Symptoms and Signs
Fig mosaic can cause symptoms on both leaves and fruits. On leaves, mosaic spots are distinctly yellow, contrasting with normal green color of the foliage. The margins of the yellow spots blend gradually from a light yellow color into the dark green of healthy tissue. Mosaic spots or lesions may be uniformly scattered over the surface of the leaves or may appear as irregular patches of light green diffused widely throughout the leaf blade. Later in the season, a rust-colored band develops along the border of the mosaic spots, apparently caused by the death of epidermal or subepidermal cells.
Deformed leaves may occur on the same twig as normal leaves. Mosaic spots on fruits are very similar to those on leaves, but less conspicuous. Premature fruit drop may also occur in certain cultivars. Infected Calimyrna trees seem to produce smaller and fewer fruit.
Comments on the Disease
Black Mission is the most seriously damaged cultivar; Kadota and Calimyrna are the least affected. Ficus palmata, or trees derived from seedlings having F. palmata as the male parent, appear to be immune to mosaic. The fig mosaic is vectored by the eriophyid mite Aceria fici; feeding by a single mite is sufficient to transmit the virus to a healthy seedling of F. carica. The virus can also be transmitted by grafting, but it is not seedborne.
For tree propagation material, choose trees that do not show symptoms of mosaic. Examine propagated young plants carefully for symptoms of mosaic before planting them in the field. Never plant fig cultivars that are propagated from mosaic-infected trees. Controlling fig mites may help reduce incidence of this disease.