. Fig. 70.—Full-grown walnuts ruined by blight. Chlorosis.—The foliage of affected trees is of a bright-yellow color and the growth more or less stunted and deformed. Typical chlorosis is caused in trees of many kinds by the presence in the soil of excessive amounts of lime, which prevents the normal functioning of iron in the tree. The walnut is a lime-loving plant, but in some districts where the lime content of the soil is very great, the foliage of walnut trees shows the same yellow color as that of pears and other species. For treatment see page 135. Crown Gall.—The walnut, including all
. Fig. 70.—Full-grown walnuts ruined by blight. Chlorosis.—The foliage of affected trees is of a bright-yellow color and the growth more or less stunted and deformed. Typical chlorosis is caused in trees of many kinds by the presence in the soil of excessive amounts of lime, which prevents the normal functioning of iron in the tree. The walnut is a lime-loving plant, but in some districts where the lime content of the soil is very great, the foliage of walnut trees shows the same yellow color as that of pears and other species. For treatment see page 135. Crown Gall.—The walnut, including all the species used for root- stocks is rather susceptible to this common bacterial disease, caused by Phytomonas tumefaciens. Large rough swellings develop on the roots, at the crown, and at places higher up on the tree, esi")ecially at the point of grafting on top-worked trees. Rough, slow-healhig graft unions and points of injury are most likely to become infected.
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Keywords: ., bookc, bookcentury1900, bookcollectionamericana, booksubjectfruit
