.

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