Impact of weather variables and season on sporulation of Phytophthora pluvialis and Phytophthora kernoviae     

Stuart Fraser  Mireia Gomez‐Gallego  Judy Gardner  Lindsay S. Bulman  Sandra Denman  Nari M. Williams 《Forest Pathology》2020,50(2)

Phytophthora pluvialis and Phytophthora kernoviae are the causal agents of important needle diseases on Pinus radiata in New Zealand. Little is known about the epidemiology of the diseases, making the development of control strategies challenging. To investigate the seasonality and climatic drivers of sporulation, inoculum traps, consisting of pine fascicles floating on water in plastic containers, were exchanged fortnightly at five sites in P. radiata plantations between February 2012 and December 2014. Sections of needle baits were plated onto selective media and growth of Phytophthora pluvialis and P. kernoviae recorded. To explore the generalizability of these data, they were compared to detection data for both pathogens from the New Zealand Forest Health Database (NZFHDB). Further, equivalent analyses on infection of Rhododendron ponticum by P. kernoviae in Cornwall, UK allowed the comparison of the epidemiology of P. kernoviae across different host systems and environments. In New Zealand, inoculum of P. pluvialis and P. kernoviae was detected between January–December and March–November, respectively. Inoculum of both species peaked in abundance in late winter. The probability of detecting P. pluvialis and P. kernoviae was greater at lower temperatures, while the probability of detecting P. pluvialis also increased during periods of wet weather. Similar patterns were observed in NZFHDB data. However, the seasonal pattern of infection by P. kernoviae in the UK was the opposite of that seen for sporulation in New Zealand. Phytophthora kernoviae was likely limited by warmer and drier summers in New Zealand, but by colder winter weather in the UK. These results emphasize the importance of considering both environmental drivers and thresholds in improving our understanding of pathogen epidemiology.  相似文献   

Climate change will affect the ability of forest management to reduce gaps between current and presettlement forest composition in southeastern Canada     

Boulanger  Yan  Arseneault  Dominique  Boucher  Yan  Gauthier  Sylvie  Cyr  Dominic  Taylor  Anthony R.  Price  David T.  Dupuis  Sébastien 《Landscape Ecology》2019,34(1):159-174

Landscape Ecology - Forest landscapes at the boreal–temperate ecotone have been extensively altered. Reducing the gap between current and presettlement forest conditions through...  相似文献   

Development of colchicine‐induced tetraploid St. Augustinegrass (Stenotaphrum secundatum) lines     

Esdras M. Carbajal  M. Carolina Zuleta  Luellen Swayzer  Brian M. Schwartz  Maria Carolina Chavarro  A. Carolina Ballen‐Taborda  Susana R. Milla‐Lewis 《Plant Breeding》2019,138(6):958-966

St. Augustinegrass is well suited for lawns and commercial landscapes. While many genotypes are cross‐fertile, all cultivars are propagated vegetatively in sod production. To ensure varietal purity, development of sterile triploid hybrids by crossing tetraploid and diploid genotypes has been successfully used in other warm‐season turfgrasses. Applying this model in St. Augustinegrass would be beneficial to sod producers and turf managers who require purity for certification and uniformity for performance, respectively. This study was conducted to develop colchicine‐induced tetraploid lines of St. Augustinegrass. Seeds of cultivar ‘Raleigh’ were treated with four colchicine concentrations at four exposure times. A non‐treated control was included among the treatments. Seedlings that germinated were screened for genome size changes using flow cytometry. Line DSA 13005 and two progeny lines derived through selfing, DSA 16001 and DSA 16016, were corroborated as tetraploids (2n = 4x = 36) through chromosome counts. These lines will be used in future breeding efforts to attempt development of sterile triploid cultivars of St. Augustinegrass.  相似文献   

Upper body movement analysis of multiple limb asymmetry in 367 clinically lame horses     

Suphannika Phutthachalee  Kathrin Mählmann  Suvaluk Seesupa  Christoph Lischer 《Equine veterinary journal》2021,53(4):701-709

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Proteomic profiles during adventitious rooting of Eucalyptus species relevant to the cellulose industry     

de Almeida  Márcia Rodrigues  Schwambach  Joséli  Silveira  Vanildo  Heringer  Angelo Schuabb  Fett  Janette Palma  Fett-Neto  Arthur G. 《New Forests》2020,51(2):213-241

New Forests - Adventitious rooting (AR) is an obligatory step for vegetative propagation of commercial woody species. Paper industries have interest in Eucalyptus globulus Labill and its hybrids...  相似文献   

Effects of brodifacoum and diphacinone exposure on four species of reptiles: tissue residue levels and survivorship     

Richard E Mauldin  Gary W Witmer  Susan A Shriner  Rachael S Moulton  Katherine E Horak 《Pest management science》2020,76(5):1958-1966

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Effects of Feeding Frequency on Apparent Energy and Nutrient Digestibility/Availability of Channel Catfish,Ictalurus punctatus,Reared at Optimal and Suboptimal Temperatures          下载免费PDF全文

Menghe H. Li  Penelope M. Lucas 《Journal of the World Aquaculture Society》2017,48(1):132-136

This study examined the effects of feeding frequency (daily versus every other day [EOD]) on nutrient digestibility/availability of channel catfish, Ictalurus punctatus, reared at optimal (30 C) and suboptimal (24 C) temperatures. A 28% protein practical diet was used as the test diet, and chromic oxide was used at 0.75% of the diet as a maker. Twenty channel catfish of a mean weight of 141 g/fish were stocked into 12 flow‐through aquaria (110 L). Fish were fed daily or EOD to apparent satiation for 7 d before fecal samples were collected by the dissection method. Fish fed EOD to apparent satiation consumed more diet on days fed than those fed daily, and fish reared at 30 C consumed more diet than those reared at 24 C. Neither feeding frequency nor water temperature significantly affected apparent digestibility coefficients for energy and protein and apparent availability coefficients for total amino acids. Results show no advantage by feeding EOD over feeding daily on nutrient digestibility and diet utilization efficiency.  相似文献   

The efficiency of nitrogen in cattle manures when applied to a double‐annual forage cropping system          下载免费PDF全文

B. Perramon  À. D. Bosch‐Serra  F. Domingo‐Olivé  J. Boixadera 《Grass and Forage Science》2017,72(4):676-690

The use of cattle manure (CM) for fertilization presents challenges for optimizing nitrogen (N) use. Our work aimed to assess N efficiencies, in a 6‐year experiment with three biennial rotations of four crops: oat–sorghum (first year) and ryegrass–maize (second year) in a rainfed humid Mediterranean area of Spain. Fertilization treatments included the following: control (no N), 250 kg mineral N ha^?1 year^?1 (250MN), three CM rates (supplying 170, 250 and 500 kg N ha^?1 year^?1) and four treatments where the two lowest CM rates were complemented with either 80 or 160 kg mineral N ha^?1 year^?1. Treatments were distributed randomly in each of three blocks. Maximum dry‐matter yield (~44–49 t ha^?1 rotation^?1) was achieved in the third rotation, and only the control and the 170CM yielded significantly less. Within the limitations of the EU Nitrate Directive, the N steady state supply of 170CM always requires a complement of mineral N (80 kg N ha^?1) to maximize N agronomic efficiency. The maximum N‐fertilizer replacement value (250CM vs. 250MN) was 0·67, without significant differences between the two treatments in other N‐related efficiency indexes, which indicates that plants took advantage of residual‐N effects. Nitrogen losses by leaching in the 250CM treatment were around 5–7% of the N applied. This reinforces the sustainability of manure recycling in long cropping seasons.  相似文献   

Evaluation of mechanical properties of jute/glass/carbon fibers reinforced hybrid composites     

M. A. Abd El-baky 《Fibers and Polymers》2017,18(12):2417-2432

A study on the tensile and flexural properties of jute-glass-carbon fibers reinforced epoxy hybrid composites in inter-ply configuration is presented in this paper. Test specimens were manufactured by hand lay-up process and their tensile and flexural properties were obtained. The effects of the hybridization, different fibers content and plies stacking sequence on the mechanical properties of the tested hybrid composites were investigated. Two-parameter Weibull distribution function was used to statistically analyze the experimental results. The failure probability graphs for the tested composites were drawn. These graphs are important tools for helping the designers to understand and choose the suitable material for the required design and development. Results showed that the hybridization process can potentially improve the tensile and flexural properties of jute reinforced composite. The flexural strength decreases when partial laminas from a carbon/epoxy laminate are replaced by glass/epoxy or jute/epoxy laminas. Also, it is realized that incorporating high strength fibers to the outer layers of the composite leads to higher flexural resistance, whilst the order of the layers doesn’t affect the tensile properties.  相似文献   

Silage and total mixed ration hygienic quality on commercial farms: implications for animal production          下载免费PDF全文

T. Cogan  R. Hawkey  E. Higgie  M. R. F. Lee  E. Mee  D. Parfitt  J. Raj  S. Roderick  N. Walker  P. Ward  J. M. Wilkinson 《Grass and Forage Science》2017,72(4):601-613

Implications of silage hygienic quality for animal production were investigated on forty‐five dairy farms in South West England. Samples of grass and maize silages and of total mixed rations (TMR) were obtained together with information on silage technology, herd size and animal production. Samples were analysed for mycotoxins, bacteria, yeasts, moulds and chemical composition. Thirteen mycotoxins were assayed, but none were detected in the samples of grass silage. However, mycotoxins were found in 0·9 of all maize and other silage samples, with deoxynivalenol and zearalenone predominating. There was no relationship between total mycotoxin concentration and mean lactation milk yield per cow. Enterobacteria counts tended to be higher in maize silage than in grass silage and higher still in TMR – a cause for concern. There were no relationships between mould counts and mycotoxin concentrations in silages, implying that mycotoxins may have been produced in the field pre‐ensiling.  相似文献