|By TIM THORNBERRY
LEXINGTON, Ky. — Kentucky tobacco farmers have seen the first cases of blue mold in recent weeks and growing signs that the disease is beginning to spread.
The first case was detected in the eastern Kentucky’s Magoffin County causing a total loss for the two farmers affected. The disease quickly spread to neighboring Morgan County.
So far the blue mold has been confirmed in several other counties including Adair, Bath, Bourbon, Boyle, Carter, Greenup, Menifee, Mercer, Warren and Wolfe.
Clark County in Central Kentucky was added to the confirmed list on June 28 and unconfirmed cases are reported in Boyd, Harrison, Pendleton, Pulaski and Spencer counties, according to the University of Kentucky’s Tobacco Disease Information page.
In 2005 only 15 counties had confirmed cases of the disease compared to 40 in 2004 but a blue mold outbreak in 1996 cost Kentucky growers an estimated $200 million. The disease was found in 100 counties in 1996.
Preventative measures should be taken now to combat the disease according to Kenny Seebold, UK extension plant pathologist.
“At the moment, I am urging our growers to keep up preventive applications of fungicide to be on the safe side,” he said.
Seebold also said he thought most of this year’s blue mold problems came from plants shipped here from outside the state since the disease doesn’t generally overwinter in Kentucky.
Most of the infections are believed to have occurred when the plants were in float systems prior to being set in fields.
Franklin County Extension Agent Keenan Bishop said the disease has yet to show up in that county but the potential is there.
“It’s getting closer and I think it’s a matter of when and not if,” he said. “It could strike at any time but the farmers here are experienced and know what to look for and how to deal with it.”
Bishop also pointed out that in this time of no price supports every bit of leaf counts.
“The disease has the potential to be a real problem. If we start seeing lost leaf area, that could hurt,” he said.
Burley production dropped to an estimated 143.5 million pounds last year as federal price supports ended. This was a 31 percent drop from 206.7 million pounds in 2004.
Blue mold primarily affects tobacco and is caused by a microorganism called peronospora tabacina and can occur in the plant bed or field. It rapidly produces tiny spores that are ejected into the air and spread by air currents.
According to the website MicroscopyU.com, “in recent years, biologists have begun using meteorological tools to track clouds of these spores traveling on the wind over the Caribbean Sea, Latin America, the continental United States, and Canada. This information is used to predict outbreaks of blue mold, giving tobacco growers an opportunity to protect and treat their crops. Blue mold, however, has proven to be extremely adaptable. New strains of the fungus appear rapidly following release of resistant tobacco varieties and new fungicides.”
Signs of the disease include circular yellow spots, up to one inch in diameter on the leaves. Blue-gray fungal growth is produced on the underside of these spots when the fungus is active. Spots become light brown when the leaf tissue dies.
The disease first develops on lower leaves, but it rapidly spreads to upper leaves during wet, cool weather.
This year’s first reported outbreaks came about one month earlier than normal. Unless weather conditions across the state turn hotter and drier, the disease is expected to expand even more.
This farm news was published in the July 5, 2006 issue of Farm World, serving Indiana, Ohio, Illinois, Kentucky, Michigan and Tennessee.