Jason Jenkins
Senior Information Specialist
573-882-2980
JenkinsJL@missouri.edu
March 4, 2005
Soybean rust overwinters in Florida;
spore movement forecasting begins
"My opinion is that there’s little risk for Missouri at this time because weather conditions are not favorable for rust, even if there was viable plant material to sustain infection," said Pat Guinan, of the MU Commercial Agriculture program.
Soybean rust was detected Feb. 23 in Dade City, Fla., on kudzu foliage, an alternative-host plant. It represents the first confirmed rust sample found in the continental United States in 2005.
The yield-reducing foliar disease first reached the continental United States in November - most likely on the winds of Hurricane Ivan " and was discovered in a soybean plot in Louisiana. Overall, it has been detected in nine states, including Missouri. When left untreated, rust has caused up to 80 percent yield loss in infected soybean fields in South America. At least 31 legumes may serve as host species for the disease.
Guinan said that in Missouri, prevailing winds during March are generally from the west and southwest. "Then, as the growing season begins, winds will predominantly come out of the south from April through October," he said. "That’s when soybean farmers will want to pay very close attention to what’s going on to the south."
In order for soybean rust to proliferate, living host material must be present, temperatures must be suitable, and moisture must be present.
"A new MU Extension guide on soybean rust says that rust favors temperatures of 46 to 82 degrees with moist conditions. Based on 30-year temperature and precipitation averages in Missouri, that favorable scenario usually occurs the latter half of May and the first few weeks of June," Guinan said.
He added that frost still is likely across all of Missouri. "The average date of the last spring frost is April 5 in the extreme southeastern corner of Missouri and runs until April 20 in our most northern counties," Guinan said. "Temperatures are forecasted to remain below average through mid-March, so as long as host plant material isn’t available, rust spores don’t have anywhere to survive."
Guinan advised producers to keep an eye on developments to the south. The North American Plant Disease Forecast Center at North Carolina State University, http://www.ces.ncsu.edu/depts/pp/soybeanrust/, provides forecasted trajectories of known rust discoveries three times a week through October.
The MU Plant Diagnostic Clinic, 23 Mumford Hall, Columbia, MO, 65211, has developed a procedure for submitting samples for soybean rust identification. Forms and detailed collection and sample submission information are available on the clinic’s Web site at http://agebb.missouri.edu/pdc/.
The new MU Extension guide about Asian soybean rust provides detailed descriptions and photographs of soybean rust, compares it to other foliar diseases found in Missouri, and outlines management strategies. The guide can be found online at http://muextension.missouri.edu/explore/agguides/crops/g04442.htm.
Source: Pat Guinan (573) 882-5908
| Return to Current News Releases | |
|
College of Agriculture Food and Natural Resources
AgEBB |