THIS PAPER reports a survey of the distribution of greening disease in the citrus areas of South Africa and a comparison of the symptoms of infected trees grown under different conditions. Schwarz (3) and Mc-Clean and Oberholzer (2) recently showed that greening disease is caused by an insect transmitted virus.
Materials and MethodsIn the major citrus-growing areas of the Transvaal, the Cape, and Natal, more than 300 sweet orange [Citrus sinensis (L.
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