Found 91 results

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A.N K’iri, P.M K, R.D. N, R.K M. Transmission and control of purple blotch in onions .; 1994.
King’iri AN;, Kimani PM;, Narla RD;, Mibey RK. "Transmission and control of purple blotch in onions."; 1994.
P.S O, R.D N, P.O A, J.O N. "Effect of infection level of sesame (sesamum indicum l). seed by Alternaria sesami on severity of Alternaria leaf spot." Tropical Agricultural Research and Extension. 1998;1(2):125-130.
Z.M K, Narla RD, Waudo SW. Pyrethrum Wilt Caused by Fusarium Oxysporum in Kenya.; 1998.
Kinyua ZM;, Narla RD;, Waudo SW. "Pyrethrum wilt caused by Fusarium oxysporum in Kenya."; 1998. Abstract

This article is about pyrethrum production in Kenya which is greatly constrained by a disease characterised by wilting and eventual death of pyrethrum plants. To date, Fusarium graminearum schwabe, F. solani (Mart.) Sacc., Rhizoctonia solani kuhn, Sclerotinia monor jagger, S. sclerotiorum (Lib) de Bary, and lesion nematodes (Pratylenchus spp.) have been associated with the wilt disease of pyrethrum. The study was carried out to determine the primary casual agent of the disease. Disease plant samples were collected from five pyrethrum growing areas, namely Kisii, Molo, Mwongoris, Sotik and Limuru for isolation and identification of pathogens associated with the disease.

Ojiambo PS, P.O A, Narla RD, Nyabundi JO. "Effect of plant age on sesame infection by Alternaria leaf spot." African Crop Science . 1999;7:91-96.
Kihurani AW;, Carey EE;, Narla RD. "First report of black rot disease of sweetpotato in Kenya.".; 2000.
P.S O, R.D N, P.O A, R.K M. "Infection of sesame seed by Alternaria sesame (Kawamura) Mohanty and Behera and severity of Alternaria leaf spot in Kenya." International Journal of Pest Management. 2000;46(20):121-124.
Ojiambo PS, Oyiecho PO, Mibey RK. "Tolerance level of alternaria sesami and the effect of seed infection on yield of sesame in Kenya.". 2000. AbstractWebsite

Field plots of sesame (Sesamum indicum) with six different levels of seed infection with Alternaria sesami were monitored for Alternaria leaf spot severity at Kibwezi, eastern Kenya. The aim of the study was to determine the effect of seed transmission of the pathogen on yield and tolerance level of the fungus in sesame seed. Increase in percentage leaf area diseased and percentage defoliation fitted the Gompertz model more closely than the logistic model. Areas under disease progress curves (AUDPC), infection and defoliation rates varied among the six infection levels. Disease severity increased with increase in seed infection and was least and most severe in plots established with seeds with 0 and 8% infection levels respectively. Yields ranged from 234.9 to 300.1 kg ha−1 compared with 312.5 kg ha−1 for the control, and losses due to seed infection ranged from 4% to 25%. Disease severity was negatively correlated with seed yield, 1000-seed weight and seeds per capsule. Alternaria leaf spot severity had a major effect on the seed weight component of yield. Tolerance level of A. sesami in sesame seed was determined to be less than 2%.

T.J A, R.D N, E.E C, R.W N. "Etiology of soil pH and sweet potato varietal reaction to Alternaria leaf petiole and stem blight in Kenya." African Crop Science . 2001;9(1):287-292.
E.K K, R.D N, R.K M, L.M.S A. Etiology of Septoria Leaf Spot of Cowpea (Vigna Unguiculata (L.) Walp.) in Kenya.. Maseno, Kenya: Maseno University; 2003.
Narla RD;, Kiprop EK;, Mibey RK;, Akundabweni LMS. "Etiology of Septoria Leaf Spot of Cowpea (Vigna Unguiculata (L.) Walp.) in Kenya.".; 2003.
P.S. O, R.K M, R.D. N, Ayiecho. "Field transmission efficiency of Alternaria sesame in sesame from infected seed." Crop Protection. 2003;22:1107-1115.
H.K W, R.D N, J.H N, L WH. "The status of Potato Leaf Roll Virus in Kenya." Plant Pathology . 2003;75(3):153-156.
Kiprop EK;, Narla RD;, Mibey RK;, Akundabweni LMS. "Chemical Control Of Septoria Leaf Spot On Cowpea (Vigna Unguiculata (L.) Walp,) In Kenya."; 2007. Abstract

Three foliar fungicides namely, Antracol, Kocide 101 and Folicur were evaluated for the control of Septoria leaf spot caused by S. vignicola V.G. Rao on cowpea [Vigna unguiculata (L.) Walp.] at two field sites in Kenya: Kabete and Katumani. The cowpea variety used was the high yielding Machakos 66 that was also susceptible to Septoria leaf spot. Reduction in disease incidence and severity of Septoria leaf spot on cowpea was obtained with the three fungicides. However, significant (P≤0.05) increase in seed yields was obtained when Kocide 101 and Antracol were applied to cowpea plants with the disease at Katumani. Folicur was found to be phytotoxic to cowpea plants and hence reduced plant dry weight and seed yield at both sites. Based on the cost-benefit analysis of the fungicides in the present study, Antracol and Kocide 101 are recommended for the control of Septoria leaf spot on high yielding cowpea varieties in arid and semi-arid areas. The Pearson correlation (r) between the disease incidence and seed yield was 0.75 (P=0.46), while that between disease severity and seed yield was 1.00 (P=0.01).

M.N M, R.D N, R.K M, F.W M. "Effect of plant extracts on growth of Alernaria porri (Ellis) Cif and other fungal pathogens of onion." Microbiol. Biotechnol. 2007;3(1):7-11.
Muthomi JW;, Riungu GM;, Ndung'u JK;, Narla RD. "Occurrence of wheat head blight and fusarium species infecting wheat."; 2007.
B M, Narla RD, Amata R, Olubayo F, Songa J, Kyamanyua S, Ateka EM. "Efficiency of cassava brown streak virus transmission by two whitefly species in coastal Kenya." General and Molecular Virology . 2009;1(4):040-045 .efficiency_of_cbvs_transmission_by_2_whitefly_species_in_coastal_kenya1.pdf
Kimenju JW, Odero GOM, Mutitu EW, Wachira PM, Muiru WM. "Suitability of Locally Available Substrates for Oyster Mushroom (Pleurotus ostreatus) Cultivation in Kenya.". 2009. AbstractWebsite

This study aimed at evaluating the suitability of selected substrates for mushroom production. Ten different substrates namely water hyacinth ( Eichhornia crassipes ), maize cobs ( Zea mays ), coconut fibre ( Cocos nucifera ), finger millet straw ( Seteria microcheata ), banana fibre ( Musa sp.), sawdust ( Eucalyptus sp.), rice straw ( Oryza sativa ) bean straw ( Phaseolus vulgaris ) and wheat straw ( Tritichum aestivum ) were tested for their suitability in mushroom production. Plastic bags were filled with 250 g of substrate and arranged in a randomized complete block design. The substrates had a significant (p≤0.05) effect on days to pinning, number of caps and biological efficiency. Compared to the control, which pinned at 28 days, maize cobs, sawdust and coconut fiber had short pinning durations of 19, 22 and 23 days, respectively. With the exception of sawdust, water hyacinth and maize cobs, the rest of the organic substrates significantly increased the marketable caps of the oyster mushroom. The straws, namely, bean, rice, finger millet and wheat had the highest biological efficiency in decreasing order of 106, 92, 85 and 77%, respectively. Stipe length was longest in oyster mushroom grown on bean straw, followed by finger millet straw, maize cobs, banana fiber and shortest in sawdust. Mushroom yield was, 80, 78, 76, 73 and 68%, higher in bean straw, rice straw, millet straw, wheat straw and banana fibre treatment compared to the control. Mushroom yields on sawdust were 60% lower than the control. In descending order of suitability bean, rice, finger millet and wheat straws can be recommended for oyster mushroom production.

Luambano N;, Kimenju JW;, Narla R;, Waceke JW. "Colonisation of the Rhizosphere of plants which are poor host to root-knot nematodes by the biological agent Pochonia chlamydosporia."; 2011. Abstract

Management of root-knot nematodes (Meloidogyne spp.,) using fungi that parasitize eggs of root-knot and cyst nematodes has been gaining popularity. Application of this fungus to plants that are poor host to root-knot nematodes has shown good results. This study was conducted to screen plants that support growth of Pochonia chlamydosporia on its rhizosphere. Seedlings of cabbage, sunhemp, maize, velvet bean, African marigold and tomato were planted in pots containing sterilized soil which had Pochonia chlamydosporia. Thirty days after planting, the fungal propagules in the soil and roots increased significantly (P<0.05) in all plants with the exception of velvet beans. Ninety days after planting, the counts of the fungal propagules taken from the soil were significant higher (P<0.05) in the rhizosphere where maize was planted than in other plants. This study concluded that maize is a promising rotational in system where P. chlamydosporia is used as a biocontrol agent.

Subramanian S, H.R P, Birithia, R. S, Muthomi O, P JS, R.D N. "Diversity and distribution of Iris yellow spot virus infecting onions ." Narla, R.D. 2011;101(S172).
R.O N, Kiplagat KW, Kiplagat KW, R.D N, S.J S, J.N K, J.A L. "Early and late harvest agronomic performance and stability of R-free late blight potato genotypes." Crop Improvement. 2011.
R.D N, Muthomi JW, Gachu SM, Nderitu JH, Olubayo FM. "Effect of Intercropping bulb onion and vegetables on purple blotch and downy mildew." Journal of Biological Sciences . 2011;11(1):52-57.effect_of_intercropping_bulb_onion_and_vegetables.pdf
S BRS, Pappu HR, Sseruwagi, P. M, R.D N. "First Report of Iris yellow spot virus in Onion in Kenya and Uganda." Plant Disease . 2011;95(1195).
Muthomi JW;, Gachu SM;, Narla RD;, Nderitu J. "Management of thrips in bulb onions using vegetable intercrops."; 2011.
WAHOME SW, Kimani PM, Muthomi JW, Narla RD, BURUCHARA1 R. "MULTIPLE DISEASE RESISTANCE IN SNAP BEAN GENOTYPES IN KENYA." African Crop Science Journal. 2011; 19( 4):289-302.multiple_resistance_in_snap_bean_genotypes_in_kenya.
J. M, Narla RD, Musyimi SL, WAGACHA JOHNMAINA. "Occurrence of Fusarium species and associated T2-toxin in Kenyan wheat." Agriculture Science and Technology. 2011;3(1):24-34.occurrence_of fusarium_species_and_associated_toxins.
Subramanian BR, S.Villinger, Muthomi J, R.D NJ, Pappu HR. "First report of Tomato yellow ring virus (Tospovirus, Bunyaviridae) Infecting tomatoes in Kenya.". 2012;96(1384).
S.M.1 G, J.W.2 M, R.D.2 N, J.H.2 N, F.M.2 O, J.M.3 W. "Management of thrips (Thrips tabaci) in bulb onion by use of vegetable intercrops." International Journal of AgriScience Vol. 2(5): 393-402, May 2012. 2012;2(5):393-402.management_of_thrips_in_bulb_onion_by_use_of_veg_intercrops.
R B, S S, J V, Muthomi J, R.D N, H.R. P. Resistance Screening of onion cultivars to Thrips and Iris yellow spot virus. Daegu-Korea; 2012.
WAHOME SW, P.M. Kimani, J.W. Muthomi, Narla RD. "Quality and yield of snap bean lines locally developed in Kenya." International Journal of Agronomy and Agricultural Research (IJAAR). 2013;3(7):1-10.quality_and_yield_of_snap_bean_lines_locally_developed_in_kenya.pdf
Birithia R;, Subramanian S;, Villinger J;, Muthomi J;, Narla RD;, Pappu HR. "Distribution of tospoviruses, Iris yellow spot virus infecting onions in Kenya."; Submitted.

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