Citrus Scab is characterized by a large number of small raised marks or scab on the fruit of citrus trees. The leaves can also show similar brown scale- and scab- like lesions. In cases of significant infection, the fruit will not develop normally and the tree will undergo early leaf drop. The scab is caused by a fungus that attacks the surfaces of the fruit and leaves. It is encouraged by damp conditions caused by a wet spring period or the use of over-head irrigation and sprinklers.
To control citrus scab, spray the tree with Captan Fungicide. The Captan fungicide should be applied in the late winter before the new spring growth starts and a second spray application should be applied shortly after the petals have dropped from the fruit blossoms. To help reduce the spread and growth of Citrus Scab never use a water sprinkler on a citrus tree. When watering a citrus tree, always use a soaker (or drip) hose on the ground near the tree’s dripline.