Southern corn rust found in South Carolina
BLACKVILLE — Southern corn rust has been found in South Carolina and growers are advised to spray fungicides to protect yields.
“And we found it Tuesday in a field between the towns of Perry and Salley on Highway 39,” Gunter said.
Southern corn rust is caused by the fungus Puccina polysora. Wind carries rust spores from field to field. Gunter said he believes the fungus, which just infects corn, will spread. He advises growers to spray their fields to reduce spread of the disease.
“It will most definitely drift north during wind events such as the afternoon storms we’ve been having,” Gunter said. “Growers can spray a combination fungicide that will not only protect the crop, but cure any infection that has already started.”
Gunter advises growers to spray irrigated fields.
“If a grower’s corn is irrigated and has good yield potential, then I would spray to protect that yield,” Gunter said. “There are some exceptions, but many of the dry land fields have been hurt by the last couple of weeks of hot, dry weather. Parts of the Pee Dee have and maybe a few other locations could have good yield potential in dry land fields if the fields have real good soils and get timely showers over the same two weeks.”
Justin Ballew, a horticulture and agronomy agent in the Clemson Extension Service Marion County office, said strobilurin products are recommended for preventative treatments.
“But if rust is found in a field, a combination strobilurin and triazole will be better at slowing it down,” Ballew wrote in his blog, Pee Dee Ag News.
Ballew also notes that if corn has been treated within the last two-three weeks, there’s a good chance it will need to be sprayed again. According to Ballew, the oldest corn is “…just starting to show its milk line, so growers definitely aren’t in the clear yet. If growers had just sprayed and were close to 50 percent milk line, then they probably would be OK for the remainder of the season,” he wrote.
Ballew also suggests that growers in the Pee Dee region wait another week to spray if they can because it will take the rust a week or two to move across the state.
Symptoms of southern corn rust are orange to brown masses of spores that can be seen on the upper leaf surface. The rust may infect leaves, stalks and corn husks.