Bulletin 229, Diseases of Citrus in Florida


nection with various injuries and also with certain diseases at-
tacking twigs and small branches.
 The first symptoms of gummosis are the development of one
 or more slight cracks
 in the bark and the
 oozing out of a pale-
 colored liquid g u m
 which usually runs
 down the bark in
 streak s, forming
 "tears". Later, the
 exuded gum hardens
 and darkens upon ex-
 posure to the air and
 collects in I a r g e
 quantities at the
 cracked places in the
 bark, often becoming
 so abundant as to
 completely obscure
 the cracks in the
 bark (Fig. 25). The
 gumming areas may
 be confined to one
 side of a trunk or
 limb or may extend
 entirely ar o u n d
 them. The gum ex-
 udes in the greatest
 abundance d u r i n g
 the period of active
 growth in the spring
 and early summer
 and frequently ceases
 entirely in the fall
 and winter.
 I f t h e exuded Fig. 24.-Severe case of gummosis on lemon
 masses of gum be cut trunk.
off and the outer, dark part of the bark scraped away over the
gumming portion of the trunk or limb the various stages in the
development of the disease can be seen (Fig. 26). The most re-