Title: Cirtus fruits under irragation
Identifier: cirtusfruitsunde00scra (find matches)
Year: 1914 (1910s)
Authors:
Subjects: Citrus fruits; Fruit-culture
Publisher: Scranton : International Textbook Co.
Contributing Library: Penn State University
Digitizing Sponsor: Lyrasis Members and Sloan Foundation

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32 OliKU^ TKUlih UlNiJl^K IKKlLrAllUlN §25 8ZO /~\Trr\T^ TT/-A â T-rrr\r\ t t â¢Â» t t-^ t-% â ?-» -r-t-» t-»-r <"« 4 »-»^-r<-N'*' \^lli\UD riS.UilC^ UlMJU/i^ ii^i^lLj/VliUlN 66 and usually appear at the side of the tree, or encircling it. At times, however, they come up at a distance from the tree where a root comes near the surface of the ground. The toadstools produce spores which are often so abundant that they cover the ground as a white powder. In addition to the toadstools, felty white growths spread out fanlike within the bark of affected trees. These growths crowd into the healthy bark, which puffs up, becomes moist, and often gummy. A white rot of the wood soon follows; this is accompanied by a clean mushroom odor. The fungus spreads from one place to another by black, cord-like strands about j^ inch in diameter. These are known scientifically as rhizomorphs. Occasionally they fork, but they do not branch like roots. These strands attain enormous length. They may course upwards and downwards in the affected tree, generally under the bark or merely in close contact with the outer surface. They also grow through the soil to con- siderable distance and thus serve to spread the disease from one tree to another. From a small infected area in a grove the disease may spread for several years until quite a large area is affected. Frequently several affected areas in a grove overlap, and if growth is allowed to continue, the entire grove may be affected. 39. Control measures in an affected area consist in blasting out old roots and burning them and then planting some annual crop. After a period of years trees may again be planted, but there will usually be danger of the fungus being in the soil and affecting the new trees. The margin of an affected area should receive treatment to prevent the spread of the disease. A plan suggested by Professor Home is to uproot a number of healthy trees in the zone of advancing infection in the hope of removing enough roots to prevent the fungus from passing through the soil. This work should be done thoroughly and all large roots removed from the cleared strip. Professor Home reports further that he has been trying some experiments in endeavoring to isolate the affected trees by digging a trench around the trees deeper than the roots penetrate, lining the side of this trench with tarred paper, and then refilling the trench in order that cultivation and irrigation can proceed as usual. The theory is that the paper will prevent the healthy roots from passing into the infected area. The success of this treatment is not yet assured on account of the short length of time it has been tried, but it is certainly worthy of trial. Fig. 32 shows the toadstools of fungus root rot. 40. Maldlgoma.âMaldigoma, or foot rot, is a disease that is rarely found in California, but it is very common in Florida. It is characterized by a decay of the bark at the
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Fig. 32 surface of the ground and the exudation of gum on the trunk just above the soil. The bark and finally the wood becomes rotten and dead and a disagreeable, fetid odor is present. Although the dead areas spread in all directions, they spread most rapidly down the main crown roots and around the trunk near the ground. Leaves on affected trees become yellow, the twigs and young branches die, and the tree puts forth a heavy crop of fruit. The entire tree assimies a very unthrifty appearance. The disease is generally found on trees growing on wet, heavy soils where too much water is allowed to stand about

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