Head blight of wheat in Kenya and contamination of grain with mycotoxin producing Fusarium species

The study was carried out during the 2006 cropping season in Nakuru district, Kenya. Incidence and severity of head blight were determined and pathogens isolated from diseased wheat heads, wheat and maize kernels. Mycotoxin deoxynivalenol content in grain was determined by direct competitive Enzyme-Linked Immunosorbent Assay (ELISA). Pathogenicity of different Fusarium species isolated from wheat was determined by inoculation onto wheat ears in greenhouse. Head blight was highly prevalent (90-100%) and mean incidence and severity ranged from 4 to 9% and 15 to 37%, respectively.

The occurrence of Fusarium species and mycotoxins in Kenyan wheat

presence of head blight-causing Fusarium species. Fungal contaminationwas determined by isolation on
agar media, while mycotoxin analysis was by direct competitive enzyme-linked immunosorbent assay
(ELISA). The wheat grain samples were highly contaminated with fungi, especially Epicoccum, Alternaria
and Fusarium species. The mean Fusarium infection rate varied from 13% to 18%, with the major head
blight-causing species being Fusarium poae, Fusarium graminearum, Fusarium equiseti and Fusarium

Occurrence of f u s a r i u m head blight, associated mycotoxins and resistance of wheat germplasm

F u s a r i u m head blight (FHB) is an important disease of wheat that reduces yield and quality
through contamination with mycotoxins detrimental to human and livestock health. Major
wheat varieties grown in Kenya are susceptible to FHB and there is no known source of
resistance to the disease available. This study was carried out to determine the occurrence of
F u s a r i u m head blight, associated mycotoxins and the level of susceptibility of wheat
germplasm to FHB and deoxynivalenol (DON) contamination.

Reaction of some Kenyan wheat cultivars to head blight after inoculation with Fusarium graminearum

Eight cultivars of wheat that are commonly grown in Nakuru and Nyandarua districts of Kenya were tested for their susceptibility to Fusarium head blight (scab) under green house conditions. The cultivars were inoculated with mixed inoculum derived from three pathogenic isolates of Fusarium graminearum that had previously been isolated from wheat. Head blight severity was assessed using a 1-9 scale based on proportion of spikelets bleached and the area under disease progress curve was derived from the disease severity data.

Fusarium and mycotoxin contamination in freshly harvested wheat grain in Kenya

A survey was carried out during the 2004 wheat-cropping season in 6 agro-ecclogical zones to determine fusarium contamination of freshly harvested wheat grain. This was done by plating in culture media. Contaminations with mycotoxins t!cnxynivalcnol, zenralenonc and aflatoxin B I were determined by competitive EUSA. Farmers indicated presence ol'hcnd blight 111 wheat fields and occurrence of wet weather during flowering. Wheat residue was mainly directly grazed to animals in the field or ploughed in. Most popular rotation was wheal-maize followed by continuous wheat cropping.

Occurrence of Fusarium species and associated T2-toxin in Kenyan wheat

Survey covering 120 wheat fields was conduc- ted in three wheat-growing districts of Kenya during the 2008 cropping season to determine the incidence of Fusarium head blight (FHB) and T2-toxin contamination in grain. FHB incidence was determined as the number of blighted ears per 10 m2. Information gathered included wheat production practices, rainfall and temperature data. Fungal pathogens were isolated from wheat stems, heads, straw, grains and soil and identified based on cultural and morphological characteristics.

Management of Fusarium head blight of wheat and deoxynivalenol accumulation using antagonistic microorganisms

Laboratory and green house studies were conducted at the Faculty of Agriculture, University of Nairobi, to evaluate the efficacy of Epicoccum sp., Alternaria sp., Trichoderma sp. and Bacillus sp. in control of Fusarium head blight of wheat caused by F. graminearum. Fungicides folicur® and copper oxychloride were used as standard checks. Laboratory assay was carried out by paired cultures and antagonism was measured as reduction in pathogen colony diameter.

Fungal and mycotoxin contamination of wheat from Nakuru and Nyandarua districts of Kenya and pathogenicity of fusarium species on wheat

Mycotoxin poisoning resulting from contaminated cereal grains has become rampant in
Kenya. Understanding the fungal causes and management is important both to the farmers and
the consumers of the cereal grains and their products.
A survey was carried out during the 2004 wheat growing season in Nakuru and Nyandarua
districts. A total of 9 agroecological zones were selected, within which 10 farms in each
agroecological zone were randomly selected. A total of 89 farmers were interviewed on wheat

Colonization of wheat seedling leaves by Fusarium species as observed in growth chambers: a role as inoculum for head blight infection?

Fusarium species involved in the Fusarium head blight complex in Western Europe were investigated for their potential to infect and colonize non-damaged wheat leaves and to produce conidia on senescing wheat leaves incubated at high relative humidity. Fusarium avenaceum, Fusarium culmorum, Fusarium graminearum, Fusarium poae and Fusarium tricinctum did not directly penetrate the leaf tissue after conidia germination on the leaf surface. Germ tubes grew on the host surface for 24–36 hr forming a mycelial network.

Susceptibility of Kenyan wheat varieties to head blight, fungal invation and Deoxynivalenol accumulation inoculated with Fusarium graminearum

Fifteen wheat varieties commercially grown in Kenya were tested for their susceptibility to head blight and mycotoxin accumulation after inoculation with Fusarium gramineanuu in pot experiments. The strain or the pathogen used had been isolated from wheat collected in different growing areas or Kenya. Head blight suscep¬tibility was assessed as the percentage or spikclcts bleached and area under disease progress curve: kernel colonization by fungal mycelium was determined as ergosterol content. All varieties were round to be moderately to highly susceptible. However.

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