Bacon County Ag Update

Peanuts are moving into the “Critical Period”

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Most of the peanut crop is moving past the 60 day mark, and we are into the more critical time when proper inputs for making a good peanut crop are vital. Staying on a proper fungicide program, and monitoring insect pressure will be crucial to maximize the yield potential in your peanuts. Please read these excerpts from some of our UGA Extension Peanut Specialists.

Here is some comments from Dr. Scott Tubbs, UGA Peanut Agronomist

The USDA Crop Progress Report for Georgia says peanuts are 77% blooming and 42% pegging as of July 6.  The report from June 1 also showed that we were 85% planted by June 1.  Thus, the timeframe that I like to call the “grace-period” for peanuts (between emergence and blooming) is over for most of the crop.  Considering most of the harvested crop is set between 40 and 90 days after planting, the management decisions and timing over the next month to six weeks are going to be what determines the full yield potential.   Many parts of Southwest GA and the primary peanut producing areas have had little to no rain in the last two weeks as much of the crop is entering the critical phase of initial pod set, when most of the densest, highest grading peanuts are going to be formed.  The water requirement at this stage is entering or already in the 1.5 inch per week range, so if irrigation is possible, it is important to not fall behind since subsoil moisture is being depleted rapidly with no rainfall in two or more weeks now in some areas.

Here are some comments from Dr. Mark Abney, UGA Extension Entomologist

Heading into July there are some potential insect issues we should be watching in the 2014 peanut crop. Almost every peanut field will have some foliage feeding caterpillars, but fields where a broad-spectrum insecticide like acephate (Orthene) or chlorpyrifos (Lorsban) was used early in the season are at increased risk. Monitoring caterpillar populations is particularly important in these higher risk fields. A lot growers in Georgia have grown accustom to making automatic insecticide applications for caterpillars, but in many cases these sprays are not necessary. Vigorously growing peanut plants can tolerate a great deal of defoliation with no reduction in yield. The current threshold for caterpillars in peanut is 4 to 8 larvae per row foot.

Lesser cornstalk borer (LCB) and twospotted spider mite (TSSM) are two of the most difficult to control pests of peanut, and both have already appeared in Georgia fields this year. Hot, dry conditions favor the development of LCB and TSSM infestations, and the weather will play a major role in determining just how big a problem these pests become.

We are currently working to develop economic thresholds for three cornered alfalfa hopper (TCAH), but in the mean time, we will rely on experience and best guesses for making treatment decisions. No studies have ever shown a clear relationship between TCAH feeding injury and yield loss in peanut, but we cannot afford to ignore this insect when large populations are present. Pyrethroids are economical and provide good control of TCAH; be aware that these broad-spectrum insecticides will also reduce populations of beneficial insects.

Take a look at this water use curve for peanuts provided by Gary Hawkins, UGA Extension Engineer

Use these charts as an indication of what the peanuts need at different maturity and planting dates.  These charts can also be used as a guide to how much water is needed by peanuts.  If the particular field has received ample water to produce the crop, then irrigation may not be needed.  Also be aware of fact that soil type has an impact on the amount of water available to the crop.  For sandy soils, a high intensity rain will more than likely infiltrate and may provide needed water for crop, however, in heavier soil, the same intensity rainfall will potentially have high losses due to runoff because it will not be able to absorb the water as well as the sandy soil.  On the other hand the heavier soils have a higher water holding capacity and will retain moisture for longer than sandy soils.

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