Communications in agricultural and applied biological sciences最新文献

Grass seed crops (ryegrass), a minor crop in Belgium, should be managed more intensively and in an arable way, comparable with the intensive wheat culture. Even more important than higher seed yields are stable, higher yields over time, Integrated pest management (IPM) forms the framework around this intensification. Two similar seed production field trials--one with perennial ryegrass (Lolium perenne L.) and one with Italian ryegrass (Lolium multiflorum L.)--were conducted in 2014, dealing with 4 SDHI fungicides (bixafen, boscalid, fluxapyroxad and isopyrazam) that were compared with an untreated control and some reference treatments. There were four application times (stages): i.e. early stem elongation--BBCH 33 (T1), ear tips visible--BBCH 51 (T2), full ear, begin of flowering--BBCH 61 (T3) and end of flowering--BBCH 69 (T4). Except for the Italian ryegrass trial, only the last three stages were used. In the Italian ryegrass trial, which had only sporadic incidence of disease, all T3 treatments clearly increased seed yield compared with the untreated control, by 13% on average. For the T2 treatments only Fandango and Adexar clearly out yielded the control. The curative T4 treatment (Tilt + Corbel) tended to increase seed yield, but this was not significant. Seed yield differences could not be explained by variations in thousand seed weight (TSW), leaf withering and NDVI scores (crop reflectance). The disease pressure (crown rust) was very low before flowering, but stem rust developed strongly during the last 2 weeks before harvest of the perennial ryegrass trial. Yield responses were mostly pronounced at the T3 treatment. Except for Fandango and Horizon, all T3 treatments clearly increased yield in comparison with the untreated control, by 18.4% on average. The T4 treatment (Tilt + Corbel) could not repair the crop damage. Further seed yield data are discussed in relation to yield components, TSW, leaf withering and vegetation index (NDVI). An integrated approach for a single, profitable fungicide application in grass seed will be necessary, taking into account the disease development during the season and depending upon grass species and variety.

Integrated pest management has been implemented as a general practice by EU legislation. As weed control actually is the most important crop protection measure in maize for Western Europe, the new legislation will have its impact. The question is of course which systems can be successfully implemented in practice with respect to labour efficiency and economical parameters. During 3 successive growing seasons (2007, 2008, 2009) weed control in maize was evaluated, the main focus was put on different techniques of integrated weed control and was compared with chemical weed control. Additionally, during 4 successive growing seasons (2011, 2012, 2013 and 2014) two objects based on integrated weed control and two objects based on mechanical weed control were compared to about twenty different objects of conventional chemical weed control. One of the objects based on mechanical weed control consisted of treatment with the flex-tine harrow before and after emergence in combination with chemical weed control at a reduced rate in 3-4 leave stage. The second one consisted of broadcast mechanical treatments before and after emergence followed by a final in-row application of herbicides and an inter-row cultivation at 6-7(8) leave stage. All trials were conducted on the Experimental farm of Bottelare HoGent-UGent on a sandy loam soil. Maize was growing in 1/3 crop rotation. The effect on weed growth as well as the economic impact of the different applications was evaluated. Combining chemical and mechanical weed control is a possible option in conventional farming but the disadvantages must be taken into account. A better planned weed control based on the real present weed-population in combination with a carefully thought-out choice of herbicides should also be considered as an IPM--approach.

Observations on population density of plant parasitic nematodes occurring in rhizosphere of broad bean cultivated in the crop rotation and long-term monoculture were performed during 2013-2014. 13 species were observed: Trichodorus primitivus, T. viruliferus, Paratrichodorus pachydermus, Criconema annuliferum, Paratylenchus projectus, Bitylenchus dubius, Merlinius brevidens, Pratylenchus fallax, P. flakkensis, P. neglectus, Heterodera triffolii, H. goettingiana, and Ditylenchus dipsaci. In monoculture plots 70-80% of eggs inside Heterodera cysts were colonized by pathogenic fungi (v.s. 50-62% of cysts from crop rotation). 12-18% of specimens of Pratylenchus species were colonized by the nematode-pathogenic bacteria: Bacillus penetrans.

Soil monitoring was accomplished at 76 former pesticide storehouses in Kazakhstan. Gas chromatography analysis was limited to the organochlorine pesticides DDT (p,p'-dichloro-diphenyl-trichloroethane) and HCH (hexachlorocyclohexane), and their associated metabolites and isomers: 2.4'-DDD (p,p'-dichlorodiphenyl dichloroethane); 4.4'-DDD; 4.4'-DDT; 4.4'-DDE (p,p'-dichlorodiphenyl-dichloroethylene); α-HCH; β-HCH and γ-HCH. The studies showed exceeding of Maximum Acceptable Concentration (MAC) by 10 times at soil samples taken at 24 former pesticide storehouses, and the basic pollutants were isomers of α-HCH, β-HCH and metabolite of 4.4'-DDE, 4.4'-DDT, supplemented by heavy metals. Monitoring data demonstrated the potential ecological danger and health risk posed by the sites, especially those located near populated areas. In order to eliminate the negative environmental and health effect it was proposed to use phytotechnology with second generation biofuel crop Miscanthus x giganteus. The technology applied directly at the contaminated area (in situ), helping to decrease costs and to reduce exposure from polluted sites. The plant shows good growing at the soil contaminated by pesticides during vegetation season.

Ergography is a novel technique invented in 2003 by the first author in his attempts to understand, analyze, and quantify at one glance the work of creative scientists without reading through lengthy, usually boring laudations of invited speakers. Traditional enumeration of accomplishments is helpful but less than satisfactory. Simple descriptive texts often do not satisfactorily answer the question of how, when and why certain observations and theories were established and how they influenced the development and advance of scientific fields at large. Five influential entomologists, R.L. Metcalf, H. Schmutterer, P. Karlson, T. Eisner and E.O. Wilson, as well as two biochemists, A. Butenandt and F. Lynen, a few of them still alive, were selected as targets to gain some experience with the new technique superficially resembling chromatograms or spectra. Pretty soon, it became clear that the "when" is easy to answer and follows from simple time diagrams. More difficult is the analysis of the "how" and "why" and "under whose influence" certain subject areas were pursued. Even more difficult to analyze is the impact, if any, certain papers had on subsequent authors and to what extent the "memes" influence contemporary or future authors within and outside established research schools of thought. Ergographic analysis is an ongoing project that learns its rules by trying and doing. It links the forefront of research to the task of the science historian who is looking back over considerable distances. Ergographists try to speed up this process by the tools of analyzing working patterns and hopefully finding similarities and signs of influences in other schools of thought. In the virtual absence of suitable critical electronic software with semantic resolution power, ergography is still a matter of personal enterprise, curiosity, intuition, and willingness to follow with a prepared mind the paths investigated before by ingenious talent and make them more transparent.

In 2013 Allium cepa bulbs from different fields in Northern and Southern Germany, seeds and sets from onion breeders were analysed for infestation with Fusarium species. The same investigation was done in 2014 with different edible Allium spp. from local markets. Different Fusarium spp. were isolated and identified by morphological characterisation. 24 different Fusarium spp. were identified. The diversity of Fusarium spp. and the intensity of infestation was higher on edible bulbs compared to the younger sets and seeds. The analysed onions and other edible Allium spp. from local markets showed also high contents of different Fusarium species. The most prevalent identified Fusarium sp. in the analysed Allium spp. in Germany was Fusarium oxysporum which can cause the Fusarium Basal Rot, followed by Fusarium solani. Fusarium proliferatum, which can cause the Fusarium Salmon Blotch in onions, could be detected in about half of the sampled onion fields and in approximately 10% of all analysed onions from fields. Also in the onion sets, on the surface of the seeds and in other edible Allium spp. F. proliferatum could be identified. Besides F. proliferatum, further mycotoxin producing Fusarium spp. like Fusarium equiseti or Fusarium tricinctum were identified. Other Fusarium spp. like Fusarium sporotrichioides and Fusarium poae were first described in Allium sp. in this study. The two most prevalent Fusarium spp. F. oxysporum and F. solani are able to produce mycotoxins like enniatins, fumonisins, moniliformin and T-2 toxins. Fusarium sp. like F. proliferatum, F. equiseti and F. tricinctum are able to produce additional toxins like beauvericins, zearalenone and diacetoscirpenol. This high number of Fusarium spp., which are able to produce a broad spectrum of different mycotoxins, could be a potential health risk for human beings and livestock.

Septoria tritici blotch caused by Mycosphaerella graminicola (anamorph: Zymoseptoria tritici) is currently the most devastating disease on wheat crops worldwide, especially in regions with suitable climate conditions such as Western Europe. Pathogen control relies mainly on the use of fungicides and resistant cultivars. However, the durability of chemical and genetic control strategies is increasingly compromised in the field since the fungus frequently develops resistance to fungicides and overcomes host resistance. Here, we assessed the association between pathogenicity and fungicide tolerance in eighteen different M. graminicola strains isolated in 2009 from Northern France. These strains were chosen because they exhibited in preliminary experiments a wide range of in vitro tolerance levels against six demethylation inhibitors (epoxiconazole, cyproconazole, fluquinconazole, propiconazole, prothioconazole and pyrefenox). Inoculation of the Scorpion susceptible wheat cultivar in the greenhouse with these strains revealed a great variability in their pathogenicity levels (disease symptoms ranged from 0 to 66% of leaf area bearing pycnidia). Interestingly, strains with high fungicide tolerance levels caused overall the highest disease symptoms (45% of diseased leaf area on average) when compared to those with low fungicide tolerance levels (22% of diseased leaf area on average), thus confirming the association between pathogenicity level and fungicide tolerance in M. graminicola. The occurrence and selection in the field of fungal genotypes combining both pathogenicity and fungicide resistance should be taken into account in disease management strategies.

In order to find relationships between weed species distribution and soil pH, calcium carbonate (CaCO₃), electrical conductivity (EC), and organic matter percentage (OM %), fields surveys were done in 50 wheats (Triticum aestivum L.) fields of Uremia county (one of the northwest counties of Iran) in 2013. Data sampling of weeds was conducted from the beginning of stem elongation until the end of heading stages of wheat. In each field, 20 quadrates (0.25 m²) were randomly placed along a "W" pattern (5 quadrates in each line of this pattern) and in each quadrat, weed species were coded and recorded (density and cover percentage) for subsequent data entry and analysis. Canonical correspondence analysis (CCA) was used to find relationships between presence and absence of weeds in wheat fields and some of soil parameters. A total 169 weed species belonging to 35 plant families were recorded. CCA showed that four soil factors including soil pH, calcium carbonate (CaCO3), electrical conductivity (EC), and organic matter percentage (OM %) showed 58.6 percentage of weed species distribution variance. Abutilon theophrasti Medicus, Datura stramonium L., Malva neglecta Wallr., Portulaca oleracea L., Sisymbrium irio L., Atriplex patulum (L.). Aellen., and Heliotropium europaeum L. had maximum correlation with soil's pH. Euphorbia peplus L. and Salvia spinosa L. had negative correlation with pH, so that increasing pH caused reduction in the presence of these weeds. The presence of Chondrilla juncea L., Lepidium perfoliatum L., and Turgenia latifolia (L.) Hoff in the center of CCA biplot indicated that these weeds were correlated with all of these soil parameters.

Crop protection is mainly achieved by applying Plant Protection Products (PPP) using hydraulic nozzles, which rely on pressure, to produce a wide droplet size distribution. Because of always increased concerns about drift reduction, a wider range of low drift nozzles, such as air induction nozzles, was adopted in order to reduce the finest part of the spray. While successful for some treatments, the efficiency of coarser sprays is dramatically reduced on small and superhydrophobic target, i.e. at early stage weed control. This may be related to the increased proportion of big bouncing and splashing droplets. On the other hand, Controlled Droplet Application (CDA), using shielded rotary atomizers, stands for an improved control of droplets diameters and trajectories compared to hydraulic nozzles. Unfortunately, these atomizers, because of their horizontal droplet release, are widely recognized to produce more drift than hydraulic nozzles. The present contribution investigates whether the setting of a rotary atomizer 60 degrees forward tilted can reduce drift to acceptable levels in comparison with vertical and 60 degrees forward tilted standard and low drift flat fan nozzles for the same flow rate. In a wind tunnel, the drift potential of a medium spray produced by a tilted shielded rotary atomizer Micromax 120 was benchmarked with that of a flat fan nozzle XR11002 fine spray and that of an anti-drift nozzle Hardi Injet 015 medium spray. Operating parameters were set to apply 0.56 l/min for every spray generator. Vertical drift profiles were measured 2.0 m downward from nozzle axis for a 2 m.s(-1) wind speed. The tilted hydraulic nozzles resulted in a significant drift increase while droplets trajectories are affected by the decrease of the droplet initial vertical speed. Droplets emitted by the shielded rotary atomizer drift due to low entrained air and turbulence. A significant reduction of the cumulative drift was achieved by the rotary atomizer in comparison with flat fan nozzle while still being higher than the anti-drift nozzle. Unfortunately, the drift potential index (DIX) revealed that the cumulative drift reduction may not results in actual drift decrease because of higher drift at higher sampling locations. As a result, the DIX of the shielded rotary atomizer was similar to the standard flat-fan nozzle while the anti-drift nozzle reduced drastically drift as intended. Therefore, the 60 degrees tilted rotary atomizer failed to reach low drift levels as expected despite the reduced span.