Cassava brown streak disease (CBSD) is an important disease causing losses of up to 70% in the most susceptible cultivars. Its effects include: reduced root quality due to pitting, root constriction and necrosis, and reduced number and weight of tuberous roots. To contribute to CBSD management, a study was conducted to: (i) Screen East African cassava landraces and F1 populations for CBSD resistance; (ii) Analyse symptom expression and virus accumulation in CBSV graft inoculated cassava varie...
Abstract: Agriculture in Sub-Saharan Africa is predominantly subsistence and perennial food deficits, cyclic famines characterize it, and poverty is prompted largely by erratic rainfall patterns, declining soil fertility, and pests and diseases. In Kitui County, farmers are largely small-scale and face various challenges: from poor soil fertility to erratic rainfall. The farmers, too, have not been spared by the pest menace. Consequently, they have resorted to unwarranted and unregulated app...
Abstract: The study assesses the risk behavior, perceived vulnerability and adaptation behavior of farm households and the determinants using an integrative insight of the social-ecological system model and semi-quantitative research methodology. Besides, RSSH theory, integrative vulnerability analysis theory, and SMMA were applied to explain the farm households’ risk behavior, perceived vulnerability and adaptation behavior respectively. Survey data collected from the randomly selected 39...
Abstract: Weeds are one of the most damaging obstructions in sugarcane cultivation systems. The various cycles of sugarcane cultivation result in degrees of weed severity in which each species requires a different weed control method, the most popular of which is the pre-emergence herbicide method. The previously used pre-emergence herbicide application date in Wonji/Shoa sugar factory was applied mostly in the wide range of days within the standard (7-15 spray interval days). Due to this re...
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Abstract: Studies were conducted at the International Centre of Insect Physiology and Ecology, Mbita Point Field Station (MPFS) fana and the Lambwe Valley fanaer's field during 1983 - 1985 , to detenaine the natural population changes of Maruca testulalis Geyer (Lepidoptera; Pyralidae). The role of natural enemies, host plants and cliaetic factors on natural population, development and survival of M· testulalis was investigated. Further investigations on the biology of Tetrastichus sesaaiae...
Abstract: Amaranth is one of the African indigenous vegetables that is gaining popularity due to its nutritional, medicinal and economic values. Its potential as a source of food security in East Africa and most parts of the world has heightened demands for the once neglected crop. In Kenya and Tanzania, the Lepidopteran defoliators are important pests of the crop which can cause up to 100% yield loss. Little information on the population dynamics of these pests make their management difficu...
Abstract: Three neem-based biopesticides, namely Achook (0.15% Azadirachtin), Neemroc (0.03% Azadirachtin + 32% neem oil) and Neem + Com (0.03% Azadirachtin + 32% com oil) and one garlic-based product, namely GC- mite (40% garlic extract), were evaluated under laboratory, greenhouse and field conditions for their efficacy against red spider mites (Tetranychus evansi Baker and Pritchard) on tomatoes (Lycopersicum esculentum L.). A synthetic acaricide, namely Omite (57% propargite) was also us...
Abstract: Metarhizium anisopliae isolate ICIPE69 is a highly virulent fungal pathogen against several thrips species such as western flower thrips (Frankliniella occidentalis), bean flower thrips (Megalurothrips sjostedti), onion thrips (Thrips tabaci) and others infesting key vegetable crops in Africa. Recently the isolate has been commercialized for pest control under the trade name, Campaign ®. The efficacy of the entomopathogenic fungi is known to be influenced by the prevailing climati...
Abstract: Plant-parasitic nematodes, in particular Meloidogyne spp., cause significant yield reduction in commercial pineapple (Ananas comosus) worldwide. In Kenya limited studies have been conducted on nematodes in pineapple although the main commercial producer in Kenya has sole mandate to use Telone II (1, 3-Dichloropropene) indicating the seriousness of the problem. The current study was conducted to provide an update on the occurrence of plant-parasitic nematodes in commercial pineapple...
Abstract: Laboratory studies were performed on tobacco spider mites (Tetranychus evansi) collected from Chinamhora and Mutoko to investigate grower claims of resistance to commonly used acaricides. Bioassays of T evansi collected from tomatoes showed presence of resistance to dimethotae, malathion, abamectin and amitraz. The RF values for Chinamhora were 1.2 for abamectin, 1.0 for malathion and 1.4 for an1itraz and dimethoate. For Mutoko RF values were 1.2 for aban1ectin and malathion, 1.4 f...
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Abstract: Tephritid fruit flies are among the notorious pests of horticultural crops in Kenya and have been documented to cause yield losses of 30-100%. Tephritid fruit flies from the Bactrocera and Dacus genera have been identified on cucurbit farm traps, however, their losses have not been quantified. Therefore, this study was conducted to determine the occurrence, diversity and host preference of tephritid fruit flies infesting cucurbit and other horticultural crops in coastal Kenya. Infe...
Abstract: French bean, (Phaseolus vulgaris) L. is key commodity for export in Kenya. The value of export increased from 4,466.7 Kenya Shillings in 2002 to 4,466.7 Kenya Shillings in 2006. Production of French beans is constrained by many factors including pests, lack of capital and credit facilities, fluctuation in demand, and difficult accessibility to the market, and improper grading. The major arthropod insect pests of French beans include bean stem maggots, flower thrips, pollen beetles,...
Abstract: Plant parasitic nematodes (PPN) are biotic constraints to crop production worldwide resulting in significant yield losses. Management of these nematodes has primarily depended on chemical nematicides; but due to the increased pressure for more economic and environmentally friendly strategies, alternative methods like organic and conventional amendments, have been considered. To test the efficacy of conventional and farmer practice systems against organic farming in the suppression ...