The furor over Asian soybean rust has subsided somewhat as farmers have turned their attention to other things. So far, the disease has been confirmed in three locations in the continental United States in 2005 — two in central Florida and one in southwest Georgia.
Conventional wisdom says it would take unusual weather to move soybean rust spores from those locations into the Mid-South or the Midwest. Prevailing winds are more likely to carry them across Georgia and into the Carolinas and, possibly, to Virginia.
But those who have seen Monte Miles’ computer modeling of how Hurricane Ivan drew air containing soybean rust spores from over Columbia, carried them across the Gulf of Mexico and into an area from Louisiana to South Carolina know that such patterns are not impossible.
(Asked about the first identification of soybean rust in central Florida in March, the USDA/ARS plant pathologist said he thought the discovery indicated more of a threat to the East Coast than to the Mid-South.)
The weekly soybean rust update map that appears on these pages has not been showing red in Louisiana or Texas, the two areas that could represent a direct threat to the Mid-South and the eastern Midwest. That doesn’t mean soybean rust did not overwinter in Louisiana after it was first discovered there last Nov. 10.
While south Louisiana doesn’t have as much kudzu as Mississippi, Alabama and Georgia, it is home to several varieties of clover, another legume that is an alternate host for soybean rust.
If soybean rust is discovered in south Louisiana or south Mississippi, that will change the dynamics of the soybean rust threat quickly, which raises another issue: Do chemical companies have enough fungicide to deal with a full-blown outbreak of soybean rust?
Experts say companies have enough fungicide on hand to spray 30 million acres of soybeans in 2005. That’s not quite enough to cover half of the U.S. crop with a single application.
EPA has been granting Section 18 emergency exemptions for almost every fungicide with any degree of efficacy because the agency doesn’t want to be blamed for not responding if a major rust outbreak occurs. “I think they’d grant a Section 18 for Coca Cola if they thought it would work on rust,” one crop protection chemical executive said.
There were reports of growers ordering fungicides early on to stockpile them, but companies have been holding back so they can quickly shift supplies to areas of specific outbreaks.
“I think our track record over the last five decades is that rarely have we swung and missed when we’ve been faced with a serious threat,” said Jay Vroom, CropLife America president, whose association represents crop protection chemical manufacturers.
Ideally, rust will infect only 2 million or 3 million acres so soybean farmers, Extension specialists and chemical companies can work out the kinks this year. But you might start slipping a few extra dollars in the collection plate to be on the safe side.