In the last few weeks, several samples have been submitted to the Auburn University Plant Diagnostic Lab where fig rust has been found. This is an earlier detection of the disease than normally occurs. The disease is presenting itself while figs are being picked, which may present some problems.
Fig rust is caused by the fungus Cerotelium fici and is one of the more common fig diseases in the southeastern United States. Symptoms of this disease begin as small, yellowish spots on the upper surface of the leaves. As these spots grow larger, they turn reddish-brown in color. On the lower surface of the leaf, the lesions have a blister-like appearance.
Heavily infected leaves turn yellow or brown, particularly around the edges (resembling leaf scorch), and drop prematurely. Trees with the disease can defoliate within a few weeks. While the disease only affects the leaves, this premature leaf drop can cause fruit to scorch without the protection from foliage.
No fungicides are registered for use on edible figs. Management of fig rust relies solely on the use of cultural practices. Rake up and destroy (burn or trash) fallen leaves to reduce inoculum levels. Selectively prune branches to increase airflow through the canopy to promote rapid drying of the foliage. Fertilize and irrigate accordingly.
Featured image from Elizabeth Bush, Virginia Polytechnic Institute and State University, Bugwood.org