Browsing by Author "Nichols, R. F. W."
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Item The Brown Streak Disease of Cassava Distribution, Climatic Effects and Diagnostic Symptoms(1950) Nichols, R. F. W.Brown streak disease of cassava (Manihot utilitarianism Pohl.) was first recorded and described by Storey in a progress report published in 1936[1]. There appear to have been no other published accounts. The Amani work up to 1936 had demonstrated that the disease was perpetuated through vegetative propagation and transmissible through grafting; and in the absence of any visible parasite the causative agent was assumed to be a virus. Later work led to a strong suspicion that a White-Fly (Bemisia sp.), was the vector of the virus in the fie1d[2]; but confirmation or this had not been obtained before the late war interrupted controlled experimental studies of the disease, and it has not been possible, up to the present, to resume them. The information contained in this paper, therefore, 'is based mainly on field observations. A considerable amount of information relative to geographical distribution, climatic effects and symptoms of the disease has accumulated since Storeys original publication and is set out in this paper.Item Long-Term and Short-Term Cassavas(July, 1944) Jameson, J. D.; Oates, C.; Muir, J. C.; Allnutt, T. B.; Nichols, R. F. W.; Department of Agriculture Kawanda, Kampala ,Uganda, Department of Agriculture Kenya, Department of Agriculture Tanganyika Territory, Department of Agriculture Zanzibar, Cassava Investigation of AmaniIt has been suggested here that correspondents to your journal might be able to throw light on a curious disparity in the practice of cassava cultivation between the various East African territories. In those parts of Uganda where cassava is an important reserve against famine it is the custom to plant up the greater part of the acreage with so-called "long-term" varieties. This description is perhaps not sufficiently definitive, but by it is meant varieties which stay in the ground for two or more years without appreciable deterioration to the tubers. The advantages of this course are presumablyItem Virus Diseases of East African Plants VII-A Field Experiment in the Transmission of Cassava Mosaic(1938) Storey, H.H.; Nichols, R. F. W.; East African Agricultural Research StationGeneral field observations indicate there may be seasonal differences in the rate of spread of the mosaic disease or cassava. It may be surmised that the age of the plant at the time that it becomes exposed to infection may influence its susceptibility. This paper describes an experiment in which these two points been tested.
