A SULPHUR‐DEFICIENCY DISEASE OF THE TEA BUSH

Publisher Website
Google Scholar
Abstract
SUMMARY.: The yellows disease of tea, the nature of which has hitherto remained obscure, has caused serious losses to planters in Nyasaland. It is characterised by a progressive degeneration of the bush, in which the leaves become chlorotic, small, uprolled and of stiff texture, and are finally shed. Eventually the bush dies. The disease usually only appears when the soil has been impoverished by erosion or cropping. On certain soil types it may appear in young plantings on newly cleared land. In field experiments the disease was prevented or cured by treatment of the soil (a with mixed fertilisers that included sulphates, (b with the sulphates of ammonium, potassium, sodium or magnesium, or (c with elemental sulphur. Typical symptoms of yellows disease appeared in tea seedlings grown in water culture deprived of sulphur. Individual branches of diseased bushes in the field made normal healthy growth after absorbing through a side shoot a dilute solution of a sulphate. The application of sulphates to certain roots only of a diseased bush caused a recovery only in the branches subtended by those roots. Tobacco plants grown in Nyasaland soil without added sulphur developed a characteristic chlorosis, which was cured by the addition of sulphur. The part played by Kkizoctonia bataticola was studied and it was concluded that this fungus was not concerned in the initiation of the disease. This evidence has led us to conclude that tea yellows disease is produced by a deficit of sulphur in the plant in relation to other essential elements.