| dc.description.abstract | Cowpea rust caused by Urornyces phaseoli
var Vignae is a major factor limiting cowpea
production in Kenya. Epidemiology and control
measure studies were carried out on this disease.
Investigations included studies on symptomatology,
factors affecting uredospor.e germination, disease
development, histopathology, disease progress
in the field, spread and survival of the pathogen,
host range of the fungus, varietal reaction
of the different cowpea cultivars and chemical
control.
Germination of uredospores occurred within
a wide range of temperatures, relative humiditY9
liquid media, and pH. However, the optimum
conditions for germination were when the spores
were mounted in sterile tap water dried and
incubated at 200C and 100 percent relative humidity.
Plant and leaf age affected disease development.
The older the plant and the leaf, the Iess
susceptible it was to cowpea rust. Uredosori
developed within six to eight days after inoculation.
Uredospores formed on the leaf pustules
were spread to higher leaves on the same plant
and to other plants through wind ·and probably by
contact. The pathogen survived only on infected
debris. Besides cowpea, the pathogen attapked
,Phaseolus aureus, MacroRtilium atropurpureum
and Vigna parviflora. Varieties of cowpea
differed significantly in their reaction to
this rust and could therefore, be incorporated
in breeding for disease resistance. Baycor
and bayleton proved to be the best·fungicides
in controlling cowpea rust in laboratory, glasshouse
and in the field. | en |
