College of Agriculture, Forestry and Life Sciences; Public Service and Agriculture

Price swings and new disease put strain on S.C. cotton growers


SANTEE – One thing many farmers know for certain is that nothing is certain right now.

Cotton is planted in South Carolina the first week in May.
Cotton is planted in South Carolina the first week in May.

During the South Carolina Cotton Growers Meeting held here recently, Clemson Extension economist Nathan Smith told growers that despite stable demand for cotton worldwide, fluctuations in yields, prices and international trade have the potential to create stress for both producers and users.

“United States’ exports are projected to increase,” Smith said. “Even with more exports, however, we could see an increase in U.S. stocks due to higher production in 2019.”

Higher production and ending stocks going into 2020 for the United States led economists to forecast a season-average price of 63 cents per pound, Smith said.

While U.S. exports to China have decreased, markets in Bangladesh, Vietnam, Pakistan and Turkey have grown. But Brazil’s market share also has increased, further depressing cotton prices in the U.S. Reports show cotton prices will be volatile depending on acreage reports, crop conditions and weather.

“Right now, we don’t know where prices are going to go,” Smith said. “As they stand right now, we need good yields or help in the markets to cover costs. Our expectations for 2020 in S.C. are that cotton acreage will remain the same or be down a little.”

Almost 14 million acres of cotton were planted in the United States in 2019. This was down about 2.7 percent from 2018. Some economists predict cotton acreage may drop several million acres in 2020. Reduced acreage could raise prices.

Clemson University cotton specialist Michael Jones said South Carolina cotton growers grew a good quality crop in 2019. To continue this trend in 2020, Jones said growers need to do their homework when it comes to variety selection.

“We had a good quality crop last year,” Jones said. “Lint yield was above average and fiber quality was excellent. To continue to have good crops, growers will need to study and determine which variety or varieties will work best for them.”

Variety selection criteria include: yield potential, yield stability, fiber quality, value-added traits, plant maturity, nematode resistance, stormproof ability, lint percentage and leaf hairiness. DP1646B2XF is one variety that has been popular with farmers in the Cotton Belt North Carolina, South Carolina, Georgia, Alabama, Mississippi, Arkansas, Louisiana, eastern Texas and Southern Oklahoma.

While cotton quality may be high, cotton acreage is forecast to drop 25% in South Carolina in 2020. The latest USDA figures show 300,000 acres were planted in cotton in South Carolina in 2019. Projected cotton acres for 2020 in the state are 224,167.

In addition to prices and variety selection, cotton growers also were made aware of a new cotton disease. According to John Mueller, Clemson cotton pathologist, cotton growers need to be on the lookout for cotton blue disease. This disease is caused by the cotton leafroll dwarf virus, transmitted by cotton aphids. It first appeared in the United States in 2017 and was detected in 10 counties in South Carolina in 2019.

Symptoms include:

  • Drooping leaves that vary from red to dark green.
  • Crinkled or rugose leaves
  • Stunted plants that suffer fruit deformation and fruit shed, or are all together barren.
  • Late season symptoms include stacking of the internodes with copious fruiting, but consequent rapid fruit abortion.
  • Elongated main stems.

Mueller said there are no fungicides or antibiotics to control the virus.

As for controlling cotton aphids that transmit the disease, Clemson entomologist Jeremy Greene said the use of insecticides will not prevent the virus from establishing in fields.

“We think, and evidence so far has shown, that we cannot keep infected aphids from infecting plants in a given field.  We are conducting more research to see if spread of the virus can be slowed some in a given area, but that might not be possible,” Green said. “We can greatly reduce numbers of aphids in cotton with insecticides, but we cannot eliminate aphids from cotton and probably will not prevent transmission of the cotton leafroll dwarf virus.”

Greene said insecticides can reduce plant stress associated with aphid feeding. Control of cotton aphids with insecticides varies by location.

Low, but detectable levels of aphids were found in South Carolina in 2019. Research on control of cotton aphid and the virus is ongoing in South Carolina.

In addition to South Carolina, cotton leafroll dwarf virus also has been detected in Alabama, Florida, Georgia, Mississippi and Texas.

About 80% of the South Carolina cotton crop is planted the first week in May. Cotton harvest begins in late September.

Tripp Plummer is an Orangeburg County farmer who attends the South Carolina Cotton Growers’ Meeting every year. In addition to cotton, he grows corn, soybeans and wheat.

“This meeting is convenient for us,” Plummer said. “We get valuable information by attending the meeting and, then, we are able to do the dicamba training that is required for our license. We can do it all in one day.”

Dicamba is a common herbicide used to kill broadleaf weeds. Federal label changes require farmers and pesticide applicators who use dicamba-based products to receive training as required by the Environmental Protection Agency.





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