New Corn Disease Detected in the Midwest
Posted by feww on September 24, 2015
Tar spot, a corn disease new to the U.S., reported in Indiana, Illinois
“Tar Spot,” a new disease affecting corn crops, has been confirmed in DeKalb, LaSalle and Bureau counties in Illinois, agriculture officials said.
The disease, not previously reported in the United States, was also identified in Indiana about two weeks ago after samples submitted from an Indiana field in the Cass/Carroll county area were diagnosed at the Purdue Plant and Pest Diagnostic Lab (PPDL) confirming the presence of Phyllachora maydis fungus, said a report.
“There are actually two fungi that cause tar spot disease on corn: Phyllachora maydis and Monographella maydis,” said University of Illinois Plant Clinic director Suzanne Bissonnette. “While Monographella maydis is known to be able to cause economic yield losses in Latin America, Phyllachora maydis is not known to significantly reduce yield. Other pathogens may be confused with tar spot, especially the overwintering teliospore or black phase of corn rust. Also, there are many fungi, called saprophytes that feed on dead corn tissue and form black splotches on the leaves.”
So far, only Phyllachora maydis, has been detected in Indiana and Illinois.
To date, cases of tar spot have been detected in at least four locations in Indiana and three in Illinois, The U.S. Department of Agriculture (USDA) has confirmed.
Symptoms and signs of tar spot include brown lesions and black fungal structures. Lesions can cause large blighted areas of tissue. Source: Pest & Crop Newsletter/ Purdue Cooperative Extension Service/ Purdue University.
The disease was previously found in cool humid areas at high elevations in Latin America including Mexico, Central and South America.
“It looks like it came up out of that area,” said Bill Dolezal, a research fellow for seed company DuPont Pioneer, according to a report.
“Tropical Storm Bill, which brought rain to the central United States in June after spinning through the Gulf of Mexico, may have transported the disease,” Dolezal believes.
In 2004, an active hurricane season is thought to have brought a soybean disease called Asian soybean rust into the United States from South America for the first time.
Recently, farm animals have suffered more than crops from new diseases entering the country from abroad. This year, the United States suffered its worst animal-disease emergency ever in poultry from a strain of bird flu that originated in Asia.
In 2013, a pig virus never before seen in the United States was found. Previously seen in Europe and Asia, it has since killed millions of baby piglets. It’s still unclear exactly how the virus arrived. [See report]
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