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Devarrewaere W.,Catholic University of Leuven | Foque D.,Belgium Institute for Agricultural and Fisheries Research | Heimbach U.,Institute for Plant Protection in Field Crops and Grassland | Cantre D.,Catholic University of Leuven | And 3 more authors.
Environmental Science and Technology | Year: 2015

Crop seeds are often treated with pesticides before planting. Pesticide-laden dust particles can be abraded from the seed coating during planting and expelled into the environment, damaging nontarget organisms. Drift of these dust particles depends on their size, shape and density. In this work, we used X-ray micro-CT to examine the size, shape (sphericity) and porosity of dust particles from treated seeds of various crops. The dust properties quantified in this work were very variable in different crops. This variability may be a result of seed morphology, seed batch, treatment composition, treatment technology, seed cleaning or an interaction of these factors. The intraparticle porosity of seed treatment dust particles varied from 0.02 to 0.51 according to the crop and generally increased with particle size. Calculated settling velocities demonstrated that accounting for particle shape and porosity is important in drift studies. For example, the settling velocity of dust particles with an equivalent diameter of 200 μm may vary between 0.1 and 1.2 m s-1, depending on their shape and density. Our analysis shows that in a wind velocity of 5 m s-1, such particles ejected at 1 m height may travel between 4 and 50 m from the source before settling. Although micro-CT is a valuable tool to characterize dust particles, the current image processing methodology limits the number of particles that can be analyzed. © 2015 American Chemical Society. Source


Chen Y.F.,Hubei Academy of Agricultural Science | Mekete T.,University of Florida | Dababat A.A.,International Maize and Wheat Improvement Center | Daub M.,Institute for Plant Protection in Field Crops and Grassland | And 2 more authors.
Helminthologia (Poland) | Year: 2014

The study assessed the impact on the soil nematodes during the first 3-years after reclamation of a brown coal mining area. Samples were taken from 5 fields: 1 year before excavation, right at the beginning of reclamation (Yr 0), and in fields 1, 2 and 3 years after reclamation. A total of 31 families of nematodes were recorded and the nematode community of field Yr 0 was significantly different from that of other four sampling sites. Nematode abundance decreased after excavation and then began to return to initial community levels at each of the three reclamation sites with bacterivore nematodes recovering faster than the fungivores, omnivore-predators or the plant parasites. A gradual but consistent regeneration of the nematode community to its original structure was seen from the beginning of sampling and this recovery process was detectable over the three successive years of experimentation. Open-pit mining, therefore, drastically disturbed nematode community structure initially but the community was able to recover and stabilized quickly after reclamation. © 2014 Versita Warsaw and Springer-Verlag Wien. Source


Westphal A.,Institute for Plant Protection in Field Crops and Grassland
Journal of Nematology | Year: 2011

Physical, chemical, and biological factors of soil may reduce damage caused by plant-parasitic nematodes. Suppression of plant-parasitic nematodes is particularly challenging in soils in which there are short crop sequences, sequential susceptible host crops, or infestations of multiple nematode species. In southern Indiana, a watermelon production system involving rotations with soybean and corn does not suppress Meloidogyne incognita, but several aspects of such systems can be modified to reduce nematode damage in an integrated management approach. Cash crops with resistance to M. incognita can be used to reduce population densities of M. incognita. Small grains as cover crops can be replaced by cover crops with resistance to M. incognita or by crops with biofumigation potential. Mycorrhizal fungal inoculations of potting mixes during transplanting production of watermelon seedlings may improve early crop establishment. Other approaches to nematode management utilize soil suppressiveness. One-year rotations of soybean with corn neither reduced the soil-bome complex of sudden death syndrome (SDS) nor improved soybean root health over that in soybean monoculture. Reduced tillage combined with crop rotation may reduce the activity of soil-borne pathogens in some soils. For example in a long-term trial, numbers of Heterodera glycines and severity of foliar SDS symptoms were reduced under minimum tillage. Thus, sustainable management strategies require holistic approaches that consider entire production systems rather than focus on a single crop in its year of production. © The Society of Nematologists 2011. Source


Lindner K.,Institute for Plant Protection in Field Crops and Grassland | Haase N.U.,Federal Research Institute of Nutrition and Food | Roman M.,Fangmeier Agro Impex | Seemuller E.,Institute for Plant Protection in Fruit Crops and Viticulture
Potato Research | Year: 2011

Potato stolbur is a phytoplasmal disease that seriously affects yield and tuber quality in South Eastern Europe, Russia and the Mediterranean areas. In 2007 and 2008, field experiments were carried out to determine stolbur resistance of processing potato cultivars at Sannicolau Mare (Romania) by determining consistency and concentration of reducing sugars (fructose and glucose), sucrose and phytoplasmas in potato tubers. In both years, non-symptomatic potato tubers showed sucrose levels in the range of 3,000 mg kg -1 fresh weight (FW). In contrast, sucrose concentrations were up to 11,820 mg kg -1 FW in 2007 and 19,560 mg kg -1 FW in 2008 in tubers showing severe symptoms. These high values severely affect suitability of tubers for processing as sucrose serves as substrate for the formation of reducing sugars that are the limiting factor in fried potato production for Maillard-related discolouration. The cultivars examined differed considerably in susceptibility to stolbur disease. Whereas cvs. 'Courage' and 'Lady Rosetta' showed high numbers of diseased tubers and high sucrose concentrations, 'Lady Claire' had a lower incidence of symptomatic tubers and lower sucrose concentrations. However, fully resistant cultivars were not observed. Across all cultivars examined, phytoplasmal concentration was significantly higher in symptomatic tubers than in non-symptomatic ones. © 2011 EAPR. Source


Lindner K.,Institute for Plant Protection in Field Crops and Grassland | Trautwein F.,Coordination Center for the Ministry of Food and Agriculture | Kellermann A.,Institute for Crop Science and Plant Breeding | Bauch G.,Institute for Crop Science and Plant Breeding
Journal of Plant Diseases and Protection | Year: 2015

In the EU and many other countries worldwide, seed potatoes require certification to be marketed. In most of the European national and international seed potato regulations, the tolerances for viruses are at present based on a combination of virus incidence and symptom severity. Historically all severe viruses were usually the origin of severe virus diseases, and mild viruses, in general, were seen to cause mild diseases. However, the situation has changed, especially for the most economically important virus, Potato virus Y (PVY), which is considered a severe virus. Investigation of PVY-infected potato leaf samples from Bavarian potato seed certification found that the “classical” O and the N strains, predominantly responsible for severe virus diseases, represented less than 1% of the infections present. Ca. 99% of the PVY infections were comprised of the new recombinant strains PVYNTN and PVYNW. The ratio between these recombinants differed substantially. Differences in susceptibility of particular cultivars to certain PVY strains seem to be one reason for that. Therefore, the ratio of the recombinants may depend upon which cultivars are favoured in different potato growing areas or countries. In greenhouse tests, PVYNTN and PVYNW were associated with both severe and mild disease symptoms. In corresponding field tests, the symptom severity differed considerably. Furthermore, there was no correlation detected between virus concentration and symptom severity. These results will contribute to a worldwide discussion on the elimination of the criterion virus symptom severity from potato seed certification during the forthcoming months. The discussion follows amendments made to international seed potato regulation documents. National regulations must be aligned by the EU member states until January 2016. © Eugen Ulmer KG, Stuttgart. Source

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