Studies on diseases of cassava and yam in Trinidad
1988
Rajnauth, G. (Ministry of Food Production, Marine Exploitation, Forestry and the Environment, Centeno (Trinidad and Tobago). Central Exp. Stat. Dept. of Plant Pathology) | Pegus, J.E.
Aetiological studies confirm that a bacterial disease of cassava (Manihot esculenta, Crantz), first observed in 1976, was due to Xanthomonas campestris pv manihotis (Berthet and Bondar) Dye, the causal agent of cassava bacterial blight (CBB). Field surveys in 1977 in the northern counties of Trinidad indicated that CBB was only present in the Centeno-Carapo area but other diseases, some previously unreported, were present: brown leaf spot, white leaf spot, blight leaf spot, cassava rust and cassava ash. Continuing surveys have indicated that CBB can now be observed in many parts of the island and is a severe production constraint in some areas. In addition, a new disease was observed, namely root small pox disease. Field surveys of yams (Dioscorea alata L.) during 1985-1986 indicated that the major disease of this crop is anthracnose caused by the fungus Colletotrichum gloesporioides Penz. This disease has proven to be very severe on white Lisbon, the dominant commercially grown cultivar in the main yam growing areas of south Trinidad resulting in heavy losses and abandonment of fields. In fungicide trials at El Carmen Field Station, evidence of symptomatic control as reflected by the level of leaf spotting and leaf blighting was observed in benomyl sprayed plots and to a lesser extent, in captafol and mancoseb sprayed plots
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