The disease was confirmed on Aug. 20 on samples from a residential lime tree in Algiers in Orleans Parish, said LSU AgCenter plant pathologist Don Ferrin.
“We don’t want to cause undue alarm, but we do want people to be aware of it,” Ferrin said. “It was a pretty good year for scab to develop on unsprayed trees, and it would be quite noticeable if it’s present “
Fruits are only susceptible for the first six to eight weeks of their development, so they need to be protected then. For homeowners, the only fungicides readily available are copper-based fungicides, he said.
Sweet orange scab occurs primarily on sweet oranges, tangerines and satsumas, but it also can occur on other types of citrus trees.
The scab presents little problem, Ferrin said, because it’s mostly cosmetic, but it affects the ability to sell infected fruit for the fresh market. “When severe disease develops early in fruit formation, it can prevent their normal development.”
“If you find scab on citrus, contact your LSU AgCenter parish office,” Ferrin said.