Georgia peanut harvest timing

IT'S PEANUT DIGGING time in Georgia, and farmers need to make sure the crop in their field reaches peak maturity before harvest.

Timing critical for this year’s Georgia peanut harvest

Digging peanuts at the right time ensures a grower gets the most out of yield potential and quality. Research by scientists with the National Peanut Research Lab show digging three weeks too early can result in a 30 percent reduction in yield potential. Thrips caused more damage to peanuts early this year than in years past, resulting in more reports of the disease tomato spotted wilt virus that they carry.

Georgia’s 2013 peanut harvest got under way the second week in September, a week or so later than usual.

But full throttle will hit later this month. It’s been a tricky, wet year for growers in the state and digging times will be tricky, too.

Digging peanuts at the right time ensures a grower gets the most out of yield potential and quality, John Beasley told farmers, consultants and other attendees at the annual University of Georgia Cotton and Peanut Field Day Sept. 11 in Tifton, Ga.

“Do not assume that any of the 140-145 day maturity cultivars will be ready to dig in 140-145 days. Environmental conditions can cause fields to be ready sooner or later than what is expected. The absolute worst decision a grower can make is to dig based on calendar days and not check the maturity with the Hull-Scrape Maturity Profile chart,” said Beasley, the UGA Extension peanut agronomist.

Local Extension agents conduct hull-scrape profiles and can help growers use this method. Brian Tankersley, UGA Extension director in Tift County in south-central Georgia, says peanuts in his county are running a bit behind the normal average, several days. But he expects by the third and fourth week of September a majority of the peanuts in the county will be dug.

Unusually heavy rains and cloudy weather June through August in that region affected peanut growth. But the weather in the region has cooperated in the last two weeks with plenty of sunshine.

Though there are a lot good looking peanut plants in fields, growers are ready to see what yields hold underground in some fields that were under water or had delayed fungicide applications due to wet weather.

Don’t dig before it’s time

Research by scientists with the National Peanut Research Lab show digging three weeks too early can result in a 30 percent reduction in yield potential.

The Peanut FARM, or Field Agronomic Resource Manager, helps calculates adjusted growing degree days, referred to as aGDD, for the season. Research by the USDA-ARS National Peanut Research Lab determined that peanut maturity was a factor of heat unit accumulation and water.

Much like the DD-60s on cotton, this model works based on daily average temperature minus a base temperature, or 56 in the case of peanuts compared to 60 in cotton, plus the impact of water.

The target is 2,500 aGDDs for peanuts. It’s not too late to use this tool and you can find it here.

Peanut harvest tips for 2013

Though most growers know these tips, Beasley stressed to keep fresh on growers' minds as harvest gets under way:

• Be sure and clean out old debris from peanut combines and trailers, including corn, wheat or old peanuts from previous harvests. This old debris could be a source of Aspergillus flavus mold.

• Have sharp blades on peanut digger-shaker-inverters. Replace worn out blades.

• If you have any field that is two weeks or longer from harvest and it has been two weeks since the last fungicide application, make another application to protect foliage until harvest.

• Level off the top of the peanuts in a drying trailer. Too often producers will have a peak, or mound, of peanuts in the middle of the trailer trying to get more peanuts on the trailer. This results in uneven drying, or curing. The peanuts in the peak will have a higher moisture content than those down along the sides.

• Do not dig too far in advance that would leave acreage susceptible to weather changes before they can be combined.

Check cylinder speed frequently

And check the picking cylinder speed frequently during the day. A cylinder speed that is set too fast can end up shelling peanuts as they are combined. These “loose shelled kernels”, or LSK’s, are a primary source of A. flavus development.

It isn’t uncommon to adjust cylinder speed in a combine two or three times in an afternoon. The cylinder speed may be too slow when starting and there is higher humidity earlier in the day, resulting in poor pod removal from the vines.

If cylinder speed is set faster to adjust for tougher vines, that faster speed may be too fast as you get into the middle or later in the afternoon and vines are more brittle.

Mild insect year, but not clear just yet

“We’ve had a mild insect year with the exception of a very heavy thrips pressure early in the spring. Around June 10 we were on the tail end of a big thrips flight that started mid-May and these thrips found our peanuts. They were young and the thrips really ragged them up,” said Mark Abney, UGA Extension peanut entomologist.

The thrips caused damage but the thrips also carry and transmit tomato spotted wilt virus. There have been more reports of TSWV this year than in recent years in Georgia, likely due to the heavy thrips pressure earlier in the year, Abney said.

Abney said most growers are clear for any remaining problems with insects this year. But growers need to keep an eye on late-planted peanuts. He’s gotten reports of spider mites causing problems in Mississippi and South Carolina.

“They’ve gotten dry and gotten dry quicker than we (in Georgia) did and they are seeing spider mites. Don’t ignore peanut fields as we get into the last few weeks before harvest.

“Because if you got two or three weeks left before you dig and you end up with a heavy spider mite population, those things can take off and go really fast. You can end up with a lot of foliar damage on some peanuts that you need to make some pounds the last few weeks.”


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