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Amein T.,Box | Amein T.,Swedish University of Agricultural Sciences | Wright S.A.I.,University of Molise | Wikstrom M.,Jordbruksverket | And 10 more authors.
Journal of Plant Diseases and Protection | Year: 2011

Due to the lack of foliar fungicide use, the organic production of Brassica seeds free of Alternaria spp. is difficult. Therefore, effective seed treatments certified for use in organic farming are needed to eradicate or at least effectively reduce the seed-borne inoculum. We here report results of greenhouse and field experiments in which non-chemical seed treatments were tested for control of A. brassicicola on cabbage seeds naturally infested with the pathogen. In greenhouse experiments, significant improvements were obtained by seed treatment with some commercialised and experimental microbial biocontrol agents, an emulsion of thyme oil in water (0.1%) and by the tested physical seed treatments methods (i.e. hot water, aerated steam and electron seed treatment). Resistance inducers tended to increase the percentage of healthy plants, but the effects were statistically not significant. Generally the combination of physical treatments with the effective agents did not result in improved performance. Positive effects on crop establishment and yield by the same treatments were also observed in field tests. Overall the results indicate that several options for non-chemical control of A. brassicicola on Brassica seeds exist that are comparable in efficacy to the chemical standard Aatiram (active ingredient thiram) used in this study. © Eugen Ulmer KG, Stuttgart.


Koch E.,Institute for Biological Control | Schmitt A.,Institute for Biological Control | Stephan D.,Institute for Biological Control | Kromphardt C.,Institute for Strategies and Technology Assessment in Plant Protection | And 12 more authors.
European Journal of Plant Pathology | Year: 2010

The current study was initiated to evaluate the efficacy of physical methods (hot water, aerated steam, electron treatment) and agents of natural origin (resistance inducers, plant derived products, micro-organisms) as seed treatments of carrots for control of Alternaria dauci and A. radicina. Control of both Alternaria species by seed treatment with the resistance inducers was generally poor. Results were also not satisfactory with most of the formulated commercial micro-organism preparations. Based on the average of five field trials, one of these, BA 2552 (Pseudomonas chlororaphis), provided a low but significant increase in plant stand. Among the experimental micro-organisms, the best results were obtained with Pseudomonas sp. strain MF 416 and Clonostachys rosea strain IK726. A similar level of efficacy was provided by seed treatment with an emulsion (1%) of thyme oil in water. Good and consistent control was generally achieved with the physical methods aerated steam, hot water and electron treatment. Aerated steam treatment was, apart from the thiram-containing chemical standard, the best single treatment, and its performance may at least partially be due to extensive pre-testing, resulting in dosages optimally adapted to the respective seed lot. In some of the experiments the effect of the hot water treatment, which was tested at a fixed, not specifically adapted dosage, was significantly improved when combined with a Pseudomonas sp. MF 416 or C. rosea IK726 treatment. The results are discussed in relation to the outcome of experiments in which the same seed treatment methods and agents were tested in other seed-borne vegetable pathosystems. © 2010 KNPV.


Howard F.W.,University of Florida | Pemberton R.,U.S. Department of Agriculture | Schroer S.,Institute for Strategies and Technology Assessment in Plant Protection | Hodges G.,Florida State Collection of Arthropods
Florida Entomologist | Year: 2010

The lobate lac scale, Paratachardina pseudolobata Kondo & Gullan, attacks large numbers of plants in Florida. The scales primarily infest the branches and main stems <2 cm in diameter; rarely were they found on stems that were larger than 4 cm in diameter or on leaves and never on roots. They produce honeydew, but ants did not tend the scales nor did ants appear attracted to the honeydew, which is ejected from the scale instead of being present in collectable droplets. Males have not been found in Florida populations of the lobate lac scale and females are parthenogenetic and ovoviviparous. The scales developed into adult females in 1519 weeks. Crawlers of second generation were present 21 weeks after young crawlers of the previous generation were placed on a host plant. The pre-imaginal stadia were: first instar 811 weeks; second instar 78 weeks. The numbers of crawlers counted per month on host plants were notably uniform throughout the year, but there was evidence of a slight increase in crawler production during the warmer months. Lobate lac scales subjected to a simulated frost of -3°C had a low survival rate. In a test of survival without a host, one of 22 crawlers survived 14 d, and 3 of 32 survived 18 d. Based on the numbers of exit holes in mature female tests, the parasitism rate since this pest was found in Florida is not greater than 1%.


Sieber S.,Leibniz Center for Agricultural Landscape Research | Pannell D.,University of Western Australia | Muller K.,Leibniz Center for Agricultural Landscape Research | Holm-Muller K.,University of Bonn | And 2 more authors.
Land Use Policy | Year: 2010

A newly developed indicator of the pesticide risk for aquatic biocenosis in surface water bodies is applied within an economic sector model, and is used to evaluate alternative designs for an environmental policy programme. For rural districts ('Landkreise') across Germany, different widths of riparian buffer zones adjacent to surface water bodies are evaluated in terms of efficient cost/risk ratios. The indicator is defined as acute risk under worst-case input conditions and is based on combining a sectoral model, a national survey on pesticide use and a toxicological risk assessment model. The nation-wide survey provides data on pesticide use by agricultural crop. On this basis, crop-specific risk indices for aquatic biocenosis are calculated by means of eco-toxic criteria for indicator organisms and aggregated through crop patterns to the rural-district level. GIS is used to calculate the influences of natural site factors (e.g. soil types, land use distance to water bodies, etc.) on pesticide input in surface water and to calculate the regional risk potentials at regional level. An economic cost-impact analysis is conducted based on the new indicator. Opportunity costs of converting agricultural land to riparian buffer strips are estimated using the agricultural sector model RAUMIS, for buffer strip widths of 3, 30 and 50 m, as per the European the environmental programme EC 99/1257/EEC. These costs are then compared with estimated risk reduction potentials at the regional level of administrative districts. Results show that cost-impact ratios are most efficient for 3 m buffer strips and in those regions with the lowest costs from changing agricultural land use (e.g. through reduced livestock production). A major future research need in this area is a higher spatial resolution at the grid-level. © 2009 Elsevier Ltd. All rights reserved.


Pohl D.,Suleyman Demirel University of Turkey | Kuhne S.,Institute for Strategies and Technology Assessment in Plant Protection | Karaca I.,Suleyman Demirel University of Turkey | Moll E.,Institute for Strategies and Technology Assessment in Plant Protection
Phytoparasitica | Year: 2012

Greenhouses in Turkey under integrated pest management can be colonized by a high number predatory flies of the species Coenosia attenuata Stein, 1903 (Muscidae: Coenosia Meigen, 1826). Studies have shown that Coenosia predators do not simply colonize greenhouses from the outside for short periods but instead they are able to complete their developmental cycle in the greenhouse soil and can become established there for a long period of time. C. attenuata is indigenous to the Palaeotropical region. Its prey spectrum includes whiteflies, black fungus gnats and leaf-mining flies. Studies of the natural occurrence of these predaceous flies in greenhouses led to a recognition of the significance of this complex of beneficials for the control of important greenhouse pests. They can build up effective populations under greenhouse conditions, and as non-specific predators can feed on a variety of pest groups and on innocuous species. © 2011 Springer Science + Business Media B.V.

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