Any hopes that the U.S. tobacco crop might escape serious damage from tomato spotted wilt were dashed at the end of May and in early June when substantial infestations broke out in Georgia and the Carolinas.
Jerry Breland of the Walterboro area of South Carolina was one of the farmers reeling from the intensity of the hit his flue-cured had taken from the disease. He talked to Southeast Farm Press on June 9.
“I have never seen it this bad,” he said. “There are places around me that have 60 to 70 percent of the plants infected.”
The damage was almost entirely on the early-planted part of his crop, and he had hopes his later plantings would be spared. There was also hope the uninfected plants in infected fields might be able to compensate to some degree for yield loss, by taking advantage of unused fertilizer and also getting more sunlight.
“But sometimes you see seven or eight plants in a row that have died,” said Breland. “It is hard to see how the remaining plants could compensate for that.”
If things got no worse, he expected a 20 percent loss in his production due to spotted wilt on his farm.
“But I am really concerned with the spotted wilt because there seems to be more everyday, or maybe it’s just expressing itself more as the tobacco grows.”
In northeast South Carolina, Ben Teal of Patrick said his fields had about seven to 10 percent spotted wilt infestation. “It’s a problem for us but for some tobacco farmers, 10 percent would look pretty good right now.”
Big problem in Georgia
Breland farms near the state boundary with Georgia, which had perhaps the worst infestation of spotted wilt in tobacco in early June.
"It doubled its infestation rate to around 20 percent of plants showing symptoms (in the week ending June 2), and we have older tobacco in which the infestation is as much as 50 percent,” said J. Michael Moore, the state tobacco specialist for Georgia and Florida. “The symptoms run from dead plants to ones where one or two leaves on one side are dying."
There is no mystery why this happened: Spotted wilt is spread by thrips, and the mild winter weather of 2016-17 allowed for survival and high populations of the insect.
It struck in all the flue-cured-producing states. Besides South Carolina and Georgia-Florida, the incidence appeared headed toward a record in North Carolina, said Matthew Vann, North Carolina Extension state tobacco specialist. "We have suffered losses ranging from five percent to 40 percent.”
In New Bern, N.C., an Extension tobacco agent said infestations had not started a downward trend as of June 6.
“It appears that earlier transplanted fields have the highest incidence with a range of 20 percent to 40 percent,” said Mike Carroll of Craven County. “It appears that just about every tobacco farmer has at least one farm with infestations within the higher range.”
But the overall rate was about 18 percent in that area, which is part of North Carolina’s Coastal Plain.
Most in Coastal Plain
The damage in North Carolina was in fact entirely in the Coastal Plain. Through June 1, there were no reports of spotted wilt in the Piedmont of North Carolina. But there had been a little in the Virginia Piedmont.
"There's not much, but it is more than we are used to," said David Reed, Virginia tobacco specialist. "It is rarely a problem here." At this point, he doesn't expect to see many fields in the Old Dominion this year with more than four per cent spotted wilt infestation.
Spotted wilt is rarely a problem in the burley- and dark-producing states of Kentucky and Tennessee and had not been seen in either type through the first week of June.
Unfortunately, growers in all states were largely stuck with the amount of the disease they had in early June, since control options after planting are largely non-existent.
"There is just so much you can do about spotted wilt, and most of it has to be done by the time the crop reaches this stage,” said Moore. “Once the tobacco is in the field, most measures are futile."
But good sucker control may help, he said.
There has definitely been some loss of potential production, but it is difficult to predict, since as Breland said, tobacco has some ability to recover from spotted wilt damage.
Flea beetles in burley
Though burley states escaped spotted wilt damage, the transplanting season had been very rainy, causing other problems.
• Heavy rains close to the time of transplanting had led to problems with flea beetles. In Macon County, Tenn., the largest burley-producing county in the country, Extension tobacco agent Keith Allen said at the end of May, "We put a control chemical in the setter water to control flea beetles. But in many cases, it was too damp at that time for the plant to take the chemical up."
• The rain-extended transplanting season was setting the stage for diseases in the greenhouse. There were still a lot of plants in houses, and the longer the plants stayed in the greenhouse the more chance there was for disease, said Allen.