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1
Soleimani, M. J., i M. L. Deadman. "Factors Affecting the Levels of Eyespot and Fusarium Foot-Rot on Winter Wheat cv. Hereward in Cereal Monocrops and Wheat Clover Bicrops". Journal of Agricultural and Marine Sciences [JAMS] 4, nr 2 (1.06.1999): 7. http://dx.doi.org/10.24200/jams.vol4iss2pp7-12.
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Various factors influencing the amount of disease on the stem-base of wheat, when grown as a component of a bicrop, with white clover, are described. The amount of crop debris on the soil surface remained higher in monocrop than bicropped plots. Furthermore, the rate of debris decay was faster in bicrops than in monocrops. Population levels of P. herpotrichoides and Fusarium spp. were higher on debris within bicrops than on debris within monocrop plots. However, because debris decomposition was more rapid in bierops, inoculum availability was of shorter duration in bicrops than monocrop plots. ln soil, populations of P. herpotrichmoides were greater in bicropped plots than in monocrops, although no significant differences were observed for Fusarium spp. population levels. Pathogen cross-infection between bicrop components and changes in microclimate within crop canopies were shown to occur, and isolates of Fusarium from clover were shown to induce significant levels of disease on cereal seedlings. The effects of each of these factors on disease development are discussed in relation to previous reports of disease levels in the field.
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Limonta, Lidia, Matteo Carlo Morosini i Daria Patrizia Locatelli. "Development of Rhyzopertha dominica (F.) (Coleoptera Bostrichidae) on durum wheat kernels and semolina". Journal of Entomological and Acarological Research 43, nr 1 (30.04.2011): 33. http://dx.doi.org/10.4081/jear.2011.33.
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he time necessary to larvae of <em>Rhyzopertha dominica</em> to drill kernels with or without dusts (semolina or debris from adults), and the possibility of development on semolina were evaluated. T ests were carried out on durum wheat kernels (<em>Triticum durum</em> Desfontaines), debris deriving from rearing, and semolina. Development was observed also on 0.5 and 6 mm of semolina and of debris. T hirty replicates were carried out for each test. The number of first instar larvae, that successfully drill sound kernels within 10 days, was higher by adding semolina or debris. When only kernels were provided, the time needed to larvae to drill increased. Development and the number of emerging adults were not significantly influenced by the addition of semolina to the kernels. Larvae couldn’t develop on 0.5 mm, while an equal number of individuals completed the development to adult in 6 mm of semolina as in the tests with kernels. When development was on debris, a lower number of emerged adults was observed.
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Del Ponte, Emerson M., Denis A. Shah i Gary C. Bergstrom. "Spatial Patterns of Fusarium Head Blight in New York Wheat Fields Suggest Role of Airborne Inoculum". Plant Health Progress 4, nr 1 (styczeń 2003): 6. http://dx.doi.org/10.1094/php-2003-0418-01-rs.
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The spatial pattern of Fusarium head blight (FHB) incidence was studied in 70 winter wheat fields in New York over a period of 3 years. Incidence of FHB was randomly distributed among 60 sampling areas in 64 of the 70 fields. Fields with random FHB ranged from 0.05 to 23% in average incidence of FHB and followed bean, cabbage, corn, oat, pea, sorghum, and soybean. There was strong evidence of aggregation in FHB only in three fields that had large concentrations of corn debris. Many fields had small, scattered fragments of corn debris in evidence from a corn crop two or more years prior to wheat. The lack of aggregation in FHB and low incidences of FHB in these fields suggests that weathered corn debris contributed relatively little within-field inoculum for FHB. Based on the predominantly random patterns of FHB, disease in rotational wheat fields of New York appears to be initiated primarily by deposition of spores from diffuse atmospheric populations of G. zeae. We hypothesize that these airborne spores may originate largely from inoculum sources external to wheat fields. Over-wintered corn residue, especially from the preceding crop season, on the soil surface is the most likely potential source of regional atmospheric inoculum for FHB in New York. Accepted for publication 10 March 2003. Published 18 April 2003.
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Blum, Udo, Larry D. King, Tom M. Gerig, Mary E. Lehman i Arch D. Worsham. "Effects of clover and small grain cover crops and tillage techniques on seedling emergence of some dicotyledonous weed species". American Journal of Alternative Agriculture 12, nr 4 (grudzień 1997): 146–61. http://dx.doi.org/10.1017/s0889189300007487.
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AbstractWe monitored emergence of morning-glory, pigweed, and prickly sida from seeded populations in no-till plots with no debris (reference plots) or with crimson clover, subterranean clover, rye, or wheat debris. Cover crops were either desiccated by glyphosate or mowed and tilled into the soil. Debris levels, soil temperature, moisture, pH, nitrate, total phenolic acid and compaction were monitored during May to August in both 1992 and 1993. Seedling emergence for all three weed species ranged from <1 to 16% of seeds sown. Surface debris treatments delayed weed seedling emergence compared with the reference plots. Rye and wheat debris consistently suppressed weed emergence; in contrast, the effects of clover debris on weed emergence ranged from suppression to stimulation. Gfyphosate application resulted in a longer delay and greater suppression of seedling emergence in May than in April. In 1993, plots in which living biomass was tilled into the soil were also included and monitored. Weed seedling emergence was stimulated when living biomass was incorporated into the soil. Covariate, correlation and principle component analyses did not identify significant relationships between weed seedling emergence and soil physical and chemical characteristics (e.g., total phenolic acid, nitrate, moisture, temperature). We hypothesize that the observed initial delay of the weed seedling emergence for all three species was likely due to low initial soil moisture. The subsequent rapid recovery of seedling emergence of morning-glory and pigweed but notprickfy sida in the clover compared with the small grain debris plots was likely due to variation in soil allelopathic agents or nitrate-N levels. The stimulation of weed seedling emergence when living biomass was incorporated into the soil was likely caused by an increase in “safe” germination sites coupled with the absence of a zone of inhibition resulting from tillage.
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Whelan, Ernest D. P., i E. G. Kokko. "Scanning electron microscopy of chromosomes of common wheat". Genome 35, nr 1 (1.02.1992): 166–69. http://dx.doi.org/10.1139/g92-027.
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The higher magnifications and resolution possible with scanning electron microscopy can provide more detailed information on chromosome morphology than light microscopy. However, overlying cell debris can obscure surface details. A method is described whereby standard organic acid–alcohol fixatives and slightly modified techniques of routine plant chromosome squash preparations can be used to provide samples of mitotic and meiotic chromosomes of wheat suitable for examination by scanning electron microscopy.Key words: scanning electron microscopy, light microscopy, wheat, chromosomes.
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Keller, Melissa D., Katrina D. Waxman, Gary C. Bergstrom i David G. Schmale. "Local Distance of Wheat Spike Infection by Released Clones of Gibberella zeae Disseminated from Infested Corn Residue". Plant Disease 94, nr 9 (wrzesień 2010): 1151–55. http://dx.doi.org/10.1094/pdis-94-9-1151.
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Knowledge of the movement of Gibberella zeae (Fusarium graminearum) from a local source of inoculum in infested cereal debris is critical to the management of Fusarium head blight (FHB) of wheat. Previous spatial dissemination and infection studies were unable to completely distinguish the contributions of released inocula from those of background inocula. Clones of G. zeae were released and recaptured in five wheat fields in New York and Virginia in 2007 and 2008. Amplified fragment length polymorphisms were used to track and unambiguously identify the released clones in heterogeneous populations of the fungus recovered from infected wheat spikes collected at 0, 3, 6, and ≥24 m from small-area sources of infested corn residues. The percent recovery of the released clones decreased significantly at fairly short distances from the inoculum sources. Isolates of G. zeae recovered at 0, 3, 6, and ≥24 m from the center of source areas shared 65, 19, 13, and 5% of the genotypes of the released clones, respectively. More importantly, the incidence of spike infection attributable to released clones averaged 15, 2, 1, and <1% at 0, 3, 6, and ≥24 m from source areas, respectively. Spike infection attributable to released clones decreased an average of 90% between 3 and 6 m from area sources of inoculum, and the spike infection potential of inocula dispersed at this range did not differ significantly from background sources. Our data suggest that FHB field experiments including a cereal debris variable should incorporate debris-free borders and interplots of at least 3 m and preferably 6 m to avoid significant interplot interference from spores originating from within-field debris.
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Baird, R. E., B. G. Mullinix, A. B. Peery i M. L. Lang. "Diversity and Longevity of the Soybean Debris Mycobiota in a No-Tillage System". Plant Disease 81, nr 5 (maj 1997): 530–34. http://dx.doi.org/10.1094/pdis.1997.81.5.530.
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The survival of the mycobiota on pod and stem debris of soybean produced in a no-tillage system with cover crops of alfalfa, canola, rye, or wheat or with no cover was studied during 1994 and 1995. Fiberglass mesh bags containing pods and stems were assayed every 28 to 31 days to determine the isolation frequency of fungi. Over 90% of the 11,906 isolates obtained were members of the Deuteromycotina. The most common genera isolated were Alternaria, Cercos-pora, Colletotrichum, Epicoccum, Fusarium, and Phoma. Alternaria spp. had the greatest isolation frequencies and constituted 40% of the total cultures. Numbers of total fungi (all fungi isolated) on sampling dates in 1994 were similar to the totals in 1995. In May 1994, the mean isolation rates for many of the fungal species were significantly lower (P = 0.05) in several of the cover crops, but no consistent pattern could be determined. Common soybean pathogens isolated included Colletotrichum spp., Diaporthe spp., and Cercospora kikuchii. Fusarium graminearum, which is responsible for several diseases of maize and wheat, was commonly isolated during this study. Of the Diaporthe spp. (anamorph Phomopsis spp.), 87% were identified as D. phaseolorum var. sojae. Colletotrichum spp. were identified as C. truncatum in 85% of the isolates, C. destructivum (teleomorph Glomerella glycines) in 12%, and both species in 3%. Cercospora kikuchii was more commonly isolated from pods than from stem tissue, and Colletotrichum spp. occurred more frequently on stems. Isolation frequencies of Diaporthe spp. were greater in May of both years than in the preceding months. These results show that no-tillage soybean debris harbors numerous fungi pathogenic to soybean, and producers who grow soybeans continuously may find more disease in this crop and lower yields. Fungi that attack crops such as maize and wheat were commonly isolated from soybean debris in both years, and a no-tillage rotation which includes maize or wheat could result in increased disease in these crops. Isolation frequencies of the fungi from cover crops varied with the sampling date, but no consistent patterns could be determined for a particular cover crop or fungal species. This is the first detailed study of survival rates of soybean, maize, and wheat pathogens that overwinter on soybean debris in a no-tillage system.
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Wakimoto, Roger M., Zachary Wienhoff, Howard B. Bluestein i Dylan Reif. "The Dodge City Tornadoes on 24 May 2016: Damage Survey, Photogrammetric Analysis Combined with Mobile Polarimetric Radar Data". Monthly Weather Review 146, nr 11 (26.10.2018): 3735–71. http://dx.doi.org/10.1175/mwr-d-18-0125.1.
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Abstract Polarimetric measurements recorded by a mobile X-band radar are combined with photographs of the Dodge City, Kansas, tornado to quantitatively document the evolving debris cloud. An inner annulus or tube of high radar reflectivity encircled the tornado at low levels. A column of low cross-correlation coefficient ρhv was centered on the funnel cloud during the early stage of the tornado’s life cycle. In addition, two areas of low ρhv were located near the inner annulus of high radar reflectivity and were hypothesized to be regions of high debris loading that have been reproduced in simulations of lofted debris. Another column of low ρhv was a result of strong wind speeds that were progressively lofting small debris and dust as inflow rotated around and within the weak echo notch of the hook echo. A column of negative differential reflectivity ZDR was also centered on the tornado and was hypothesized to result from common debris alignment. The polarimetric structure undergoes a dramatic transition when the debris cloud was prominent and enveloped most of the funnel cloud. The weak echo column (WEC) began to fill at lower levels as large amounts of debris were lofted into the circulation. The axis of minimum ρhv shifted to a radius just beyond the funnel cloud. A column of positive ZDR was collocated with the funnel surrounded by negative ZDR. The negative ZDR and low ρhv within the debris cloud were likely the result of some common debris alignment from wheat stems. The positive ZDR within the funnel signified the presence of a few hydrometeors.
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Cowger, Christina, i Hilda Victoria Silva-Rojas. "Frequency of Phaeosphaeria nodorum, the Sexual Stage of Stagonospora nodorum, on Winter Wheat in North Carolina". Phytopathology® 96, nr 8 (sierpień 2006): 860–66. http://dx.doi.org/10.1094/phyto-96-0860.
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Ascocarps of Phaeosphaeria nodorum, which causes Stagonospora nodorum blotch (SNB) of wheat, have not been found by others in the eastern United States despite extensive searches. We sampled tissues from living wheat plants or wheat debris in Kinston, NC, each month except June from May to October 2003. Additional wheat samples were gathered in Kinston, Salisbury, and Plymouth, NC, in 2004 and 2005. For the 3 years, in all, 2,781 fruiting bodies were dissected from the wheat tissues and examined microscopically. Fruiting bodies were tallied as P. nodorum pycnidia or ascocarps, “unknown” (not containing spores, potentially P. nodorum or other fungi), or “other fungi.” In the 2003 sample, asco-carps of P. nodorum were present each month after May at a frequency of 0.8 to 5.4%, and comprised a significantly higher percentage of fruiting bodies from wheat spikes than of those from lower stems and leaves. Ascocarps also were found at frequencies <10% in some wheat debris samples from 2004 and 2005. Analysis of the nucleotide sequences of internally transcribed spacer regions of 18 genetically distinct North Carolina isolates from 2003 suggested that all were P. nodorum, not the morphologically similar P. avenaria f. sp. triticea. Neither the 18 isolates from 2003 nor a set of 77 isolates derived from 2004 Kinston leaf samples gave reason to suspect a mating-type imbalance in the larger P. nodorum population (P ≥ 0.4). We conclude that, in North Carolina, sexual reproduction plays a role in initiation of SNB epidemics and the creation of adaptively useful genetic variability, although its relative importance in structuring this population is uncertain.
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Cowger, Christina, Randy Weisz, Joseph M. Anderson i J. Ray Horton. "Maize Debris Increases Barley Yellow Dwarf Virus Severity in North Carolina Winter Wheat". Agronomy Journal 102, nr 2 (marzec 2010): 688–95. http://dx.doi.org/10.2134/agronj2009.0357.
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Neate, S. M. "Plant debris in soil as a source of inoculum of Rhizoctonia in wheat". Transactions of the British Mycological Society 88, nr 2 (marzec 1987): 157–62. http://dx.doi.org/10.1016/s0007-1536(87)80210-3.
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JALALUDDIN, M., i J. F. JENKYN. "Effects of wheat crop debris on the sporulation and survival of Pseudocercosporella herpotrichoides". Plant Pathology 45, nr 6 (grudzień 1996): 1052–64. http://dx.doi.org/10.1046/j.1365-3059.1996.d01-194.x.
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Beck-Broichsitter, Steffen, Saskia Ruth, Richard Schröder, Heiner Fleige, Horst H. Gerke i Rainer Horn. "Simultaneous determination of wettability and shrinkage in an organic residue amended loamy topsoil". Journal of Hydrology and Hydromechanics 68, nr 2 (1.06.2020): 111–18. http://dx.doi.org/10.2478/johh-2020-0007.
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AbstractIn agricultural land use, organic residues such as compost, digestate, and sewage sludge are discussed as costeffective soil conditioner that may improve the water holding capacity and crop available soil moisture. The objective of this study is to determine the effect of application of digestates with different compositions in maize, sugar beet and winter wheat, compost of shrub debris and sewage sludge on shrinkage behaviour and contact angle of till-derived loamy topsoil of a Haplic Luvisol under agricultural use. Novelty is the simultaneous determination of contact angle and shrinkage of soils amended with digestates composed of different composition in maize, sugar beet and winter wheat, compost of shrub debris and sewage sludge. The results suggest that the application of organic residues impacts the air capacity, while the contact angles remained in the subcritical range between > 0° and < 90°. The relationship between CA values and moisture ratios, ϑ, during proportional shrinkage was positive and linear (r2 of 0.98) and negative during residual- and zero-shrinkage (r2 of 0.93).
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SCOTT, P. R., F. R. SANDERSON i P. W. BENEDIKZ. "Occurrence of Mycosphaerella graminicola, teleomorph of Septoria tritici, on wheat debris in the UK". Plant Pathology 37, nr 2 (czerwiec 1988): 285–90. http://dx.doi.org/10.1111/j.1365-3059.1988.tb02076.x.
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Van_Toor, R. F., S. L. Bithell, S. F. Chng, A. McKay i M. G. Cromey. "Impact of cereal rotation strategies on soil inoculum concentrations and wheat takeall". New Zealand Plant Protection 66 (8.01.2013): 204–13. http://dx.doi.org/10.30843/nzpp.2013.66.5541.
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The fungus Gaeumannomyces graminis var tritici (Ggt) causes takeall in cereals and survives saprophytically on crop debris during the intercrop period Commercial wheat fields with different crop rotations on 10 farms in the South Island of New Zealand were monitored over 6 years for changes in Ggt inoculum concentrations and takeall severity Takeall severity in wheat varied greatly among crop rotations across the farms with aboveground symptoms seldom visible on some farms and common on others Takeall severity was reduced by maintaining a low frequency of host crops in the rotation Ggt was detected in soil from all farms Soil inoculum concentrations were reduced proportional to the length of nonhost break crops While barley triticale and rye are less susceptible than wheat to takeall they can lead to high postharvest inoculum concentrations
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Dillé, John E., Douglas C. Bittel, Kathleen Ross i J. Perry Gustafson. "Preparing plant chromosomes for scanning electron microscopy". Genome 33, nr 3 (1.06.1990): 333–39. http://dx.doi.org/10.1139/g90-052.
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The scanning electron microscope may be useful in the analysis of plant chromosomes treated with in situ hybridization, especially when the probes and (or) chromosomes are near or beyond the resolution of the light microscope. Usual methods of plant chromosome preparation are unsuitable for scanning electron microscope observation as a result of cellular debris, which also interferes with probe hybridization. A method is described whereby protoplasts are obtained from fixed root tips by enzymatic digestion and applied to slides in a manner that produces little or no cellular debris overlying the chromosomes. The slides were examined by scanning electron microscopy and light microscopy after C-banding and in situ hybridization with a rye nucleolus organizer region spacer probe. This technique, which allows for scanning electron microscope visualization of bands and probes not easily identified with light microscopy, should prove useful in the physical mapping of low copy number or unique DNA sequences.Key words: protoplasts, rice, wheat, rye, physical maps, in situ hybridization.
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Luongo, Laura, Massimo Galli, Luciana Corazza, Ellis Meekes, Lia De Haas, Carin Lombaers Van Der Plas i Jürgen Köhl. "Potential of fungal antagonists for biocontrol ofFusariumspp. in wheat and maize through competition in crop debris". Biocontrol Science and Technology 15, nr 3 (maj 2005): 229–42. http://dx.doi.org/10.1080/09583150400016852.
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Wienhoff, Zachary B., Howard B. Bluestein, Dylan W. Reif, Roger M. Wakimoto, Louis J. Wicker i James M. Kurdzo. "Analysis of Debris Signature Characteristics and Evolution in the 24 May 2016 Dodge City, Kansas, Tornadoes". Monthly Weather Review 148, nr 12 (grudzień 2020): 5063–86. http://dx.doi.org/10.1175/mwr-d-20-0162.1.
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AbstractOn 24 May 2016, a supercell that produced 13 tornadoes near Dodge City, Kansas, was documented by a rapid-scanning, X-band, polarimetric, Doppler radar (RaXPol). The anomalous nature of this storm, particularly the significant deviations in storm motion from the mean flow and number of tornadoes produced, is examined and discussed. RaXPol observed nine tornadoes with peak radar-derived intensities (ΔVmax) and durations ranging from weak (~60 m s−1) and short lived (<30 s) to intense (>150 m s−1) and long lived (>25 min). This case builds on previous studies of tornado debris signature (TDS) evolution with continuous near-surface sampling of multiple strong tornadoes. The TDS sizes increased as the tornadoes intensified but lacked direct correspondence to tornado intensity otherwise. The most significant growth of the TDS in both cases was linked to two substantial rear-flank-downdraft surges and subsequent debris ejections, resulting in growth of the TDSs to more than 3 times their original sizes. The TDS was also observed to continue its growth as the tornadoes decayed and lofted debris fell back to the surface. The TDS size and polarimetric composition were also found to correspond closely to the underlying surface cover, which resulted in reductions in ZDR in wheat fields and growth of the TDS in terraced dirt fields as a result of ground scouring. TDS growth with respect to tornado vortex tilt is also discussed.
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Klem, K., M. Váňová, J. Hajšlová, K. Lancová i M. Sehnalová. "A neural network model for prediction of deoxynivalenol content in wheat grain based on weather data and preceding crop". Plant, Soil and Environment 53, No. 10 (7.01.2008): 421–29. http://dx.doi.org/10.17221/2200-pse.
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Deoxynivalenol (DON) is the most prevalent Fusarium toxin in Czech wheat samples and therefore forecasting this mycotoxin is a potentially useful tool to prevent it from entering into food chain. The data about DON content in wheat grain, weather conditions during the growing season and cultivation practices from two field experiments conducted in 2002–2005 were used for the development of neural network model designed for DON content prediction. The winning neural network is based on five input variables: a categorial variable – preceding crop, and continuous variables – average April temperature, sum of April precipitation, average temperature 5 days prior to anthesis, sum of precipitation 5 days prior to anthesis. The most important input parameters are the preceding crop and sum of precipitation 5 days prior to anthesis. The weather conditions in April, which are important for inoculum formation on crop debris are also of important contribution to the model. The weather conditions during May and 5 days after anthesis play only an insignificant role for the DON content in grain. The effect of soil cultivation was found inferior for model function as well. The correlation between observed and predicted data using the neural network model reached the coefficient <i>R</i><sup>2</sup> = 0.87.
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Fernandez, M. R., i Y. Chen. "Pathogenicity of Fusarium Species on Different Plant Parts of Spring Wheat Under Controlled Conditions". Plant Disease 89, nr 2 (luty 2005): 164–69. http://dx.doi.org/10.1094/pd-89-0164.
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Most of the Fusarium species responsible for Fusarium head blight of wheat in Saskatchewan, Canada, have also been isolated from discolored subcrown internodes/crowns of wheat. It was therefore of interest to compare the susceptibility of heads and ground/underground tissue of wheat to isolates of Fusarium species from different sources. Controlled-environment pathogenicity tests were conducted on heads, seeds, and seedlings of spring wheat. Overall, F. culmorum and F. graminearum were the most pathogenic species, although the former was more pathogenic than the latter. F. equiseti and F. poae were the least pathogenic species, whereas F. avenaceum had intermediate pathogenicity in the head and seed tests, but low pathogenicity in the seedling test. There was a similar pathogenicity among isolates of each Fusarium species from different sources to heads and ground/underground plant parts, indicating a lack of adaptation of these isolates. Our observations suggest that Fusarium inoculum on or in infected seed or plant debris might infect plants at or below soil level, which could then become a source of inoculum for infection of heads in the following season(s). Survival of fungal inoculum in underground plant parts might be important during dry conditions.
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Jenkyn, J. F., R. J. Gutteridge, G. L. Bateman i M. Jalaluddin. "Effects of crop debris and cultivations on the development of eyespot of wheat caused by Oculimacula spp." Annals of Applied Biology 156, nr 3 (20.04.2010): 387–99. http://dx.doi.org/10.1111/j.1744-7348.2010.00396.x.
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Turzhanova, Ainur, Oxana N. Khapilina, Asem Tumenbayeva, Vladislav Shevtsov, Olesya Raiser i Ruslan Kalendar. "Genetic diversity of Alternaria species associated with black point in wheat grains". PeerJ 8 (5.05.2020): e9097. http://dx.doi.org/10.7717/peerj.9097.
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The genus Alternaria is a widely distributed major plant pathogen that can act as a saprophyte in plant debris. Fungi of this genus frequently infect cereal crops and cause such diseases as black point and wheat leaf blight, which decrease the yield and quality of cereal products. A total of 25 Alternaria sp. isolates were collected from germ grains of various wheat cultivars from different geographic regions in Kazakhstan. We investigated the genetic relationships of the main Alternaria species related to black point disease of wheat in Kazakhstan, using the inter-primer binding site (iPBS) DNA profiling technique. We used 25 retrotransposon-based iPBS primers to identify the differences among and within Alternaria species populations, and analyzed the variation using clustering (UPGMA) and statistical approaches (AMOVA). Isolates of Alternaria species clustered into two main genetic groups, with species of A.alternata and A.tennuissima forming one cluster, and isolates of A. infectoria forming another. The genetic diversity found using retrotransposon profiles was strongly correlated with geographic data. Overall, the iPBS fingerprinting technique is highly informative and useful for the evaluation of genetic diversity and relationships of Alternaria species.
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SAITO, WATARU, KAZUKI SHIGA i MIKIO BAKKE. "Comparison of Detection Limits for Allergenic Foods between Total Adenylate (ATP+ADP+AMP) Hygiene Monitoring Test and Several Hygiene Monitoring Approaches". Journal of Food Protection 83, nr 7 (11.03.2020): 1155–62. http://dx.doi.org/10.4315/jfp-20-017.
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ABSTRACT Validation and verification of cleaning and inspection methods are essential to prevent the spread of allergens via cross-contact. Among the hygiene monitoring tests used on-site, the ATP test is rapid and provides quantifiable results. Nevertheless, because a wide variety of foods contain significant amount of ADP and/or AMP due to the degradation of ATP, the ATP+ADP+AMP (A3) test is preferred for detecting food debris. Hence, the A3 test may be valuable in screening food debris that may contain residual allergens. In this study, the detection limits of the A3 test for 40 foods that are regulated in several countries as allergenic were compared with those of the other hygiene monitoring tests used on-site: the conventional ATP test with similar sensitivity for ATP, the protein swab test that detects as little as 50 μg of protein, and the lateral flow immunoassay (LFI). The A3 test demonstrated lower detection limits than did the ATP test. The detection sensitivity of the A3 test was greater than that of the protein swab test except for its use on gelatin (extracted protein). The cleaning validation performance using a stainless steel model in fish and meat revealed that the A3 test is efficient in verifying the levels of remaining food debris. Although LFI displayed the best sensitivities for 10 of 14 foods, it is not commercially available for some specific allergens; however, the A3 test can detect such food debris. Moreover, the detection limits of the A3 test were preferable or comparable to those of LFI for crustacean shellfish and for processed grains, with the exception of wheat flour and buckwheat. A field study in a food processing plant demonstrated that the amount of both A3 and milk protein (enzyme-linked immunosorbent assay) considerably decreased as the cleaning steps progressed. Therefore, the A3 test is effective in detecting the risk for allergen cross-contact after inadequate cleaning. HIGHLIGHTS
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Dodd, Misty D., Stephen D. Ebbs, David J. Gibson i Peter Filip. "Alteration of Root Growth by Lettuce, Wheat, and Soybean in Response to Wear Debris from Automotive Brake Pads". Archives of Environmental Contamination and Toxicology 67, nr 4 (24.06.2014): 557–64. http://dx.doi.org/10.1007/s00244-014-0053-3.
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Beck-Broichsitter, Steffen, Heiner Fleige i Rainer Horn. "Effect of organic residues on soil properties of loamy topsoil of haplic Luvisol in Northern Germany". Die Bodenkultur: Journal of Land Management, Food and Environment 71, nr 1 (22.06.2020): 31–39. http://dx.doi.org/10.2478/boku-2020-0004.
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SummaryThe application of organic residues should ensure a sufficient air capacity (AC) and plant available water capacity (AWC) to improve the soil aeration and water supply for plant roots, whereas the air permeability (ka) primarily depends on the number of functional and, therefore, connected pores. The objective of the study was to investigate the effect of digestates derived from maize (Zea mays L.), sugar beet (Beta vulgaris L.), and wheat (Triticum aestivum L.) in ratios of 100%, 80%, and 20%, respectively; compost of shrub debris; and sewage sludge on AC, AWC, and ka values, including the pore continuity indices (c2, c3) of a loamy Ap horizon of a haplic Luvisol. The results indicate that AC values increase from 0.142 of up to 0.191 cm3 cm−3, but pore continuities and AWC values decrease from 0.143 down to 0.111 cm3 cm−3, except for wheat-containing digestate (20w80b), which shows an opposite trend. The application of organic residues can compensate low AC values but not the AWC values. The wheat-containing digestate should be preferred for improving the water-holding capacity and, therefore, the water supply for plant roots.
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Matelionienė, Neringa, Skaidrė Supronienė, Arman Shamshitov, Evelina Zavtrikovienė, Sigita Janavičienė i Gražina Kadžienė. "Weeds in Cereal Crop Rotations May Host Fusarium Species That Cause Fusarium Head Blight and Grain Weight Losses in Wheat". Agronomy 12, nr 11 (4.11.2022): 2741. http://dx.doi.org/10.3390/agronomy12112741.
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Fusarium Head Blight (FHB) is one of the most common worldwide wheat and other small grain diseases. The infection is caused by Fusarium graminearum and other related species, which significantly reduce grain yield and contaminate grains with mycotoxins which are harmful for humans and animals. Fusarium pathogen survives the winter well in plant debris left on the field. Weeds around and within crops are alternative hosts of Fusarium fungi when an economically important host plant is not present. This article focuses on the determination of DNA content of Fusarium species (F. graminearum and F. avenaceum) in artificially inoculated wheat plants with isolates from weeds, as well as its influence on the severity of FHB and spring wheat 1000-grain weight under field conditions. Fungal DNA content in grains was evaluated by quantitative real-time PCR. The results showed that the DNA concentration of F. graminearum was significantly higher in the grain than F. avenaceum. The severity of FHB when wheat heads were inoculated with F. graminearum was significantly higher than with F. avenaceum. All F. graminearum strains statistically significantly reduced the weight of spring wheat grains, while F. avenaceum did not affect the weight of 1000 grain. This investigation has shown that weeds in crop rotations are a potential source of FHB infection. However, the severity of the disease is more affected by the Fusarium species than the host plant. This experiment is, to our knowledge, the first report on the estimation of Fusarium DNA content in artificially inoculated wheat plants with isolates from weeds, as well as its comparison with pathogenicity to wheat and its effect on 1000-grain weight.
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Peterson, G. L., M. R. Bonde i J. G. Phillips. "Size-Selective Sieving for Detecting Teliospores of Tilletia indica in Wheat Seed Samples". Plant Disease 84, nr 9 (wrzesień 2000): 999–1007. http://dx.doi.org/10.1094/pdis.2000.84.9.999.
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A method was developed to isolate teliospores of Tilletia indica from infested grain. The technique was evaluated to determine its sensitivity for detection and quantification of teliospores, the time required to conduct an individual test, and its utility for the detection and identification of the pathogen for phytosanitary regulation and seed certification. A seed wash of a 50-g grain sample was washed through 53-μm and 20-μm pore size nylon screens to remove unwanted debris and to concentrate and isolate teliospores. The material retained in the 20-μm screen was suspended for direct microscopic examination or plated on water agar for teliospore germination and identification by polymerase chain reaction (PCR) utilizing two pairs of T. indica-specific primers. The reliability of detection for both light microscopy and PCR are 100% at an infestation of five teliospores per 50-g sample. The proportion of teliospores recovered from grain samples artificially infested with T. indica was 0, 82, 88, 81, and 82%, respectively, at infestation levels of 0, 1, 2, 5, and 10 teliospores per 50-g wheat sample. Extraction efficiency was comparable to the centrifuge seed-wash method currently used by most seed health laboratories. Sample analysis using size-selective sieving was more than 83% faster than the standard centrifuge seed wash.
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JENKYN, J. F., R. J. GUTTERIDGE i A. D. TODD. "A comparison of management regimes for one-year rotational set-aside within a sequence of winter wheat crops, and of growing wheat without interruption. 3. Effects on diseases". Journal of Agricultural Science 130, nr 4 (czerwiec 1998): 399–410. http://dx.doi.org/10.1017/s0021859698005450.
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Different management regimes for 1-year rotational set-aside were tested in three experiments that followed winter wheat and started in autumn 1988–90. The regimes included operations that prevented the establishment of volunteers or allowed them to establish and persist until either spring or summer, and also altered the distribution of debris from the winter wheat that preceded the set-aside. For comparison, treatments in the set-aside year also included winter wheat.Samples taken in spring from the first test crop showed that there were few significant or consistent effects on leaf diseases of growing the wheat after different set-aside treatments or after winter wheat. There were significant effects of the set-aside treatments on root and stem base diseases but some of the effects, and the apparent absence of others, are not easily reconciled with current understanding of the biology of the pathogens concerned. In summer, eyespot (Pseudocercosporella herpotrichoides) was most severe after winter wheat and least severe after ryegrass. Severity after the other set-aside treatments did not differ significantly. There was more sharp eyespot (Rhizoctonia cerealis) in plots that had been ploughed at the start of the set-aside year, including those sown with winter wheat, than in those that had not. Brown foot rot (Fusarium spp.) was equally severe where the wheat followed wheat or where it followed set-aside treatments that allowed volunteers to develop, and less so where the development of volunteers was prevented. Take-all (Gaeumannomyces graminis var. tritici) was most severe after winter wheat and more severe after set-aside treatments that allowed volunteers to develop and survive through the winter than after those that did not. Effects of ryegrass (Lolium perenne ssp. multiflorum) on take-all in the following wheat were particularly variable, perhaps because ryegrass is a host of both the take-all fungus and of Phialophora graminicola, one of its principal antagonists.
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Jouve, N., C. L. McIntyre i J. P. Gustafson. "Chromosome preparations from protoplasts: in situ hybridization banding pattern of a dispersed DNA sequence in rye (Secale cereale L.)". Genome 34, nr 4 (1.08.1991): 524–27. http://dx.doi.org/10.1139/g91-080.
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The utilization of genome-specific DNA sequences coupled with in situ hybridization for chromosome karyotyping in wheat, rye, and triticale has been of limited value because of the presence of cellular and cytoplasmic debris. The use of protoplasts, thus eliminating cellular debris, has been shown to improve the level of detection of low-copy and unique DNA sequences in cereals. Therefore, the use of protoplasts could represent an appropriate tool to improve the results of karyotyping cereal chromosomes with genome-specific DNA sequences. This paper describes the results on the comparative application of protoplasts and squash preparations in the analysis of physical mapping of a dispersed DNA sequence (pSc119.1) to rye chromosomes by in situ hybridization. Individual chromosomes of rye were not distinguishable by their hybridization patterns to pSc119.1 when squash preparations were used. These showed an undefined distribution of the DNA probe that covered apparently the entire length of each rye chromosome. However, considerable improvement was observed for the differential distribution of the pSc119.1 DNA sequence in protoplast preparations. The karyotypic banding pattern of pSc119.1 showed a better banding pattern than can be observed using the C-banding technique. Therefore, the use of protoplasts hybridized with dispersed DNA markers could be of more value in monitoring chromosome karyotypes than existing cytological techniques.Key words: biotin labeling, dispersed sequences, rye.
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Schmale, David G., Denis A. Shah i Gary C. Bergstrom. "Spatial Patterns of Viable Spore Deposition of Gibberella zeae in Wheat Fields". Phytopathology® 95, nr 5 (maj 2005): 472–79. http://dx.doi.org/10.1094/phyto-95-0472.
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An increased understanding of the epidemiology of Gibberella zeae will contribute to a rational and informed approach to the management of Fusarium head blight (FHB). An integral phase of the FHB cycle is the deposition of airborne spores, yet there is no information available on the spatial pattern of spore deposition of G. zeae above wheat canopies. We examined spatial patterns of viable spore deposition of G. zeae over rotational (lacking cereal debris) wheat fields in New York in 2002 and 2004. Viable, airborne spores (ascospores and macroconidia) of G. zeae were collected above wheat spikes on petri plates containing a selective medium and the resulting colonies were counted. Spores of G. zeae were collected over a total of 68 field environments (three wheat fields during 54 day and night sample periods over 2 years) from spike emergence to kernel milk stages of local wheat. Spatial patterns of spore deposition were visualized by contour plots of spore counts over entire fields. The spatial pattern of spore deposition was unique for each field environment during each day and night sample period. Spore deposition patterns during individual sample periods were classified by spatial analysis by distance indices (SADIE) statistics and Mantel tests. Both analyses indicated that the majority (93%) of the spore deposition events were random, with the remainder being aggregated. All of the aggregated patterns were observed during the night. Observed patterns of spore deposition were independent of the mean number of viable spores deposited during individual sample periods. The spatial pattern for cumulative spore deposition during anthesis in both years became aggregated over time. Contour maps of daily and cumulative spore deposition could be compared with contour maps of FHB incidence to gain insights into inoculum thresholds and the timing of effective inoculum for infection.
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Milus, E. A., i D. B. Chalkley. "Effect of Previous Crop, Seedborne Inoculum, and Fungicides on Development of Stagonospora Blotch". Plant Disease 81, nr 11 (listopad 1997): 1279–83. http://dx.doi.org/10.1094/pdis.1997.81.11.1279.
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Stagonospora blotch of wheat has been difficult to control in the eastern United States. The objectives of this research were to evaluate the effects of field inoculum, seedborne inoculum, and seed treatment and foliar fungicides on Stagonospora blotch development and to develop more effective management strategies. In 1995 and 1996, similar experiments were established in “infested” and “clean” fields using two seed lots of Coker 9543 (“low” and “high” levels of seed infection) and six seed or foliar fungicide treatments. Planting in clean fields, planting seed with a low level of seedborne inoculum, treating seed with difenoconazole or triadimenol + thiram, and applying propiconazole or tebuconazole to the foliage all contributed toward reducing leaf infections by Stagonospora nodorum, severity of leaf and glume blotch, and incidence of S. nodorum in the harvested seed. Propiconazole alone was the least effective treatment. Planting in an infested field tended to negate the beneficial effects of low level of seed infection and fungicide seed treatments. Crop rotations and tillage that allow wheat debris to decompose before the next wheat crop along with difenoconazole or triadimenol seed treatment to reduce seedborne inoculum should be sufficient to avoid serious losses. In fields where wheat is grown every year, tillage and seed treatment would still be helpful, but a foliar fungicide at GS 8 may be necessary for adequate control. Applying an effective fungicide to seed appears to be a more efficient means of reducing seedborne inoculum than does producing seed with low levels of inoculum.
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Paul, P. A., S. M. El-Allaf, P. E. Lipps i L. V. Madden. "Rain Splash Dispersal of Gibberella zeae Within Wheat Canopies in Ohio". Phytopathology® 94, nr 12 (grudzień 2004): 1342–49. http://dx.doi.org/10.1094/phyto.2004.94.12.1342.
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Rain splash dispersal of Gibberella zeae, causal agent of Fusarium head blight of wheat, was investigated in field studies in Ohio between 2001 and 2003. Samplers placed at 0, 30, and 100 cm above the soil surface were used to collect rain splash in wheat fields with maize residue on the surface and fields with G. zeae-infested maize kernels. Rain splash was collected during separate rain episodes throughout the wheat-growing seasons. Aliquots of splashed rain were transferred to petri dishes containing Komada's selective medium, and G. zeae was identified based on colony and spore morphology. Dispersed spores were measured in CFU/ml. Intensity of splashed rain was highest at 100 cm and ranged from 0.2 to 10.2 mm h-1, depending on incident rain intensity and sampler height. Spores were recovered from splash samples at all heights in both locations for all sampled rain events. Both macroconidia and ascospores were found based on microscopic examination of random samples of splashed rain. Spore density and spore flux density per rain episode ranged from 0.4 to 40.9 CFU cm-2 and 0.4 to 84.8 CFU cm-2 h-1, respectively. Spore flux density was higher in fields with G. zeae-infested maize kernels than in fields with maize debris, and generally was higher at 0 and 30 cm than at 100 cm at both locations. However, on average, spore flux density was only 30% lower at 100 cm (height of wheat spikes) than at the other heights. The log of spore flux density was linearly related to the log of splashed rain intensity and the log of incident rain intensity. The regression slopes were not significantly affected by year, location, height, and their interactions, but the intercepts were significantly affected by both sampler height and location. Thus, our results show that spores of G. zeae were consistently splash dispersed to spike heights within wheat canopies, and splashed rain intensity and spore flux density could be predicted based on incident rain intensity in order to estimate inoculum dispersal within the wheat canopy.
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Young, S. Y., i D. C. Steinkraus. "Control of Armyworm on Heading Wheat with Bacillus Thuringiensis Products and Baculoviruses, 1994". Arthropod Management Tests 21, nr 1 (1.01.1996): 318–19. http://dx.doi.org/10.1093/amt/21.1.318a.
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Abstract All applications were made on 26 Apr to ‘Wakefield’ winter wheat drilled on 6 inch row spacings on heading wheat in Lonoke Co., AR. A bicycle-type CO2 sprayer with a 12 ft boom equipped with TX-4 hollowcone nozzles on a 20-inch spacing, calibrated to deliver 10.5 gal/acre at 40 psi, was used for all treatments. Plots were 12 X 50 ft separated by 6 ft borders, arranged in a RCB design with 4 replications. A spreader sticker (CS-7) was added at a concentration of 1 ml/gal. The application was made late in the afternoon in a moderate breeze. No rainfall occurred during the test. Six Bacillus thuringiensis products and 3 viruses [Anagrapha falcifera NPV (AfNPV), Pseudaletia unipuncta NPV (AWNPV) and P. unipuncta GV (AWGV) were tested. Larval precounts made from the perimeter of the plots prior to the application showed a mean of 14.9 larvae per ft2. Post application larval counts were made at 4 and 7 DAT. Two samples per plot, each 3 ft in length and 12 inches in width, were taken by searching the soil surface, debris, and base of plants for larvae. Just prior to the search, the plants were jostled so that larvae on plants would fall to the ground. Yields were not taken. Larvae were collected from control and virus plots at 4 and 7 DAT. Larvae (25 per replicate) were individually placed in 1 oz plastic cups half-filled with pinto bean diet and held until death or adult emergence. Data from counts and collections were analyzed by ANOVA.
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Suffert, Frédéric, Virginie Ravigné i Ivan Sache. "Seasonal Changes Drive Short-Term Selection for Fitness Traits in the Wheat Pathogen Zymoseptoria tritici". Applied and Environmental Microbiology 81, nr 18 (6.07.2015): 6367–79. http://dx.doi.org/10.1128/aem.00529-15.
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ABSTRACTIn a cross-infection experiment, we investigated how seasonal changes can affect adaptation patterns in aZymoseptoria triticipopulation. The fitness of isolates sampled on wheat leaves at the beginning and at the end of a field epidemic was assessed under environmental conditions (temperature and host stage) to which the local pathogen population was successively exposed. Isolates of the final population were more aggressive, and showed greater sporulation intensity under winter conditions and a shorter latency period (earlier sporulation) under spring conditions, than isolates of the initial population. These differences, complemented by lower between-genotype variability in the final population, exhibited an adaptation pattern with three striking features: (i) the pathogen responded synchronously to temperature and host stage conditions; (ii) the adaptation concerned two key fitness traits; (iii) adaptation to one trait (greater sporulation intensity) was expressed under winter conditions while, subsequently, adaptation to the other trait (shorter latency period) was expressed under spring conditions. This can be interpreted as the result of short-term selection, driven by abiotic and biotic factors. This case study cannot yet be generalized but suggests that seasonality may play an important role in shaping the variability of fitness traits. These results further raise the question of possible counterselection during the interepidemic period. While we did not find any trade-off between clonal multiplication on leaves during the epidemic period and clonal spore production on debris, we suggest that final populations could be counterselected by an Allee effect, mitigating the potential impact of seasonal selection on long-term dynamics.
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Crook, A. D., T. L. Friesen, Z. H. Liu, P. S. Ojiambo i C. Cowger. "Novel Necrotrophic Effectors from Stagonospora nodorum and Corresponding Host Sensitivities in Winter Wheat Germplasm in the Southeastern United States". Phytopathology® 102, nr 5 (maj 2012): 498–505. http://dx.doi.org/10.1094/phyto-08-11-0238.
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Stagonospora nodorum blotch (SNB), caused by the necrotrophic fungus Stagonospora nodorum (teleomorph: Phaeosphaeria nodorum), is among the most common diseases of winter wheat in the United States. New opportunities in resistance breeding have arisen from the recent discovery of several necrotrophic effectors (NEs, also known as host-selective toxins) produced by S. nodorum, along with their corresponding host sensitivity (Snn) genes. Thirty-nine isolates of S. nodorum collected from wheat debris or grain from seven states in the southeastern United States were used to investigate the production of NEs in the region. Twenty-nine cultivars with varying levels of resistance to SNB, representing 10 eastern-U.S. breeding programs, were infiltrated with culture filtrates from the S. nodorum isolates in a randomized complete block design. Three single-NE Pichia pastoris controls, two S. nodorum isolate controls, and six Snn-differential wheat controls were also used. Cultivar–isolate interactions were visually evaluated for sensitivity at 7 days after infiltration. Production of NEs was detected in isolates originating in each sampled state except Maryland. Of the 39 isolates, 17 produced NEs different from those previously characterized in the upper Great Plains region. These novel NEs likely correspond to unidentified Snn genes in Southeastern wheat cultivars, because NEs are thought to arise under selection pressure from genes for resistance to biotrophic pathogens of wheat cultivars that differ by geographic region. Only 3, 0, and 23% of the 39 isolates produced SnToxA, SnTox1, and SnTox3, respectively, by the culture-filtrate test. A Southern dot-blot test showed that 15, 74, and 39% of the isolates carried the genes for those NEs, respectively; those percentages were lower than those found previously in larger international samples. Only two cultivars appeared to contain known Snn genes, although half of the cultivars displayed sensitivity to culture filtrates containing unknown NEs. Effector sensitivity was more frequent in SNB-susceptible cultivars than in moderately resistant (MR) cultivars (P = 0.008), although some susceptible cultivars did not exhibit sensitivity to NEs produced by isolates in this study and some MR cultivars were sensitive to NEs of multiple isolates. Our results suggest that NE sensitivities influence but may not be the only determinant of cultivar resistance to S. nodorum. Specific knowledge of NE and Snn gene frequencies in this region can be used by wheat breeding programs to improve SNB resistance.
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Vlasova, O. I., G. R. Dorojko, V. M. Perederieva i O. G. Chabaldas. "Efficient activity of soil depending on of precursors and major treatment of soil when cultivating winter wheat". E3S Web of Conferences 285 (2021): 06008. http://dx.doi.org/10.1051/e3sconf/202128506008.
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The article presents data on the change in the enzymatic activity of the soil in winter wheat crops under the influence of the methods and techniques of tillage and the previous crop in the Central Ciscaucasus zone. The studies were carried out in the zone of the Central Ciscaucasia on the basis of the experimental station of Stavropol State Agrarian University. The determination of the activity of invertase shows that its maximum values are in the variants of the combined treatment, which is associated with more favorable hydrothermal conditions of the arable layer of the soil. Thus, according to its predecessor, pea + oats for green fodder, invertase activity is 27.9 mg of glucose per 1 g of soil for 40 hours, which is almost twice as high in comparison with surface treatment and three times with plowing. The decrease in the activity of invertase during dump processing indicates a rapid rate of mineralization of organic matter. Catalase activity on the studied precursors: on peas with oats for green fodder 1.6 and 1.3; 1.5 and 1.8 peas; for corn silage 1.5 and 1.4 ml 0.1 n. KMnO4 per 1 g of soil for 20 minutes. Revealed a decrease in activity under the influence of plowing, as urease enters the soil with plant debris. When dumping treatment due to movement of plant residues in the underlying layers, the activity of this enzyme decreases to 0.8–0.9 mg of N-NH4 per 10 g of soil for 4 hours, whereas with surface treatment, depending on its predecessor, it is 0.8–– 1.3 mg of N-NH4 / 10 g of soil for 4 hours, with a combination of 1.0–1.1, and for shallow soil, 1.1–1.2 mg of N-NH4 / 10 g of soil in 4 hours.
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Van Milgen, Jaap, Larry L. Berger i Michael R. Murphy. "An integrated, dynamic model of feed hydration anddigestion, and subsequent bacterial mass accumulation in the rumen". British Journal of Nutrition 70, nr 2 (wrzesień 1993): 471–83. http://dx.doi.org/10.1079/bjn19930141.
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Hydration of feeds and bacterial attachment to feed particles are thought to play major roles in rumen digestion of fibrous feedstuffs. The objective of the present study was to integrate these phenomena in a mechanistic model that could be used for data analysis. The proposed model was based on the conversion of biomass, where digestion end-products can be used for the synthesis of bacterial mass. Digestion of the potentially digestible fraction and subsequent accumulation of bacterial mass was based on a sequential, three-compartment model. These compartments represented substrate undergoing hydration, digestion, and bacterial mass accumulation. A fraction of the substrate was used for synthesis of bacterial mass. It was assumed that these bacteria associate either temporarily or permanently with the remaining substrate. Dacron bags containing either dry or fully-hydrated lucerne (Medicago sativa), maize (Zea mays) cobs, orchard grass (Dactylis glomeratd), and wheat straw were incubated in the rumen of a steer that was infused continuously with (15NH4)2SO4. The15N-enrichments of isolated particle-associated bacteria and residue remaining in the bags were used to estimate bacterial attachment. Substrate remaining and microbial mass accumulation were analysed simultaneously. Hydration did not appear to limit digestion. Fractional rate of digestion and appearance of attached bacterial mass was fastest for lucerne. For lucerne, 5 % of the digestion end-products were used for synthesis of bacteria that associated with the substrate, whereas for maize cobs, orchard grass, and wheat straw this was 16, 14, and 19% respectively. Less than 2% of digestion end-products were used for synthesis of bacteria that permanently remained associated with the substrate. Permanent association can occur only with the indigestible fraction, and probably represents bacterial debris. Lysis and/or detachment of bacterial cells was highest for lucerne, and was indicative of the rapid dynamics of lucerne digestion.
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Oades, JM, AG Waters, AM Vassallo, MA Wilson i GP Jones. "Influence of management on the composition of organic matter in a red-brown earth as shown by 13C nuclear magnetic resonance". Soil Research 26, nr 2 (1988): 289. http://dx.doi.org/10.1071/sr9880289.
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Samples were obtained from the same red-brown earth: (a) in an undisturbed state, (b) after 60 years of an exploitive wheat-fallow rotation and (c) after 40 years under a fertilized mixed grass-legume pasture. Organic materials were concentrated in various fractions which enabled comparative chemical composition of the organic materials in the three soils by 13C CPMAS n.m.r. spectroscopy. Despite more than twofold differences in the organic carbon content of the soils, the chemistry of the organic matter in the soils was similar, particularly organic matter associated with clay fractions. Most of the differences detected were associated with plant debris in particles > 20 �m which contained most of the aromatic carbon. The results indicate a rapid disappearance of phenolic-carbon which originates in lignins. The composition of sodium hydroxide extracts reflects quite well the composition of the organic matter in the soil. It is concluded that in a particular soil type, changes in amounts and nature of added photosynthate do not change the composition of the organic matter which is controlled by the microbial biomass and interactions of the biomass and its decomposition products with the soil matrix. Implications of this conclusion for the turnover of organic carbon in soil and stability of soil structure are discussed.
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Moss, AJ, i CL Watson. "Rain impact soil crust. III. Effects of continuous and flawed crusts on infiltration, and the ability of plant covers to maintain crustal flaws". Soil Research 29, nr 2 (1991): 311. http://dx.doi.org/10.1071/sr9910311.
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Experiments on unsteady infiltration, through rain-impact soil crusts on an albaqualf, employed 70 mm diameter cylinders surrounded by airsplash-exchange areas. Significant throttling effects resulted. Circular, fabricated flaws of varying diameter caused strong bypassing of the crust by infiltrating water. As the percentage of total area flawed rose from 1% to 10%, infiltration rates rose from near those of fully-crusted values to those of uncrusted values, further areal increases bringing little change. This result suggested three-dimensional water movement beneath flaws. Sheltering by plant covers produced flaws in the rain-impact soil crust. However, sheltered areas often acted as traps for incoming, finely comminuted, airsplash debris which, once deposited, could also throttle infiltration. Moreover, the compacted layer, the main throttling agent of the rain-impact soil crust, often extended laterally into sheltered areas. Wheat-straw stems, less than a drop diameter apart, were effective flaw preservers, even under heavy airsplash, inhibiting formation of the compacted layer and stimulating removal of airsplash deposits. Grass covers, dense enough to intercept all raindrops, were also highly effective against infiltration throttling because intercepted raindrops were converted, via the double-edge effect, into non-erosive, fine, impact droplets which could not disturb the soil.
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Prew, R. D., J. E. Ashby, E. T. G. Bacon, D. G. Christian, R. J. Gutteridge, J. F. Jenkyn, W. Powell i A. D. Todd. "Effects of Incorporating or Burning Straw, and of Different Cultivation Systems, on Winter Wheat Grown on Two Soil Types, 1985–91". Journal of Agricultural Science 124, nr 2 (kwiecień 1995): 173–94. http://dx.doi.org/10.1017/s0021859600072853.
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SUMMARYDisposal methods for straw from continuous winter wheat were tested on two soil types, a flinty silty clay loam and a sandy loam, over 7 years (1985–91). The methods tested were burnt or chopped straw in full factorial combination with four cultivation methods (tined to 10 cm, tined to 10 cm then to 20 cm; ploughed to 20 cm; tined to 10 cm then ploughed to 20 cm). Measurements were taken to determine the effects on crop establishment and growth, pest and disease incidence, and the consequent effects on yield. Another experiment (1985–91) on the flinty silty clay loam site, investigated the interactions between straw treatments (burnt, baled or chopped in plots that were all shallow cultivated to 10 cm) and five other factors; namely, time of cultivation, insecticides, molluscicides, fungicides and autumn nitrogen. All the straw x cultivation systems allowed satisfactory crops to be established but repeated incorporation of straw using shallow, non-inversion cultivations resulted in very severe grass-weed problems. Early crop growth, as measured by above-ground dry matter production, was frequently decreased by straw residues, but the effect rarely persisted beyond anthesis. Pests were not a problem and their numbers were not greatly affected either by straw or cultivation treatments, apart from yellow cereal fly which, especially on the heavier soil, was decreased by treatments which left much straw debris on the soil surface. Incorporating straw also caused no serious increases in the incidence of diseases. Indeed, averaged over all sites and years, eyespot and sharp eyespot were both slightly but significantly less severe where straw was incorporated than where it was burnt. Eyespot, and even more consistently sharp eyespot, were often more severe after ploughing than after shallow, non-inversion cultivations. Effects on take-all were complex but straw residues had much smaller effects than cultivations. Initially the disease increased most rapidly in the shallow cultivated plots but these also tended to go into the decline phase more quickly so that in the fourth year (fifth cereal crop) take-all was greater in the ploughed than in the shallow cultivated plots. On average, yields did not differ greatly with straw or cultivation systems, although there were clear effects of take-all in those years when the disease was most severe. In the last 2 years, yields were limited by the presence of grass weeds in the plots testing chopped straw incorporated by tining to 10 cm.
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Miljkovic, Ana, i Peter Mantle. "Renal Apoptosis in the Mycotoxicology of Penicillium polonicum and Ochratoxin A in Rats". Life 12, nr 3 (28.02.2022): 352. http://dx.doi.org/10.3390/life12030352.
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Penicillium polonicum K. M. Zaleski, which is common on foodstuffs in Balkan regions that are notable for their history of endemic nephropathy, has been shown experimentally to cause a striking histopathological renal change in rats that are given feed contaminated by this fungus. The nephrotoxic agent(s) are only partially characterized. The principal change seen in the cortico-medullary region is karyocytomegaly, but apoptosis, identified with the ApopTag® methodology, is the first response to a dietary extract of P. polonicum-molded wheat after a few days of exposure. Chromatin debris migrates along the nephrons into the medulla, but whether the damaged epithelial fate is via autophagy is unclear. In intermittent exposure experiments, renal apoptosis was resolved with the cessation of exposure and was restored with renewed exposure. Apoptosis became less evident after 3 months of chronic exposure. In contrast, a relatively high dose of dietary ochratoxin A, a potent nephrocarcinogen in male rats after many months of dietary exposure, gave no evidence of apoptosis in asymptomatic weanlings over a few days of dietary exposure. This was attributed to a masking effect by concomitant marked histological disruption in renal tissue. However, in young adults, renal apoptosis was a primary outcome of dietary exposure to either the P. polonicum extract or to ochratoxin A, but the histopathological response to the former was less distorted. The apparent conflicted use in the literature of P. polonicum as a descriptor is highlighted.
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Grigor, Talinn, i Romina Katchi.db. "Debris of What-Would-Have-Been". Journal of Urban History 41, nr 2 (8.01.2015): 294–306. http://dx.doi.org/10.1177/0096144214563501.
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Mergili, Martin, Michel Jaboyedoff, José Pullarello i Shiva P. Pudasaini. "Back calculation of the 2017 Piz Cengalo–Bondo landslide cascade with r.avaflow: what we can do and what we can learn". Natural Hazards and Earth System Sciences 20, nr 2 (21.02.2020): 505–20. http://dx.doi.org/10.5194/nhess-20-505-2020.
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Abstract. In the morning of 23 August 2017, around 3×106 m3 of granitoid rock broke off from the eastern face of Piz Cengalo, southeastern Switzerland. The initial rockslide–rockfall entrained 6×105m3 of a glacier and continued as a rock (or rock–ice) avalanche before evolving into a channelized debris flow that reached the village of Bondo at a distance of 6.5 km after a couple of minutes. Subsequent debris flow surges followed in the next hours and days. The event resulted in eight fatalities along its path and severely damaged Bondo. The most likely candidates for the water causing the transformation of the rock avalanche into a long-runout debris flow are the entrained glacier ice and water originating from the debris beneath the rock avalanche. In the present work we try to reconstruct conceptually and numerically the cascade from the initial rockslide–rockfall to the first debris flow surge and thereby consider two scenarios in terms of qualitative conceptual process models: (i) entrainment of most of the glacier ice by the frontal part of the initial rockslide–rockfall and/or injection of water from the basal sediments due to sudden rise in pore pressure, leading to a frontal debris flow, with the rear part largely remaining dry and depositing mid-valley, and (ii) most of the entrained glacier ice remaining beneath or behind the frontal rock avalanche and developing into an avalanching flow of ice and water, part of which overtops and partially entrains the rock avalanche deposit, resulting in a debris flow. Both scenarios can – with some limitations – be numerically reproduced with an enhanced version of the two-phase mass flow model (Pudasaini, 2012) implemented with the simulation software r.avaflow, based on plausible assumptions of the model parameters. However, these simulation results do not allow us to conclude on which of the two scenarios is the more likely one. Future work will be directed towards the application of a three-phase flow model (rock, ice, and fluid) including phase transitions in order to better represent the melting of glacier ice and a more appropriate consideration of deposition of debris flow material along the channel.
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Fortner, Rosanne W., i Dan Jax. "What Is the Impact of Beach Debris?" Science Activities: Classroom Projects and Curriculum Ideas 40, nr 1 (styczeń 2003): 27–31. http://dx.doi.org/10.1080/00368120309601110.
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Shoemaker, E. M. "Debris-Influenced Sliding Laws and Basal Debris Balance". Journal of Glaciology 32, nr 111 (1986): 224–31. http://dx.doi.org/10.1017/s0022143000015549.
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AbstractIn order to determine the effect of basal debris drag as a component in a sliding law, it is necessary to know the basal debris concentration. Does, for example, this debris concentration exhibit uniformity, in an average sense, across a valley? What effect does a localized region of high quarryability have on basal debris concentration down-stream? The analysis presented here suggests that, for the case of sparse debris, debris concentration tends to be uniform over the entire bed. Consequently, the debris-drag term in a sliding law will also tend to be uniform.In order to reach the above conclusions, it is necessary to consider debris balance, the balance of the quarrying, abrasion, and debris-flushing rates. This entails proposing and testing quarrying and flushing laws, since these laws have not been previously proposed. It is concluded that the quarrying, flushing, and erosion rates depend weakly on the sliding velocity. Furthermore, the abrasion rate is negligible compared to the quarrying rate. (This conclusion depends partially on the definition of abrasion.) The quarrying rate also depends on other factors such as the effective pressure_pressure-fluctuation mechanism; the cross-valley dependency of this mechanism is investigated. The flushing rate is found to depend on the ratio, N-channel area/bed area, and on average N-channel diameter.
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Shoemaker, E. M. "Debris-Influenced Sliding Laws and Basal Debris Balance". Journal of Glaciology 32, nr 111 (1986): 224–31. http://dx.doi.org/10.3189/s0022143000015549.
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AbstractIn order to determine the effect of basal debris drag as a component in a sliding law, it is necessary to know the basal debris concentration. Does, for example, this debris concentration exhibit uniformity, in an average sense, across a valley? What effect does a localized region of high quarryability have on basal debris concentration down-stream? The analysis presented here suggests that, for the case of sparse debris, debris concentration tends to be uniform over the entire bed. Consequently, the debris-drag term in a sliding law will also tend to be uniform.In order to reach the above conclusions, it is necessary to consider debris balance, the balance of the quarrying, abrasion, and debris-flushing rates. This entails proposing and testing quarrying and flushing laws, since these laws have not been previously proposed. It is concluded that the quarrying, flushing, and erosion rates depend weakly on the sliding velocity. Furthermore, the abrasion rate is negligible compared to the quarrying rate. (This conclusion depends partially on the definition of abrasion.) The quarrying rate also depends on other factors such as the effective pressure_pressure-fluctuation mechanism; the cross-valley dependency of this mechanism is investigated. The flushing rate is found to depend on the ratio, N-channel area/bed area, and on average N-channel diameter.
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Yao, Xin, i Lingjing Li. "Spatial-Temporal Assessment of Debris Flow Risk in the Ms8.0 Wenchuan Earthquake-Disturbed Area". Journal of Disaster Research 11, nr 4 (1.08.2016): 720–31. http://dx.doi.org/10.20965/jdr.2016.p0720.
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For 5 years (2009–2013) after the 2008 Ms8.0 Wenchuan earthquake, rainfall led to the transformation of unconsolidated co-seismic deposits into extensive and severe debris flows, causing significant loss of life and property. For debris flows in the earthquake-disturbed area, a few common concerns exist. What is their spatial-temporal distribution? What are the controlling factors? How much is the rainfall threshold for debris flows? What areas are more susceptible? Where suffered the most severe losses of life and property? Using debris flow characteristics, this study analyzes the relationships between seismic geological factors, geomorphologic factors, extreme rainfall, and debris flows in the 5 years following the earthquake, and draws the following conclusions. (1) There are regional differences in the rainfall threshold for generation of debris flows, and the annual maximum 72-hour accumulated rainfall for triggering a debris flow decreases from pre-seismic periods (135–325 mm) to post-seismic periods (75–160 mm) by 44.4–50.8% in study area. (2) Areas with high debris flow susceptibility and hazard are primarily controlled by seismic geological conditions. (3) The long-term risk of debris flows will fall to moderate, and the affected area will shrink to that around the seismogenic fault. The results of this study will help with meteorological early warning systems, deployment of disaster prevention and control projects, and reconstruction site selection in the post-seismic Longmen Mountain area.
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Sende, J. A., i T. Löhne. "Twisted debris: how differential secular perturbations shape debris disks". Astronomy & Astrophysics 631 (listopad 2019): A141. http://dx.doi.org/10.1051/0004-6361/201935199.
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Context. Resolved images suggest that asymmetric structures are a common feature of cold debris disks. While planets close to these disks are rarely detected, their hidden presence and gravitational perturbations provide plausible explanations for some of these features. Aims. To put constraints on the properties of yet undetected planetary companions, we aim to predict what features such a planet imprints in debris disks undergoing continuous collisional evolution. Methods. We discuss the basic equations, analytic approximations and timescales governing collisions, radiation pressure and secular perturbations. In addition, we combine our numerical model of the collisional evolution of the size and spatial distributions in debris disks with the gravitational perturbation by a single planet. Results. We find that the distributions of orbital elements in the disks are strongly dependent on grain sizes. Secular precession is differential with respect to involved semi-major axes and grain sizes. This leads to observable differences between the big grains tracing the parent belt and the small grains in the trailing halo. Observations at different wavelengths can be used to constrain the properties of a possible planet.
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Klotz, Stephen A., Richard E. Normand i Robert G. Kalinsky. "“Through a Drinking Glass and What Was Found There”: Pseudocontamination of a Hospital's Drinking Water". Infection Control & Hospital Epidemiology 13, nr 8 (sierpień 1992): 477–81. http://dx.doi.org/10.1086/646576.
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AbstractOejective:Examination of suspended macroscopic debris that was noted in hospital cafeteria drinking water over a prolonged period of time.Setting:A tertiary care hospital.Design:A retrospective description of events.Methods:Conventional medical microbiology techniques were employed to determine if contamination of drinking water had occurred.Results:Microscopic examinations of the debris showed live nematodes similar to Strongyloides stercoralis rhabditiform larvae and amoebic trophozoites. A culture of an ice container in the cafeteria yielded coliform bacteria. Hospital employees lost work because of a diarrheal illness thought to be contracted from drinking cafeteria water. Further investigation revealed that the debris contained numerous ciliated organisms, nematodes, fresh water amoebae, bacterial mats, flagellated fungi, and unidentified cysts suggesting that the debris was of a freshwater origin rather than fecal contamination. Another hospital served by a collateral city water line experienced a similar problem. The debris was observed in November when lake water in the reservoir undergoes inversion.Conclusions:Nonpathogenic freshwater microbiota probably originating from the city reservoir were the cause of pseudocontamination of hospital drinking water.
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Lucas, John, i Jon West. "BCPC Diseases Review 2022 – Changing Challenges and Changing Tools for Integrated Crop Management". Outlooks on Pest Management 33, nr 5 (1.10.2022): 201–4. http://dx.doi.org/10.1564/v33_oct_08.
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John Lucas, Editorial Board Member and Jon West, Rothamsted Research suggested that the threat posed by Fusarium is likely to increase due to a number of factors including maize crops extending further northwards. The second presentation, given by Derek Croucher, focused on the impact of mycotoxins on producers. The main processor focus on mycotoxins both in the field and during storage is compliance with current legislation, including the ability to test effectively and analyse samples, as well as mitigation measures. There are parallels with legislation of plant protection products, and concerns about potential changes due to exit from the EU. To date these have not occurred, but there is the possibility of GB adoption of EU rules by retailers to facilitate trade. The Food Standards Agency have a priority list of contaminants with maximum limits for mycotoxins in particular foodstuffs, exemplified by current permitted levels for T-2/HT-2 toxins in unprocessed and milled oats. The primary problem in UK oats is Fusarium langsethiae, which causes a mainly symptomless disease, varying in incidence from year to year, with some "high" years, especially in Scotland. There are no commercially viable field mitigation measures. Milling reduces contamination, but this varies and is not batch to batch predictable. There is no reliable rapid test for toxin contamination in oats, and testing by LC-MS/MS is expensive and takes time. In severe years, around 10 – 30% of unprocessed oats would be non-compliant, and as much as 20% of processed products. Identification of compliant versus non-compliant products is challenging and poses a significant risk of recall and reputational damage. The 2022 Diseases review was held at the NIAB Park Farm, Cambridge on October 19th 2022 with a mix of in person and online delegates. The meeting was chaired by Jenna Watts, Head of Plant Health and IPM at the Agriculture and Horticulture Development Board (AHDB). She outlined the current issues and challenges for crop production including climate change, the evolution of pathogen populations to overcome host resistance and pesticides, alterations in the regulatory framework, and changing consumer priorities. New tools are available for disease diagnosis and control, but how can they be most effectively used for integrated crop management? The first two presentations dealt with the issue of mycotoxin contamination of small grain cereals. Professor Simon Edwards (Harper Adams University College) described the various mycotoxins in cereal crops infected by different Fusarium species causing the head blight complex. On wheat the main problems are deoxynivalenol (DON) and zearalenone (ZON) produced by F. graminearum and F. culmorum, while HT-2 and T-2 toxins produced by F. langsethiae and F. sporothrichioides are more of an issue in oats. Mycotoxin profiles vary by cereal, region and season, and exceed permitted regulatory limits in some crops and years. Risk factors for head blight are well known and include crop debris (the main source of inoculum), a warm spring, and heavy rainfall with high humidity in summer. In experimental trials, agronomy accounts for relatively little of the variation in mycotoxin levels. Maize as the previous crop is a major risk factor, along with min tillage and direct drilling. Ploughing or chopping and mixing of debris reduce mycotoxin levels in the crop. There is limited current varietal variation in resistance to head blight. Some fungicides including prothioconazole, metconazole and tebuconazole applied at T3 can reduce DON levels, while Adepidyn (pydiflumetofen) a new but not yet registered SDHI shows some promise for head blight control and toxin reduction. Integrated management to minimize Fusarium mycotoxins in milling wheat therefore combines the use of less susceptible varieties, avoiding high risk crops such as maize in rotations, intense cultivation if a high-risk previous crop has been grown, application of an effective fungicide (or mixture) at T2 and especially T3, and ensuring a timely harvest as late harvesting is associated with higher mycotoxin levels. It was noted that these recommendations are not easy to reconcile with some crop management trends such as reducing cultivations. Professor Edwards also presented some data on HT-2 and T-2 occurrence in oats, and tactics for reducing risk such as switching to spring varieties, or taller more Fusarium resistant varieties, long rotations, and the use of cultivations. Climate change models suggest that the threat posed by Fusarium is likely to increase due to a number of factors including maize crops extending further northwards,