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21.
Yamada S Konnai S Imamura S Simuunza M Chembensofu M Chota A Nambota A Onuma M Ohashi K 《Veterinary journal (London, England : 1997)》2009,182(2):352-355
To ascertain the infection rate for tick-borne pathogens in Zambia, an epidemiological survey of Theileria parva, Babesia bigemina and Anaplasma marginale in traditionally managed Sanga cattle was conducted using PCR. Of the 71 native Zambian cattle, 28 (39.4%) were positive for T. parva, 16 (22.5%) for B. bigemina and 34 (47.9%) for A. marginale. The mixed infection rate in cattle was 8.5% (6/71), 16.9% (12/71), 7.0% (5/71) and 2.8% (2/71) for T. parva/B. bigemina, T. parva/A. marginale, B. bigemina/A. marginale and T. parva/B. bigemina/A. marginale, respectively.To predict the risk for transmission of tick-borne pathogens from ticks to cattle, a total of 74 Rhipicephalus appendiculatus ticks were collected from a location where cattle had been found positive for T. parva. Of the ticks collected, 10 (13.5%) were found to be PCR-positive for T. parva. The results suggest that the infection rate for tick-borne pathogens was relatively high in Sanga cattle and that adult R. appendiculatus ticks were highly infected with T. parva. 相似文献
22.
Amos Navon 《Crop Protection》2000,19(8-10):669-676
Bacillus thuringiensis (Bt) has been the leading biopesticide against lepidopterous pests since 1959. In the 1990 s the following developments contributed to increased rational uses of Bt: (1) natural and recombinant Bt products were developed to broaden the insect host range in pest management programs; (2) new formulations based on conventional or genetically engineered encapsulation of the toxins and/or feeding stimulants to increase ingestion and, in turn, the efficacy of the microbe; (3) screening of the interactions of Bt with insect herbivores and plant allelochemicals or natural enemies of the pests, to aid the formulation of biological control strategies; and (4) knowledge and management of insect resistance to Bt. The prospects for Bt insecticides will be described and discussed. 相似文献
23.
Chris Ojiewo Emmanuel Monyo Haile Desmae Ousmane Boukar Clare Mukankusi‐Mugisha Mahendar Thudi Manish K. Pandey Rachit K. Saxena Pooran M. Gaur Sushil K. Chaturvedi Asnake Fikre NPVR Ganga Rao CV SameerKumar Patrick Okori Pasupuleti Janila Jean Claude Rubyogo Chigeza Godfree Essegbemon Akpo Lucky Omoigui Stanley Nkalubo Berhanu Fenta Papias Binagwa Michael Kilango Magdalena Williams Omari Mponda David Okello Mekasha Chichaybelu Amos Miningou Joseph Bationo Dramane Sako Sory Diallo Candidus Echekwu Muhammad Lawan Umar Richard Oteng‐Frimpong Haruna Mohammed Rajeev K. Varshney 《Plant Breeding》2019,138(4):487-499
Legumes are important components of sustainable agricultural production, food, nutrition and income systems of developing countries. In spite of their importance, legume crop production is challenged by a number of biotic (diseases and pests) and abiotic stresses (heat, frost, drought and salinity), edaphic factors (associated with soil nutrient deficits) and policy issues (where less emphasis is put on legumes compared to priority starchy staples). Significant research and development work have been done in the past decade on important grain legumes through collaborative bilateral and multilateral projects as well as the CGIAR Research Program on Grain Legumes (CRP‐GL). Through these initiatives, genomic resources and genomic tools such as draft genome sequence, resequencing data, large‐scale genomewide markers, dense genetic maps, quantitative trait loci (QTLs) and diagnostic markers have been developed for further use in multiple genetic and breeding applications. Also, these mega‐initiatives facilitated release of a number of new varieties and also dissemination of on‐the‐shelf varieties to the farmers. More efforts are needed to enhance genetic gains by reducing the time required in cultivar development through integration of genomics‐assisted breeding approaches and rapid generation advancement. 相似文献
24.
Landscape Ecology - Studying biodiversity in light of increased fragmentation in agroecosystems requires the understanding of scale-dependent and multi-scale determinants of various community... 相似文献
25.
Hampus Eriksson Kim Friedman Moses Amos Ian Bertram Kalo Pakoa Rebecca Fisher Neil Andrew 《Fish and Fisheries》2018,19(2):308-320
Interacting social and ecological processes shape productivity and sustainability of island small‐scale fisheries (SSF). Understanding limits to productivity through historical catches help frame future expectations and management strategies, but SSF are dispersed and unaccounted, so long‐term standardized data are largely absent for such analyses. We analysed 40 years of trade statistics of a SSF product that enter international markets (sea cucumber) from 14 Pacific Island Countries and Territories (PICT) against response variables to test predictors of fishery production: (i) scale, (ii) productivity and (iii) socio‐economics. Combined production in PICT peaked over 20 years ago, driven by exploitation trends in Melanesia that accounted for 90% of all production since 1971. The size of island fisheries (as measured by total exports), and the duration and magnitude of fishery booms were most influenced by ungovernable environmental variables, in particular land area. The large and high islands of Melanesia sustained larger booms over longer periods than atoll nations. We hypothesize that land area is a proxy for land‐based nutrient availability and habitat diversity, and therefore the productivity of the shallow water areas where SSF are operating. PICT need to tailor management based on the intrinsic productivity of shallow inshore habitats: harvests from atoll nations will need to be smaller per unit area than at the high islands. Particularly countries with low productivity fisheries must consider the crucial economic “safety nets” that export SSF make up for dispersed island populations and incorporate them into broader development and island resilience strategies. 相似文献
26.
The effects of photoperiod and water exchange rate on the larvae of gilthead sea bream, Sparus aurata, from hatching to metamorphosis, 60–70 days later, were tested. Survival, growth rate and condition factor were determined with photoperiods of 12 and 24 h, and water exchange rates of 0 and 25%/day.Continuous light supported the highest mean survival (3.25%), with a maximum of 7.8% from hatching to metamorphosis. Growth rate in dry weight was best under continuous light in a water system with no exchange, up to 20 days post-hatching. Highest growth rates of larvae 40–60 days old were obtained in tanks with 25% of their water exchanged daily, along with a 12-h photoperiod. Condition factor was directly correlated with larval age. For the first 30 days after hatching, condition factor was affected by photoperiod and was highest for larvae exposed to continuous light. 相似文献
27.
28.
ABSTRACT Two biocontrol agents, a yeast (Pichia guilermondii) and a bacterium (Bacillus mycoides), were tested separately and together for suppression of Botrytis cinerea on strawberry leaves. The aims of the research were to determine whether the use of their combination would broaden the environmental conditions under which biological control is effective, and to test the hypothesis that it would reduce the variability of control efficacy under diverse conditions. Applied separately, the biocontrol agents significantly inhibited spore germination, lesion formation, and lesion development at most temperatures, relative humidities, and spray-timing combinations (temperatures: 10, 15, 20, 23, 25, and 30 degrees C; relative humidities: 78, 85, 96, and 100%; and spray-timings: 0, 4, and 7 days before inoculation). However, control efficacy was highly variable, and under certain combinations it was not adequate. Control efficacy achieved by the biocontrol agents applied separately ranged between 38 and 98% (mean 74%) and the coefficient of variation ranged from 9.7 to 75%. The mixture of Bacillus mycoides and Pichia guilermondii suppressed Botrytis cinerea effectively (80 to 99.8% control) under all conditions, and the coefficients of variation were as low as 0.4 to 9% in all cases. Thus, application of both biocontrol agents resulted in better suppression of Botrytis cinerea, and also reduced the variability of disease control. Application of more than one biocontrol agent is suggested as a reliable means of reducing the variability and increasing the reliability of biological control. 相似文献
29.
Tal Kanety Amos Naor Ami Gips Uri Dicken J. Hugo Lemcoff Shabtai Cohen 《Irrigation Science》2014,32(1):1-13
A 3-year irrigation trial provided basic information on the response of persimmon (Diospyros kaki cv. Triumph) water use and development to irrigation levels. Constant experimental factors applied to recommended “baseline” crop factors resulted in ratios of irrigation (I) to FAO56 reference crop evapotranspiration (ET0) ranging from 0.35 to 1.14. Vegetative and reproductive growth, sap flow, stem water potential (SWP), and local climate were monitored. An overall increase in yield and vegetative growth in response to irrigation was found, which suggests a potential yield increase for higher irrigation levels (40 tons/ha for annual irrigation of 1,000 mm). At high irrigation, the yield response curve levelled off and the marginal contribution of additional water declined. The up to threefold increase in number of fruits with irrigation, with no influence on natural abscission, suggests that differences in fruit quantities stem from response to irrigation at the earlier growth stages. Mean fruit size and fruit quality, as indicated by the ratio of rejected fruit, increased with irrigation up to I/ET0 of ~0.8. Relative yield increased linearly with relative transpiration. However, post-harvest quality was not influenced. SWP, sap flow, and non-transpirable water fractions indicated that the seasonal irrigation tables were not well tuned. Initial adjustments were made during the final season of the experiment and a new table was developed based on our results. The new table should be a basis for further trials. 相似文献
30.
Human histocompatibility locus HL-A 总被引:2,自引:0,他引:2
D B Amos 《Science (New York, N.Y.)》1968,159(815):659-660