Response of Ugandan common bean varieties to Pseudocercospora griseola and Angular leaf spot disease development in varietal mixtures     

N. Olango  G. Tusiime  J.W. Mulumba  R. Nankya  C. Fadda  D.I. Jarvis 《国际虫害防治杂志》2017,63(2):119-127

Angular leaf spot (ALS) is one of the most economically important bean diseases in Africa. One promising control option for the disease is the use of mixtures of resistant and susceptible varieties. This research evaluated (1) the reaction of farmer preferred bean varieties to ALS in the screenhouse and on-station and (2) the effect of different spatial arrangements of resistant and susceptible bean varieties on ALS disease development. For the latter, five mixture combinations and two controls were laid out in a Randomized Complete Block Design having three replicates. Analysis of variance and least significant differences (LSDs) were used to compare disease levels in both studies above. Varietal screening showed significant differences in varietal reaction to ALS. Screenhouse disease scores ranged between 0 and 5, compared to 0.7–3.9 in the field. For the varietal mixture trial, the lowest disease levels and the highest mixture efficiencies were observed for the combination of equal proportions of the susceptible and resistant varieties randomly mixed (even mixture) prior to planting. We conclude that even mixtures reduce the amount of ALS disease that develops in the season.  相似文献   

Tree establishment and management on farms in the drylands: evaluation of different systems adopted by small-scale farmers in Mutomo District,Kenya     

Geoffrey Ndegwa  Miyuki Iiyama  Dieter Anhuf  Udo Nehren  Sabine Schlüter 《Agroforestry Systems》2017,91(6):1043-1055

Agroforestry systems in Sub-Saharan African drylands are complex and heterogeneous in nature even under similar biophysical conditions. This can be attributed to household needs and socioeconomic status which influence the species and utility of the adopted trees. This has an impact on the trees establishment and management system through planting or Farmer Managed Natural Regeneration (FMNR). This study evaluates how trees for different utilities are managed and which socioeconomic factors influence these decisions. The study used primary data collected in Mutomo District, Kenya through a household survey based on a structured questionnaire. A paired sample t-test was done to assess the preferred mode of adopting trees for different utilities while factor analysis was used to characterize the households as either planting trees or practicing FMNR. Multiple linear regression using household regression factor scores as independent variables and socioeconomic indicators as dependent variables was done to ascertain which socioeconomic factors affect tree adoption. The results show that trees planted were mostly exotic species valued for their nutrition and commercial value, while FMNR was used for subsistence products and environmental services. Household size, livestock levels and mobility had a positive correlation with tree planting, while income, access to markets and roads had an inverse correlation. Access to natural woodland, distance to the nearest motorable road and land size had a positive correlation with tree protection. It is hoped that this knowledge will act as a reference point when designing agroforestry projects in similar areas to ensure they are more aligned to specific site and household conditions.  相似文献   

Biomechanical Comparison of 2 Veterinary Locking Plates to Monocortical Screw/Polymethylmethacrylate Fixation in Canine Cadaveric Cervical Vertebral Column          下载免费PDF全文

Bianca F. Hettlich  Geoffrey T. Fosgate  Alan S. Litsky 《Veterinary surgery : VS》2017,46(1):95-102

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Displacement of US‐1 clonal lineage by a new lineage of Phytophthora infestans on potato in Kenya and Uganda          下载免费PDF全文

A. W. Njoroge  G. Tusiime  G. A. Forbes  J. E. Yuen 《Plant pathology》2016,65(4):587-592

Phytophthora infestans, the pathogen responsible for causing late blight in potato and tomato, is a rapidly evolving and highly adaptable pathogen. Following the appearance of a new clonal genotype in Kenya (KE‐1 lineage) in 2007, there was a need to document possible displacement of the US‐1 genotype by the newer lineage. Samples from Kenya (260) collected on potato and from Uganda collected on potato (134) and tomato (32) were genotyped with simple sequence repeat (SSR) and mitochondrial DNA haplotype (mtDNA) markers. Results show that, four years after its discovery, the KE‐1 lineage has completely displaced the US‐1 lineage on potato in Kenya. The KE‐1 lineage has also migrated into Uganda through the eastern part of the country that borders western Kenya. All potato samples from eastern Uganda were of the KE‐1 lineage. Moreover, samples from eight fields in western Uganda were also of the KE‐1 lineage, which is in agreement with an ongoing westward displacement. However, the new lineage has not displaced the old lineage on tomato, as all samples from tomato were US‐1. Principal coordinate analysis (PCA) scatter plots revealed clustering that indicated separation between the lineages and also between the subpopulations of the US‐1 lineage on potato and tomato.  相似文献   

Detection of viral hemorrhagic septicemia virus by quantitative reverse transcription polymerase chain reaction from two fish species at two sites in Lake Superior     

Cornwell ER  Eckerlin GE  Getchell RG  Groocock GH  Thompson TM  Batts WN  Casey RN  Kurath G  Winton JR  Bowser PR  Bain MB  Casey JW 《Journal of aquatic animal health》2011,23(4):207-217

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Strategies for bacterial tagging and gene expression in plant-host colonization studies     

Humberto J.O. Ramos  M. Geoffrey Yates  Emanuel M. Souza 《Soil biology & biochemistry》2011,43(8):1626-1638

Bacteria are extraordinarily diverse microorganisms with a huge potential to benefit environmental and agricultural systems. Comprehensive studies in complex habitats such as soils and plants have led to the development of genetic tools to evaluate gene expression and bacterial colonization under controlled or environmental conditions and to obtain genetically engineered organisms for environmental release. In addition, current advances in genomic and metagenomic research will add to the number of genes with potential for biotechnological applications, which will require the development of appropriate genetic systems to fulfill their potential for both industrial and agricultural applications. The aim of the present review is to assess the approaches and recent progress in vector design and genetic tools to study and manipulate plant-bacterial interactions, as well as strategies to construct genetically modified strains for environmental release.  相似文献   

Increasing consumption of ultra-processed foods and likely impact on human health: evidence from Brazil     

Monteiro CA  Levy RB  Claro RM  de Castro IR  Cannon G 《Public health nutrition》2011,14(1):5-13

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Cardiovascular-renal axis disorder and acute-phase proteins in cats with congestive heart failure caused by primary cardiomyopathy     

Mengmeng Liu  Liza S. Köster  Geoffrey T. Fosgate  Christopher C. Chadwick  Íñigo Sanz-González  Peter David Eckersall  Paul R. Wotton  Anne T. French 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2020,34(3):1078-1090

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Assessing Repeated Oxalic Acid Vaporization in Honey Bee (Hymenoptera: Apidae) Colonies for Control of the Ectoparasitic Mite Varroa destructor     

Jennifer A Berry  Lewis J Bartlett  Selina Bruckner  Christian Baker  S Kris Braman  Keith S Delaplane  Geoffrey R Williams 《Journal of insect science (Online)》2022,22(1)

The American beekeeping industry continually experiences colony mortality with annual losses as high as 43%. A leading cause of this is the exotic, ectoparasitic mite, Varroa destructor Anderson & Trueman (Mesostigmata: Varroidae). Integrated Pest Management (IPM) options are used to keep mite populations from reaching lethal levels, however, due to resistance and/or the lack of suitable treatment options, novel controls for reducing mites are warranted. Oxalic acid for controlling V. destructor has become a popular treatment regimen among commercial and backyard beekeepers. Applying vaporized oxalic acid inside a honey bee hive is a legal application method in the U.S., and results in the death of exposed mites. However, if mites are in the reproductive stage and therefore under the protective wax capping, oxalic acid is ineffective. One popular method of applying oxalic is vaporizing multiple times over several weeks to try and circumvent the problem of mites hiding in brood cells. By comparing against control colonies, we tested oxalic acid vaporization in colonies treated with seven applications separated by 5 d (35 d total). We tested in apiaries in Georgia and Alabama during 2019 and 2020, totaling 99 colonies. We found that adult honey bees Linnaeus (Hymenoptera: Apidae), and developing brood experienced no adverse impacts from the oxalic vaporization regime. However, we did not find evidence that frequent periodic application of oxalic during brood-rearing periods is capable of bringing V. destructor populations below treatment thresholds.  相似文献   

Response of the german cockroach Blattella germanica (L.) to a light source following exposure to surface deposits of insecticides     

Stephanie M. Miall  Geoffrey N. J. Le Patourel 《Pest management science》1989,25(1):43-51

Adult male German cockroaches were exposed to surface deposits of insecticides for 5 min in the central compartment of a three-compartment choice chamber illuminated at one end. They were then allowed access to the escape compartments and their distribution recorded over the subsequent 60 min. Cockroaches exposed to pyrethroid insecticides rapidly accumulated in the escape compartment closest to the light source; the same effect was observed to a lesser extent following exposure to propoxur. Boric acid and bendiocarb deposits inhibited the movement of the cockroaches away from the light source, and fenitrothion deposits delayed it. Dieldrin had no effect on the distribution of cockroaches within the choice chamber. The reversal of the normal tendency of German cockroaches to move from a light area to a dark harbourage following exposure to pyrethroids may contribute to the flushing action observed when these chemicals are used for control of B. germanica populations.  相似文献