Progress in the diagnosis and cure of mineral deficiencies in Cherries

Thompson, S.G.; Roberts, W.O.

Rep. E. Malling Res. Sta., 1945. 60-63


Accession: 013472920

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Experimental evidence indicated that a winter (February) spray of (say) 5 per cent. manganese sulfate gives better control of manganese deficiency of cherries in the current season than does a summer spray, but the effect is no longer apparent after one year. A second experiment concerned cherries with multiple deficiencies. The foliage was a dull yellow with no pattern, and no scorching or necrosis. Analysis of leaf material indicated that iron, manganese, and zinc were low, calcium high, and potash and phosphorus normal. A branch injected with solid iron sulfate in June, 1944, still showed improvement in the early summer of 1945, as did manganese-and zinc-injected branches, though one injected with boron made no progress. Leaves from branches injected with iron, manganese, and zinc all showed chlorosis, which differed with the treatments. A branch injected with iron plus manganese had foliage of a better colour than that produced by either element alone, but a slight deficiency pattern was present. A branch injected with iron, manganese, zinc, and boron in 1944 showed striking improvement, with no sign of chlorosis and a full crop, whereas the rest of the tree was still very chlorotic. New growth occurred in 1945 on the branches injected with iron, manganese, zinc, and boron together, iron and manganese, and iron alone, while no growth followed manganese only. The view was taken that iron was the main deficiency, manganese secondary, and zinc a minor deficiency. A series of trees was, accordingly, given whole tree injections of iron, manganese, and both together, while two other series received dormant sprays of iron and manganese. So far, the injections of iron plus manganese have given the best results, both iron and manganese alone have given great improvement, iron sprays have resulted in some improvement, and the manganese sprays appear to have had no effect. It is pointed out that diagnosis by leaf symptoms alone may lead to serious errors in cases of complex deficiencies and other means of diagnosis are desirable under these circumstances.