Integrating Phosphonate Fungicide And Variety Resistance In The Management Of Potato Late Blight

Potato is an important food and cash crop in sub-Saharan Africa highland regions. It production
in terms of yields have stagnated for over decades due to several factors including diseases. Late
blight caused by Phytophtliora infestans is one of the most devastating potato diseases in developing
countries and its management has been very costly and difficult endavour for most poor farmers.
The application of fungicides and development of resistance due to change in the population of

Management of late blight of potato and tomato by antibiotics produced by streptomyces species

This was a study undertaken to formulate antibiotics produced by Streptomyces sp. and test their efficacy
in control oflate blight disease of tomato and potato. It was also meant to establish mammalian toxicity
of these antibiotics. The study was carried out in the laboratory and in the greenhouse.
The isolates used were tentatively identified as Streptomyces sahachiroi ( isolate CS35) and Streptomyces
hygrostaticus or S. mitakaensis ( isolate 28P). They produced antibiotics on soybean media with 2%

Optimization of late blight and bacterial wilt management in potato production systems in the highland tropics of Africa

Late blight and bacterial wilt are two formidable disease constraints on potato and account for significant losses in Sub-Saharan Africa (SSA). In this chapter, various management techniques for late blight and bacterial wilt diseases are highlighted with examples drawn from diverse research. The modified disease management approaches include resistant cultivars, reduced fungicide applications, disease monitoring based on field scouting, cultural practices, post-harvest management and farmer training.

Bacterial Blights Of Beans (phaseolus Vulgaris L) caused by Xanthomonas Phaseoli (smith) Dowson, and X. phaseoli Var. fuscans ( Burk) Dowson In Kenya.

Xanthomonas phaseoli (Smith) Dowson, and X, phaseo1i var. fuscans (Burk) Dowson were isolated from blighted bean plants collected during a survey in small scale farms in Kenya. Common and fuscous blights of beans were prevalent in all bean growing areas, but reached epidemic proportions in a few areas such as Meru, Kitui, Machakos, Kakaraega, Embu, Trans-nzoia and Muranga. Common blight was severe in Meru with 12.9% incidence; Machakos, 11.0% and Kiambu and Muranga with 9.6% incidences each.

Determination of combining abilities for grain yield and grey leaf spot resistance among selected maize inbred lines

Maize is a staple food crop for about 90% of Kenyans. Its production by smallholder
farmers often plays a vital role in food security and alleviating poverty. Grey Leaf
Spot (GLS) caused by Cercospora zeae maydis significantly reduces maize yields in
farmers' fields. This study was carried out at three sites (KARI-Kiboko, Kabete Field
Station and KARI-Kakamega) in 2006 to determine the combining abilities for yield.
(j·LS resistance and other traits among seven selected maize inbred Iines CIVIL:204,

Studies on ascochyta blight on cowpea (vigna unguiculate l. (walp) and characterization of isolates of its causal organism, Ascochyta phaseolorum Sacc.

Cowpea leaf blight cause by Ascochyta phaseolorum Sacc. was found to be widely distributed in Kenya. Blight symptoms consisted of light to dark brown circular lesions with darker, regularly spaced, wavy concentric rings with occasional shot holes or tatterd leaf laminae. In a survey conducted from October to December 1980, the disease was found to occur in Kirinyaga, Kiambu, Meru, Siaya, Kisii, South Nyanza and Kakamega districts. The highest incidence of 46% and severity of 42% were recorded in Kakamega District.

Etiology, Effect of Soil pH and Sweetpotato Varietal Reaction to AlternariaLeaf Petoile and Stem Blight in Kenya

Leaf petiole and stem blight disease is commonly encountered on sweetpotato in Kenya. A study was carried out to confirm the causal agent of the disease in different agro-ecological zones of Kenya and determine the importance of soil pH as well as field conditions on disease development. Diseased leaf and vine tissues were collected and pathogen isolated. The Kabete, Kakamega, Busia (Alupe), and Kabondo isolates were identified as Alternaria bataticola while the Kisii isolate was identified as Alternaria alternata. Pathogenicity and virulence of different isolates of A. bataticola and A.

Analysis of social profitabiity and comparative advantage of domestic wheat production in Kenya

Kenya imports over 50% of its domestic wheat requirements. The
potential import bill for wheat is projected to reach US $ 545
million over the 1991-2000 period. Further, wheat imports
denominated in Kenya shilling, constitute more than 50% of the
grain imported into Kenya every year (table 1.3) . Given this
background, it lS seen that Kenya makes a large outlay on wheat
imports. This has prompted reactions from the government aimed at
trying to close the gap between domestic wheat production and

Costs, economies of size and resource use relationships in wheat production in Nakuru district, Kenya

Wheat production in Kenya has slumped during the last two
decades due to among other factors the high cost of productisn and
subdivision of former large-scale wheat farms. The broad objective
of this study was to examine cost behaviour under the prevailing
production environment of wheat industry to help identify ways of
overcoming this discouraging situation. Three hypotheses were
tested. These were: that rate of wheat output has no significant
effect on cost; that size of wheat enterprise does not

Studies on the efficacy and rate of application of some chemical fungicides, their mixtures and water extract of Tagetes minuta in the control of late blight of potato

Late blight of potato ( Solanum tuberosum) caused by Phytophthora infestans is the most destructive disease to the crop which is cultivated by large and small scale farmers mostly in Central, Rift Valley and Eastern provinces. At national level, about 3% of the total agricultural labour force is involved in potato production. A large amount of fungicide is used in the management of late blight as fanners commence fungicide application immediately after the emergence of the crop. Very few fanners use Ridomil alone in their spray programs.