. Citrus fruits; an account of the citrus fruit industry, with special reference to California requirements and practices and similar conditions . er ofthe tree. This is followed by adying back of the young growthwith the formation of smallswellings or gum pockets at thenodes. These often crack openand tears of gum are exudedfrom the very young twigs, whilethe cracks on larger twigs appearfilled with a red or browngummy substance. Often af-fected twigs will attempt a newgrowth but succeed only in form-ing clusters of sickly, palecolored buds in the axils of theleaves. Water sprouts oftenarise
. Citrus fruits; an account of the citrus fruit industry, with special reference to California requirements and practices and similar conditions . er ofthe tree. This is followed by adying back of the young growthwith the formation of smallswellings or gum pockets at thenodes. These often crack openand tears of gum are exudedfrom the very young twigs, whilethe cracks on larger twigs appearfilled with a red or browngummy substance. Often af-fected twigs will attempt a newgrowth but succeed only in form-ing clusters of sickly, palecolored buds in the axils of theleaves. Water sprouts oftenarise from healthy wood belowthe diseased tissue, which in turnmay or may not become fruit on badly affectedbranches either falls or remainssmall and pale yellow in the fruit which reachessome size exhibits a very char-acteristic dark brownish redstain which appears as irregularpatches of gummy material laidover the surface. These red areasare usually slightly elevated, and badly affected fruit oftensplits open longitudinally while hanging on the tree. Affectedfruit is usually abnormally thick skinned, contains numerous. Fig. 130.—Exanthema pustuleson Valencia orange twigs. Diseases and their Control o71 gum pockets at the center, and in tlie case of oranges has aninsipid sweet taste. In many cases exanthema is accom-panied by mottled-leaf, although this is prol)al)ly merely acoincidence, as there is no known connection between the twodiseases. Exanthema is most common on the orange al-though it has been found by the writer on both lemon andpomelo. From all its appearances exanthema would naturally besupposed to be a fungus disease, but this appears not to be thecase. A great deal of scientific investigation has been ex-pended, but as yet no fungus or other parasite has been foundconnected with the trouble. Experiments have shownmoreover that the disease can be produced in healthy plantswithout the aid of any parasite whatever. For these reasonsit is cons
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectcitrusfruits, bookyea
