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| Blue mold: Tobacco headache gets early 2008 start in Florida |
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By TIM THORNBERRY
Kentucky Correspondent KNOXVILLE, TN. — With uncertain prices, higher production costs and soggy fields, tobacco farmers in Tennessee and Kentucky have enough to worry about as a new growing season approaches. The last thing they need is to start the season under the threat of blue mold – but that seems to be the way things are shaping up.
University of Tennessee extension plant pathologist Steve Bost said the disease is off to an early start with its discovery in a northern Florida plant bed on March 12, and with it being found at this stage of the season, it could be disastrous for growers. Several weather systems have occurred since then that may have transported spores to the Tennessee area, putting farmers on the lookout for infected plant beds.
“Entire beds could be lost,” said Bost. “If infected plants are set in the field, it could mean an entire season of battling the disease – a battle made more difficult by the fact that one of the fungicides needed for effective control is in low supply.
“Happening so early allows (the disease) to build up a large spore load going into the season and could put us in a difficult spot.”
That crucial fungicide is Dithane DF, which doesn’t build up as much of a resistance to the disease as some other fungicides. Dithane DF is the only Mancozeb product labeled for use on tobacco, said Bost.
He also noted it is difficult to tell what could happen. If the weather turns warm and dry, those conditions could stop the spread of the disease – and farmers in the South know how quickly warm and dry weather can happen. Much of the deeper South is still considered to be in a drought situation.
Bost recommends producers, at this point, check their plant beds every day, begin protective fungicides labeled for this use once a week if the seedlings have dime-sized or larger leaves and stay away from plants grown in Florida or southern Georgia. Going into the summer, he also recommends farmers get their fungicides now, as opposed to later.
Bost’s counterpart at the University of Kentucky College of Agriculture, Kenny Seebold, said some of the worst epidemics of blue mold in Kentucky were associated with early arrival of the disease during production of transplants.
“There’s no imminent threat to producers in Kentucky at the moment, since we’re not too far along in the transplant production cycle, and recent weather patterns haven’t necessarily threatened us,” he said. “On the other hand, it’s extremely important now to keep Southern-grown transplants out of our state if at all possible.”
Bost warns that any field is susceptible to the disease because it can come in on what are known as spore showers. Low-lying fields or those bordered by trees are usually first to get it because of the microclimate, or the way the conditions are in that field. The humidity generally is higher in those areas and tends to stay wetter after a moisture event than those fields with better air drainage.
One thing that may benefit farmers in their fight against blue mold is the possibility of planting a burley variety that is more resistant to it; some are out there, according to Bost.
Also, there seems to be a trend for some burley production to give way to dark tobacco, which is inherently less subject to blue mold. But, before making the switch based solely on worries about the disease, it is wise for producers to remember that dark tobacco is more apt to be affected by black shank, the main disease that inhibits tobacco production.
According to North American Plant Disease Forecast Center, the 2007 blue mold epidemic was mild and started in an unusual place – the first report of the disease came late and was reported in Fayette County, Ky. In past years, first reports have generally come from Florida and southern portions of Georgia.
Last year’s drought no doubt played a part in keeping the instances of the disease low. The center also reported the Cuban crop experienced a significant problem with blue mold during its recent growing season.
This farm news was published in the April 9, 2008 issue of the Farm World, serving Indiana, Ohio, Illinois, Kentucky, Michigan and Tennessee. |
| 4/9/2008 |
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