The Spread Of Armillaria Mellea (Fr.) Quel. In Tung Orchards

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Wiehe, P. O.
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The fungus Armillaria mellea (Fr.) Quel., is one of the serious pathogens affecting the tung oil tree A leu rites montana in Nyasaland. Death from root rot and decay of the tower portion of the trunk is frequent in certain areas and often results in significant economic losses. Tea which is cultivated in Nyasaland under similar climatic conditions as tung is also susceptible to attacks by this fungus and the host-parasite relationship was studied in detail by Leach (1937, 1940), who was able to demonstrate that a supply of carbohydrates in the tissues is an essential condition for parasitism. Leach further showed that the foci of Armillaria infection in tea gardens were the stumps and root systems of indigenous trees left in the ground after felling. As a result of these investigations he recommended that before establishing tea gardens in virgin woodland areas, indigenous trees should be ring barked, so as to deplete the root systems of their carbohydrate reserves. Since the factors involved are the same, these recommendations are equally applicable in the case of new tung plantations and indeed of any woody crop liable to infection by Armillaria.
East African Agricultural And Forestry Journal, 18, p. 67-72