Ecological determinants and risk areas of Striga hermonthica infestation in western Kenya under changing climate     

Emily Kimathi  Elfatih M. Abdel-Rahman  Catherine Lukhoba  Asaah Ndambi  Bester Tawona Mudereri  Saliou Niassy  Henri E. Z. Tonnang  Tobias Landmann 《Weed Research》2023,63(1):45-56

Striga hermonthica (Del.) Benth is a parasitic weed that is damaging major cereal crops in sub-Saharan Africa (SSA). Although Striga is recognised as an agricultural scourge, there is limited information available indicating the extent of its growth and spread as impacted by the changing climate in Kenya. This study investigated the impact of current climate conditions and projected future (2050) climate change on the infestation of Striga hermonthica in the western Kenya region. Specifically, the study aimed to predict Striga hermonthica habitat suitability in five counties in the western Kenya region through using the maximum entropy (MaxEnt) model and bioclimatic, soil, topographic and land use, and land cover (LULC) variables. Striga hermonthica geolocations were collected and collated and ecological niche models were developed to determine the habitat suitability. The results showed that approximately 1767 km² (10% of the total study area) is currently highly suitable for Striga hermonthica occurrence. The future projections showed a range between 2106 km² (19% of the total study area) and 2712 km² (53% of the total study area) at the minimum carbon (RCP 2.6) and the maximum carbon emission scenarios (RCP 8.5) respectively. Elevation, annual precipitation, LULC, temperature seasonality and soil type were determined to be the most influential ecological predictor variables for Striga hermonthica establishment. The study revealed the importance of using climate, soil, topographic and LULC variables when evaluating agricultural production constraints such as Striga's prevalence. The methodology used in this study should be tested in other Striga affected areas.  相似文献   

Bovine respiratory syncytial virus and bovine coronavirus in Swedish organic and conventional dairy herds     

Cecilia Wolff  Ulf Emanuelson  Anna Ohlson  Stefan Alenius  Nils Fall 《Acta veterinaria Scandinavica》2015,57(1)

Background

Infections with bovine respiratory syncytial virus (BRSV) and bovine coronavirus (BoCV) are endemic to the cattle populations in most countries, causing respiratory and/or enteric disease. It has been demonstrated that herds can remain free from these infections for several years also in high prevalence areas. Organically managed (OM) dairy herds have been shown to have lower seroprevalence of both viruses compared to conventionally managed (CM) herds. The objective of this study was to challenge the hypothesis of a lower occurrence of BRSV and BoCV in OM compared to CM dairy herds.In November 2011, May 2012 and May 2013 milk samples from four homebred primiparous cows were collected in 75 to 65 OM and 69 to 62 CM herds. The antibody status regarding BRSV and BoCV was analysed with commercial indirect ELISAs. Herds were classified as positive if at least one individual sample was positive.

Results

The prevalence of positive herds ranged from 73.4% to 82.3% for BRSV and from 76.8% to 85.3% for BoCV among OM and CM herds, over the three sampling occasions. There was no statistically significant difference between OM and CM herds at any sampling occasion. The incidence risk of newly infected herds did not differ statistically between OM and CM herds at any sampling occasion, neither for BRSV nor for BoCV. The incidence of herds turning sero-negative between samplings corresponded to the incidence of newly infected. Bulk tank milk (BTM) samples were also sampled in the herds and analysed. Several herds were negative on individual samples but positive in BTM. Herd-level data on production, health and reproduction were retrieved from VÄXA Sweden and the study herds were representative of the source population.

Conclusion

There was no difference in prevalence of or incidence risk for BRSV or BoCV between Swedish OM and CM herds. Because the incidence of herds becoming seropositive was balanced by herds becoming seronegative it should be possible to lower the prevalence of these two infections among Swedish dairy cattle herds if biosecurity is improved.

Electronic supplementary material

The online version of this article (doi:10.1186/s13028-014-0091-x) contains supplementary material, which is available to authorized users.  相似文献   

Diabetes mellitus in elkhounds is associated with diestrus and pregnancy     

Fall T  Hedhammar A  Wallberg A  Fall N  Ahlgren KM  Hamlin HH  Lindblad-Toh K  Andersson G  Kämpe O 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2010,24(6):1322-1328

Background: Female Elkhounds are shown to be at increased risk for diabetes mellitus, and occurrence of diabetes during pregnancy has been described in several cases. Hypothesis: Onset of diabetes mellitus in Elkhounds is associated with diestrus. Animals: Sixty‐three Elkhounds with diabetes mellitus and 26 healthy controls. Methods: Medical records from 63 Elkhounds with diabetes were reviewed and owners were contacted for follow‐up information. Blood samples from the day of diagnosis were available for 26 dogs. Glucose, fructosamine, C‐peptide, growth hormone (GH), insulin‐like growth factor‐1, progesterone, and glutamate decarboxylase isoform 65‐autoantibodies were analyzed and compared with 26 healthy dogs. Logistic models were used to evaluate the association of clinical variables with the probability of diabetes and with permanent diabetes mellitus after ovariohysterectomy (OHE). Results: All dogs in the study were intact females and 7 dogs (11%) were pregnant at diagnosis. The 1st clinical signs of diabetes mellitus occurred at a median of 30 days (interquartile range [IQR], 3–45) after estrus, and diagnosis was made at a median of 46 days (IQR, 27–62) after estrus. Diabetes was associated with higher concentrations of GH and lower concentrations of progesterone compared with controls matched for time after estrus. Forty‐six percent of dogs that underwent OHE recovered from diabetes with a lower probability of remission in dogs with higher glucose concentrations (odds ratio [OR], 1.2; P= .03) at diagnosis and longer time (weeks) from diagnosis to surgery (OR, 1.5; P= .05). Conclusions: Diabetes mellitus in Elkhounds develops mainly during diestrus and pregnancy. Immediate OHE improves the prognosis for remission of diabetes.  相似文献   

中国部分新育成杂交水稻品种在几内亚适应性鉴定     

叶永印  刘健  Saliou  石金贵  范欢 《山地农业生物学报》2010,29(1):76-80

本研究以几内亚主栽水稻品种为对照,对从中国引进的11个高产、优质、高抗的水稻新组合进行试验筛选。结果表明,筛选出的7个杂交水稻新组合,均表现出生育期短、株高适中、高产、优质、抗病特性。建议几内亚农业部根据不同地区雨季长短进行试验、示范及推广。优质杂交香稻组合内优香18,几农业部已请求协助解决适量种子,以期同时进行多点试验、示范。  相似文献   

Fungal endophytes as promising tools for the management of bean stem maggot Ophiomyia phaseoli on beans Phaseolus vulgaris     

Beritah Mutune  Sunday Ekesi  Saliou Niassy  Viviene Matiru  Christine Bii  Nguya K. Maniania 《Journal of pest science》2016,89(4):993-1001

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Spatial separation of semiochemical Lurem‐TR and entomopathogenic fungi to enhance their compatibility and infectivity in an autoinoculation system for thrips management          下载免费PDF全文

David K Mfuti  Sevgan Subramanian  Rob WHM van Tol  Gerrie L Wiegers  Willem J de Kogel  Saliou Niassy  Hannalene du Plessis  Sunday Ekesi  Nguya K Maniania 《Pest management science》2016,72(1):131-139

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Spatiotemporal variation in airborne sporangia of Phytophthora infestans: characterization and initiatives towards improving potato late blight risk estimation          下载免费PDF全文

M. L. Fall  H. Van der Heyden  L. Brodeur  Y. Leclerc  G. Moreau  O. Carisse 《Plant pathology》2015,64(1):178-190

This study investigated the value of using real‐time monitoring of Phytophthora infestans airborne inoculum as a complement to decision support systems (DSS). The experiment was conducted during the 2010, 2011 and 2012 potato production seasons in two locations in New Brunswick, Canada. Airborne sporangia concentrations (ASC) of P. infestans were monitored using 16 rotating‐arm spore samplers placed 3 m above the ground. The first cases of late blight (2010 and 2011) were detected 6–7 days after the first ASC peak, and all samplers captured their first sporangia within the same week (at 3‐ and 9‐day periods). The cumulative ASC curve and the risk curves from two DSS (PLANT‐Plus and Pameseb Late Blight) had the same shape but different magnitudes. In both locations, the negative binomial distribution fitted the data better than the Poisson distribution, which is indicative of heterogeneity, and based on Taylor's power law, the heterogeneity increased with increasing ASC. Therefore, the present results suggest that spore‐sampling network devices may be a suitable approach for early detection of incoming inoculum and, when combined with DSS, represent a potential aid for targeting the optimal time to apply a disease‐control product. In this context, cumulative ASC can be a counterweight to the DSS risk estimate: a high risk combined with significant ASC will trigger fungicide spraying. Moreover, spore sampling can be used to assess the efficiency of management strategies by means of examining the area under the inoculum progress curve.  相似文献   

Digestibility of solvent-treated Jatropha curcas kernel by broiler chickens in Senegal     

Thierry Daniel Tamsir Nesseim  Abdoulaye Dieng  Guy Mergeai  Saliou Ndiaye  Jean-Luc Hornick 《Tropical animal health and production》2015,47(8):1553-1560

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Effectiveness of conventional and hydrosurgical debridement methods in reducing Staphylococcus aureus inoculation of equine muscle in vitro          下载免费PDF全文

E. M. Skärlina  J. M. Wilmink  N. Fall  D. A. Gorvy 《Equine veterinary journal》2015,47(2):218-222

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Patch-based graphs of landscape connectivity: A guide to construction, analysis and application for conservation   总被引：4，自引：0，他引：4  

Paul Galpern  Micheline Manseau  Andrew Fall 《Biological conservation》2011,(1):44-55

Graph theory has become a popular tool for modelling the functional connectivity of landscapes. We conduct a review of studies that use graph theory to model connectivity among patches of habitat (patch-based graphs), with the intention of identifying typical research questions and their associated graph construction and analysis methods. We identify and examine nine questions of conservation importance that can be answered with these types of graph models, discussing appropriate applications of these questions and presenting a guide for using graph methods to answer them. We also investigate how the connectivity predictions of patch-based graphs have been assessed and emphasize the importance of empirical evaluation. Our findings identify commonality among diverse approaches and methodological gaps with an aim to improve application and to help the integration of graph theory and ecological analysis.  相似文献