Dynamics of development of late blight [Phytophthora infestans] in potato, and comparative resistance of cultivars in the highland tropics

Host resistance is an important component for the management of late blight [Phytophthora infestans] on
potato, in the highland tropics, where effective fungicide use is limited because of the cost of application. Potato
cultivars with major resistance genes to late blight (population A) and minor or quantitative resistance genes to the
disease (population B) were evaluated in field studies at two locations in Kenya during 2000, 2001, and 2002 cropping

Dynamics of potato late blight on tubers and farmers' management of the disease in Kenya highlands.

From 1998 to 2001, field experiments were conducted in New York, USA, and Kenya to study the relationship between foliage late blight control and tuber infection in the control of tuber blight (Phytophthora infestans). Most of the tuber infection occurs as a result of inoculum produced on the foliage being washed down into the soil to infect tubers. Tuber resistance and depth, precipitation and soil temperature were important factors, whereas different foliar fungicide applications had no significant effect on overall tuber blight incidence.

Evaluation of advanced R-gene free potato genotypes for late blight resistance, yield, cooking and processing qualities

Late blight (Phytophthora infestans) is a major constraint to potato production
in the tropical highlands of Kenya causing significant yield losses of 30 - 75% in
highland tropics of Kenya. Farmers rely on fungicide application to manage the
disease. However, control is often inadequate due to limited fungicide applications
and use of cultivars with low to moderate resistance to late blight. Use of resistant
cultivars is viewed to be more sustainable both economically and environmentally.

Validation of tuber blight (Phytophthora infestans) prediction model

Potato tuber blight caused by Phytophthora infestans accounts for significant losses of tubers in storage. Despite research on infection and management of tuber blight, there is paucity of information on the prediction of the occurrence tuber blight or modelling of tuber infection by P. infestans under field conditions. A tuber blight prediction model was developed in New York in experiments conducted using cultivars Allegany, NY101, and Katahdin in 1998 and 1999.

Inheritance and selection for resistance to Angular Leaf Spot (Phaeoisariopsis Griseola (SACC)and common bacterial blight (Xanthomonas Campestris pv Phaseoli) in yellow beans

Angular leaf spot (Phaeoisariopsis griseo/a) and common bacterial blight (Xanthomonas
campestris pv phaseo/i) are two major diseases of common bean (Phaseo/us vulgaris
L.). In Africa, the two diseases account for losses of 604,600 tons per year. High levels
of cultivar resistance to the two diseases would minimise yield losses, reduce
production costs and facilitate the production and distribution of pathogen-free seed.
The objectives of this study were; 1) To determine the inheritance of resistance to

Occurrence of Fusarium Head Blight–causing Pathogens and Mycotoxins in Kenyan Wheat

Fusarium head blight is a devastating disease of wheat and other small-grain cereals, causing grain yield reduction, reduced quality and mycotoxin contamination. This study was conducted in two districts of Kenya to determine the incidence of Fusarium species and mycotoxin contamination in freshly harvested wheat. A survey was carried out during the 2004 growing season in different agro-climatic zones to determine the presence of Fusarium head blight and weather conditions during the critical stages of wheat growth.