Not all citrus disease concerns center around huanglongbing (HLB). While HLB disease garners much of the headlines because of its devastation to Florida’s citrus crop, growers in the cold-hardy citrus region should be mindful of other diseases that can devastate a crop if left untreated.
Jonathan Oliver, University of Georgia (UGA) assistant professor and small fruits pathologist, highlighted some of those disease concerns at a recent citrus grower meeting in Valdosta, Georgia.
“A couple of years back, citrus canker was identified in Georgia, so that’s still out there. I have no recent findings of canker, but that is a disease of concern,” Oliver said. “We have a lot of young trees in Georgia, and citrus is vulnerable to things like root rot and phytophthora. And once trees have fruit, there’s various things like scab and other diseases that can cause issues. Generally, from a disease standpoint, most of those can be managed pretty effectively.”
Citrus canker disease is easily spread by air or water. According to the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS), symptoms can appear on the fruit, leaves and twigs of the trees. Small, round blister-like lesions with water-soaked margins and yellow halos can appear on both sides of a leaf. Heavy infections will often lead to defoliation. Fruit drop can also occur.
According to UF/IFAS, root rot happens when the cortex of fibrous roots becomes infected, softens and appears water soaked. Growers manage phytophthora-induced diseases by integrating cultural practices such as planting tolerant rootstocks and implementing proper irrigation practices.
“As longs as phytophthora doesn’t kill the tree at a young age, it can survive for a while, and there are treatments for that,” Oliver said. “Those diseases are less of a concern, but they are issues for sure that, especially in young groves, growers may need to be a little bit more concerned about.”
By Clint Thompson