Bulletin 229, Diseases of Citrus in Florida


very young and, with their maturity, irregular, raised scabby
or wart-like lesions are formed.
 On the Leaves:-The disease starts as small, pale orange,
 usually somewhat circular, elevated spots. As the leaves develop,
 these infections become well-defined warts or excrescences on
 one side of the leaf, often with a conical depression on the op-
 posite side. The lesions occur on either surface of the leaf but
 most commonly on the under side. The lesions may not be
 visible on the opposite side of the leaf or may penetrate it. They
 may be single or
 irregularly
 grouped. The
 crests of these
 wart-like growths
 usually become
 covered with a
 scabby, corky tis-
 sue, at first pale
 yellowish orange
 in color, later be-
 coming pink,
 then drab and,
 finally, dark olive
 drab as the leaf
 matures and
 hardens. The in-
 fected spots often
 run together and
 cover large areas
 with a corky,
 scabby growth.
 B a d 1 y infected
 leaves become
 very much crin-
 k I e d, distorted, Fig. 8.-Scab on leaves and twig of sour orange.
 and stunted, hav-
 ing very little resemblance to normal foliage (Fig. 8).
 On the Twigs, the characteristic effects of the scab disease
are the development of small masses of similar corky outgrowths
on their surfaces. The centers of infection may remain entirely
separate or may run together to form larger, somewhat elevated