. Carnegie Institution of Washington publication. THE BRAZILIAN DISEASE OF MANIHOT. 28l per cent of starch in the dry material as in the normal mandioca, there was scarcely per cent in the diseased mandioca. The observations show that the disease attacks very often the cuttings (mudas) of mandioca, when they are made very long before planting. In this case the tips of the stems begin to rot. As the circulation of the sap occurs even in the cut stems, the conta- gion propagates itself in the bundles. (canaes) without leaving external signs. The slips cut from such stems die for the
. Carnegie Institution of Washington publication. THE BRAZILIAN DISEASE OF MANIHOT. 28l per cent of starch in the dry material as in the normal mandioca, there was scarcely per cent in the diseased mandioca. The observations show that the disease attacks very often the cuttings (mudas) of mandioca, when they are made very long before planting. In this case the tips of the stems begin to rot. As the circulation of the sap occurs even in the cut stems, the conta- gion propagates itself in the bundles. (canaes) without leaving external signs. The slips cut from such stems die for the greater part, and on the other hand, are liable to con- taminate others. The disease is grave, contagious, easily propagated, inoculable, and can be transmitted by insects. If care is not taken it may cause con- siderable injury to the cultivation of this plant of ours, which is of general use. With some cultural precautions the malady may be avoided or les- sened in severity. Curative treatment can not be applied, since the disease is internal, and generalizes itself directly in the plant. The preventive measures which we advise, in order to avoid the pro- pagation of the plague, are as follows: 1. Plant resting shoots (mudas) absolutely not suspected, coming from healthy plantations, rejecting all doubtful stalks. 2. Cut the cuttings (estacas) with the greatest care, without tear- ing or wounding the tissue, in such a manner as to reduce the surface and the possibility of contamination. 3. Do not plant the mandioca in soil infected by preceding diseased plantings, but cultivate other things not subject to contamination by the same bacteria. 4. Plant the cuttings as soon as possible, in order to avoid the contamination which occurs easily during the period of slow growth. 5. Plant resistant varieties: Mandioca parda and Mandioca azul resist better than the Mandioca branca and aipim. The bacteria are found in pure colonies under the bark, in the young swellings. The isolation o
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