Department of Plant Science
http://repository.chuka.ac.ke/handle/chuka/421
2022-04-14T20:24:55ZIncidence and Severity of Turcicum Leaf Blight Caused by Exserohilum turcicum (pass.) Leonard and Suggs) on Sorghum Populations in Different Regions of Tharaka Nithi County, Kenya
http://repository.chuka.ac.ke/handle/chuka/15769
Incidence and Severity of Turcicum Leaf Blight Caused by Exserohilum turcicum (pass.) Leonard and Suggs) on Sorghum Populations in Different Regions of Tharaka Nithi County, Kenya
O. Ogolla, Fredrick; M. Muraya, Moses; O. Onyango, Benson
Sorghum (Sorghum bicolor (L.) Moench) is a drought tolerant food crop preferred by subsistence farmers in dry areas which experience low annual rainfall. However, Turcicum Leaf Blight (TLB) caused by Exserohilum turcicum has threatened sorghum production in the world. New sorghum varieties have been introduced into the Kenyan production systems, including the drier parts of Tharaka Nithi County to boost yield and thus meet the increased demands for food and as a raw material by brewing industries. Nonetheless, challenges due to infection by TLB have negatively impacted on sorghum production resulting from damaged photosynthetic leaves. This study was conducted to determine the incidence and severity of TLB on sorghum populations indifferent regions of Tharaka Nithi County. Sorghum farms in eleven villages for the study were selected by multistage random sampling. The study was conducted between the month of January and June 2018. Data analysis was done by SAS software version 9.3 and significantly different means separated using LSD test at 5% probability level. There was statistically significant difference in the severity and incidence of E. Turcicum leaf blight on sorghum population from different regions in Tharaka Nithi County (P<0.05). Disease TLB occurred in all the villages surveyed though at different frequencies. The disease incidence was higher at Kithaga, and Nkairini recording 74.45% and 55.93%. and lowest at Gatuntu and Gituntu both recorded the disease incidences 12.22%. Thus, farmers should be educated on sorghum TLB management for increased sorghum production and higher income to farmers.
2019-01-01T00:00:00ZCultural, Morphological and Biochemical Identification of Xanthomonas Spp the Causative Agent of Bacteria Leaf Spot in Tomatoes in Wanguru, Mwea, Kirinyaga County, Kenya
http://repository.chuka.ac.ke/handle/chuka/15768
Cultural, Morphological and Biochemical Identification of Xanthomonas Spp the Causative Agent of Bacteria Leaf Spot in Tomatoes in Wanguru, Mwea, Kirinyaga County, Kenya
Fredrick O. Ogolla; DaisyB. Neema
Bacteria diseases are major constraints in commercial
agriculture. Bacteria diseases have continuously caused huge loss
to both conventional and organic farming systems globally.
Bacteria leaf spot is a tomato disease of concern whose
management remains a challenge across the globe. The pathogen
Xanthomonas campestris pv vesicatoria the causative agent of leaf
spot in tomato has been isolated and positively identified in many
countries to enable control. In Kenya, tomato farmers have
experienced losses associated with bacterial diseases despite using
available control strategies. Application of control mechanisms
by majority of farmers heavily rely on symptoms on plants other
than laboratory facts on pathogen identification. As such wrong
chemicals have been applied which have led to development of
resistance due to pathogen evolution. Scientific identification of
pathogen is necessary to enable application of accurate and
effective management strategy. Nonetheless, this has scarcely
been done for tomato bacteria diseases in Kenya.
The objective of this study was to isolate and identify bacteria
leaf spot pathogen of tomato from Wanguru area in Mwea,
Kirinyaga county in Kenya using nutrient agar, differential
staining and selected biochemical methods. A total of ten tomato
heavily infected leaves were selected randomly from different
farms. The colonies were generally yellow on the surface of
nutrient agar. Results of differential staining showed gram
negative rods while biochemical tests slightly varied. Based on
totality of cultural, morphological and biochemical tests results,
we concluded that Xanthomonas campestris pv vesicatoria is
responsible for leaf spot tomato disease in Wanguru. However,
we recommend the inclusion of molecular tool for proper
identification.
2019-04-01T00:00:00ZIncidence and Severity of Solanum lycopersicumBacterial leaf spot Caused by Xanthomonad species in Farms in Wanguru, Mwea, Kirinyaga County, Kenya
http://repository.chuka.ac.ke/handle/chuka/15767
Incidence and Severity of Solanum lycopersicumBacterial leaf spot Caused by Xanthomonad species in Farms in Wanguru, Mwea, Kirinyaga County, Kenya
B. NEEMA, DAISY; OGOLLA O., FREDRICK
Demand for tomato has increased tremendously
but its production has been bedeviled by phytopathogens
such as bacteria leaf spot. Studies have reported cases of
bacteria leaf spot associated with tomato losses in many
tomato production regions globally. However, despite
persistent of tomato diseases in different agroecological
regions in Kenya, there is scanty information on
incidences and severity of individual diseases. This study
was done to determine the incidence and severity of
bacteria leaf spot of tomato in Wanguru in Mwea,
Kirinyaga county in Kenya between February and April
2019. A total of ten tomato farms were selected randomly
for the surveyed of incidence and severity bacteria leaf
spot.From these ten farms, a total of 3000 tomato leaves
in 100 tomato plants were assessed. Severity was scored by
rating on a scale of 0 – 5. Data collected was subjected to
analysis of variance using SAS software version 9.3 and
significant means separated using least significance
difference (LSD). Results showed that bacterial leaf spot
incidence and severity was significant (p<0.05). Bacteria
leaf blight was observed in all farms but at lower rates.
However, the incidence was below 15% with farm 7
recording mean of 13%. The lowest incidence was
observed in farm 3 and 5 recording 8.333%. Severity
observed in all the farms was below 35% with farm 7
recording severity mean of 33.333% while farm 5
recorded lowest severity mean of 16.000%. This study
therefore reports the incidences and severity of bacteria
leaf spot caused by Xanthomonads species complex
though at lower rates. The study should be extended to
other tomato production areas in Mwea.
2019-04-01T00:00:00ZIntegrated Effect of Rhizobium Inoculation and Phosphorus Application on Tissue Content, Symbiotic and Phosphorus use Efficiency in Soybean Production
http://repository.chuka.ac.ke/handle/chuka/15765
Integrated Effect of Rhizobium Inoculation and Phosphorus Application on Tissue Content, Symbiotic and Phosphorus use Efficiency in Soybean Production
Mulambula, S.; Gathungu G. K; Ndukhu H. O.; Ogolla F. O.
Soybean (Glycine max) is an important legume crop that is cultivated all over the world as livestock
feed, food for human consumption, soil fertility improvement and industrial products such as candles and paints.
However, Nitrogen (N) and phosphorus (P) nutrient have been attributed to the decline in soybean yields.
Furthermore, scanty information is documented on P-efficient soybean genotypes, which are a sustainable P
management strategy for enhancing symbiotic efficiency (SEF) and phosphorus use efficiency (PUE). As a
solution, field experiment was conducted at Chuka University farm to evaluate the integration effect of rhizobium
inoculation (R) and P on tissue nutrient content, SEF and PUE in soybean production in Meru South Sub County.
Two cultivations (Trial I and II) were done in 2018. Treatments included; three rates of R (0, 100 and 200 g ha-1
),
three rates of P (0, 20 and 30 kg- ha-1
), either applied alone or integrated and soybean genotypes (SB19 and SB24).
Both Trials were laid out in a randomized complete block design in split-split plot arrangement with each treatment
replicated thrice. Genotypes were assigned main plot, R subplots and P in sub-subplots. Data collected was
subjected to analysis of variance using the Scientific Analysis System SAS and significantly different means
separated using Tukey test at (p≤0.05). The results showed significant difference in N and P tissue content, SEF
and PUE for SB19 and SB24 genotypes in both Trials at (p≤0.05). The highest N tissue content of between 1.73%
and 9.10% was observed when integration of R and P were applied at the rate of 200 g and 30 kg for SB19 and
SB24 in both Trials. While R and P at the rate of 200 g and 30 kg per ha showed the highest P content of between
849.6 ppm and 955.0 ppm in both Trials. The highest SEF recorded was 207% and 261%, and 201% and 227%
in Trials I and II, respectively. The PUE was highest when R and P was applied at the rate of 200 g and 30 kg per
ha for SB19 and SB24 soybean in both Trials. Integration of R and P at the rate of 200 g and 30 kg ha-1 and
adoption of either SB19 or SB24 showed a potential in enhancing soybean cultivation.
2019-10-01T00:00:00Z