7850 research outputs found
Sort by
The implications of Panicum miliaceum in the viral epidemiology of cereals
Get PDFDie Echte Hirse (Panicum miliaceum L.) ist ein häufigeres Unkraut in Ungarn, das man meistens auf Maisfeldern findet, aber auch immer häufiger in anderen Kulturpflanzen wie Kartoffel, Weizen und anderem Getreide. Es kann sich wegen fehlender Dormanz weiter ausbreiten. Dieses Unkraut ist als Gras relativ nah mit Weizen verwandt, so dass es Ziel des Experiments war, zu untersuchen, welche Weizenviren Panicum miliaceum infizieren können.Fünfundvierzig Hirse-Blattproben wurden 2014 und 2015 auf Feldern in der Nähe von Keszthely (Kreis Zala) und 35 Blattproben im Jahr 2016 auch in der Nähe von Keszthely gesammelt. Die Proben wurden sofort eingefroren und bei -20°C gelagert. Die serologische Methode DAS ELISA wurde verwendet, um Weizenviren an den Blättern zu bestimmen.Unter den 80 gesammelten Blattproben gab es 27 positive Ergebnisse. Eine einfache Virusinfektion wurde in 20 Proben gefunden. 10-mal Weizenstreifen-Mosaikvirus (WSMV), 7-mal Weizenzwergvirus (WDV), 6-mal Gerste-Streifen-Mosaikvirus (BSMV), 5-mal Gerste-Gelb-Zwergvirus (BYDV) und 1-mal Brom-Streifen- Mosaikvirus (BStMV) wurde nachgewiesen. Brom-Mosaikvirus (BMV) wurde in 4 Proben nachgewiesen. Komplexe Infektionen wurden in 5 Proben festgestellt: In 3 Proben wurden WDV und WSMV, in einer WDV, WSMV und BYDV sowie in einer BMV-, WDV- und BYDV-Komplexinfektion identifiziert. Nach der ersten Untersuchung wurden weitere Proben gesammelt, um die Untersuchung fortzusetzen. Diese Ergebnisse zeigen, dass Hirse als Unkraut eine wichtige Rolle bei der Ausbreitung von Getreidevirusarten spielen kann.Common millet (Panicum miliaceum L.) is a spreading weed in Hungary, it can be found mostly on maize fields, but it has been investigated, that it is more and more often occurring in other cultivated plants, like potato, wheat, and other cereals. It can widely spread because of the lack of seed dormancy. This weed is a close relative to wheat, so the aim of the experiment was to investigate, which wheat viruses can infect of the common millet (Panicum miliaceum L.). Forty-five millet leaf samples were collected from fields in 2014 and 2015 near Keszthely, Zala County, and 35 leaf samples in 2016 near Keszthely. After the collection, the samples were immediately frozen and stored at - 20○C. The DAS ELISA serological method was used to determine wheat viruses from the leaves. Among the 80 collected leaf samples 27 gave positive results. Simple virus infection were realised in 20 samples. 10 times Wheat streak mosaic virus (WSMV), 7 times Wheat dwarf virus (WDV), 6 times Barley stripe mosaic virus (BSMV), 5 times Barley yellow dwarf virus (BYDV), and 1 time Brome streak mosaic virus (BStMV) was detected. Brome mosaic virus (BMV) was detected in 4 samples. Complex infections were detected in 5 samples: in 3 samples WDV and WSMV, and in 1 sample WDV, WSMV and BYDV, and in 1 sample BMV, WDV and BYDV. After the first investigation other samples were collected, in order to continue the examination. These results indicate that Panicum miliaceum can play a major role in the distribution of different cereal virus species
1.2 Three cardinal numbers to safeguard bees against pesticide exposure: LD50 , NOEC (revised) and the Haber exponent.
Get PDFRegulators often employ cardinal indicators to justify measures to protect the health of farmland bees from pesticides used in crop protection. Previously, in evaluating the likely hazard of a compound, they have made extensive use of its LD50 (‘lethal dose to 50% of exposed subjects’), and NOEC (‘no observable effect concentration’). Here, I argue that regulators should also use a third indicator, namely the Haber exponent. The Haber exponent qualifies the meaning of the LD50 by revealing the relative hazard of environmentally relevant exposures longer than that used to determine the LD50 originally. Additionally, I show how the experimental protocol used to determine the Haber exponent will also produce a well-founded, parametric value of the NOEC. Taken together, these three numbers establish a strong foundation on which to evaluate the potential impact of an agrochemical on bees.Regulators often employ cardinal indicators to justify measures to protect the health of farmland bees from pesticides used in crop protection. Previously, in evaluating the likely hazard of a compound, they have made extensive use of its LD50 (‘lethal dose to 50% of exposed subjects’), and NOEC (‘no observable effect concentration’). Here, I argue that regulators should also use a third indicator, namely the Haber exponent. The Haber exponent qualifies the meaning of the LD50 by revealing the relative hazard of environmentally relevant exposures longer than that used to determine the LD50 originally. Additionally, I show how the experimental protocol used to determine the Haber exponent will also produce a well-founded, parametric value of the NOEC. Taken together, these three numbers establish a strong foundation on which to evaluate the potential impact of an agrochemical on bees
1.4 Honey bee nectar foragers feeding themselves and the colony: a review in support of dietary exposure assessment
Get PDFQuantitative knowledge regarding the foods collected and ingested by nectar foraging honey bees (Apis mellifera) is essential for accurately assessing risk associated with pesticide residues in their diet. Although a very large and diverse body of research is available covering many years of research in the literature, much of this research was designed for purposes other than risk assessment and the accumulated knowledge has not been comprehensively reviewed and consolidated from the viewpoint of pesticide risk assessment. Accordingly, in the interest of advancing all tiers of pollinator risk assessment, and identifying data gaps, we strove to gather, assess, and summarize quantitative data relating to nectar forager collection, consumption and sharing of nectar within the colony. Data pertaining to nectar forager provisioning before foraging flights, quantities of nectar brought back to the hive, frequency and duration of foraging trips and energetics was reviewed. Recommendations for future research in support of refined honey bee risk assessment will be discussed.Quantitative knowledge regarding the foods collected and ingested by nectar foraging honey bees (Apis mellifera) is essential for accurately assessing risk associated with pesticide residues in their diet. Although a very large and diverse body of research is available covering many years of research in the literature, much of this research was designed for purposes other than risk assessment and the accumulated knowledge has not been comprehensively reviewed and consolidated from the viewpoint of pesticide risk assessment. Accordingly, in the interest of advancing all tiers of pollinator risk assessment, and identifying data gaps, we strove to gather, assess, and summarize quantitative data relating to nectar forager collection, consumption and sharing of nectar within the colony. Data pertaining to nectar forager provisioning before foraging flights, quantities of nectar brought back to the hive, frequency and duration of foraging trips and energetics was reviewed. Recommendations for future research in support of refined honey bee risk assessment will be discussed
1.16 Sensitivity of honey bee larvae to plant protection products and impact of EFSA bee guidance document
Get PDFIn addition to other assessments, the 2013 EFSA bee guidance document requires the risk assessment of plant protection products on honey bee larvae. At the time the EFSA document was finalized, no data on honey bee larvae were available. In 2013 ECPA (the European Crop Protection Association) perfomed an impact analysis of the (then) new EFSA risk assessment and the reliability of the outcomes, using estimated endpoints derived from acute oral honey bee tests together with the usual extrapolation factors. Today, a number of honey bee larvae toxicity studies have been conducted according to the newly developed testing methods for single exposure (OECD TG 237) and repeated exposure testing (OECD GD 239). These experimental data have been used to update the ECPA impact analysis. Data on 114 active substances or formulated products were used, covering 166 worst case uses; (58 herbicides, 53 fungicides, 47 insecticides and 8 PGRs). The “pass” rates were determined according to the EFSA Bee guidance document and compared with the original outcome of the impact analysis from 2013 and with adult chronic toxicity data. When the findings of the impact analysis based on experimental data from 22 day larval tests was compared with the impact analysis from 2013 based on extrapolated data the two gave very similar results, thus indicating that the original assessment using acute data and extrapolation factors was suitably predictive.In addition to other assessments, the 2013 EFSA bee guidance document requires the risk assessment of plant protection products on honey bee larvae. At the time the EFSA document was finalized, no data on honey bee larvae were available. In 2013 ECPA (the European Crop Protection Association) perfomed an impact analysis of the (then) new EFSA risk assessment and the reliability of the outcomes, using estimated endpoints derived from acute oral honey bee tests together with the usual extrapolation factors. Today, a number of honey bee larvae toxicity studies have been conducted according to the newly developed testing methods for single exposure (OECD TG 237) and repeated exposure testing (OECD GD 239). These experimental data have been used to update the ECPA impact analysis. Data on 114 active substances or formulated products were used, covering 166 worst case uses; (58 herbicides, 53 fungicides, 47 insecticides and 8 PGRs). The “pass” rates were determined according to the EFSA Bee guidance document and compared with the original outcome of the impact analysis from 2013 and with adult chronic toxicity data. When the findings of the impact analysis based on experimental data from 22 day larval tests was compared with the impact analysis from 2013 based on extrapolated data the two gave very similar results, thus indicating that the original assessment using acute data and extrapolation factors was suitably predictive
3.1 Which endpoints can reliably be assessed in semi-field and field pollinator species testing without estimating false positive or false negative? MDD’s and replicates issue
Get PDF3.6 Non-uniform distribution of treated sucrose solution via trophallaxis by honeybees affects homing success variability and mortality
Get PDFBackground: Food sharing in a group via trophallaxis might lead to a non-uniform distribution of pesticide spiked sucrose solution between caged honeybees. This can cause high variability in the homing success rate or mortality among group members and treatment replicates. In order to improve the oral food distribution of tested sucrose solution we compared two feeding schemes with two or ten bees per cage (20 μL/bee) and evaluated the impact on homing success rate and mortality. Results: First results showed that food intake with the two-bees feeding regime is faster. Therefore, a more accurate dosing distribution among bees can be expected. We measured a less variable homing success rate and retuning time among runs and the corresponding treatments. Furthermore, mortality rate of the groupfeeding scheme with ten bees per cage resulted in higher mortality values when compared to the two-bees feeding scheme. This might be an indication for a better and more uniform distribution of the treated sucrose solution among two caged bees.Conclusion: Improving the uniform distribution of test items by orally treatment administration in smaller groups with honeybees should be discussed and considered, as toxicity endpoints of single-dosed wild bees are compared with group-dosed honeybees. Furthermore, to minimize the trophallaxis dependency regarding food distribution in group dosed honeybees.Background: Food sharing in a group via trophallaxis might lead to a non-uniform distribution of pesticide spiked sucrose solution between caged honeybees. This can cause high variability in the homing success rate or mortality among group members and treatment replicates. In order to improve the oral food distribution of tested sucrose solution we compared two feeding schemes with two or ten bees per cage (20 μL/bee) and evaluated the impact on homing success rate and mortality. Results: First results showed that food intake with the two-bees feeding regime is faster. Therefore, a more accurate dosing distribution among bees can be expected. We measured a less variable homing success rate and retuning time among runs and the corresponding treatments. Furthermore, mortality rate of the groupfeeding scheme with ten bees per cage resulted in higher mortality values when compared to the two-bees feeding scheme. This might be an indication for a better and more uniform distribution of the treated sucrose solution among two caged bees.Conclusion: Improving the uniform distribution of test items by orally treatment administration in smaller groups with honeybees should be discussed and considered, as toxicity endpoints of single-dosed wild bees are compared with group-dosed honeybees. Furthermore, to minimize the trophallaxis dependency regarding food distribution in group dosed honeybees
5.1 Large-scale monitoring of effects of clothianidin dressed OSR seeds on pollinating insects in Northern Germany: Effects on large earth bumblebees (Bombus terrestris)
Get PDF5.6 Residues in bee-relevant matrices
Get PDFApplication of pesticides during flowering of crops can result in exposure of pollinating insects such as honey bees, bumble bees and wild bees. In addition, residues of pesticides in bee products like honey may result from such applications. One of the overall goals of the German "FitBee" project was to determine the transport of plant protection products into the honey bee colony via individual bees and reduce the exposure to plant protection products by application technology approaches. One of these application technologies is DroplegUL, with which row crops can be sprayed underneath the canopy level, avoiding spray onto the blossoms. In the scope of the "FitBee" project (2011 to 2015), we conducted during five years semi-field experiments in Germany comparing conventional and DroplegUL spraying techniques regarding their implications to honeybee colony exposure. In this context, various trials were conducted in which residues in in-hive matrices (stored nectar, pollen) of bee colonies foraging on a model crop (oilseed rape) which was pesticide-treated with DroplegUL vs. conventional technology were measured.Application of pesticides during flowering of crops can result in exposure of pollinating insects such as honey bees, bumble bees and wild bees. In addition, residues of pesticides in bee products like honey may result from such applications. One of the overall goals of the German "FitBee" project was to determine the transport of plant protection products into the honey bee colony via individual bees and reduce the exposure to plant protection products by application technology approaches. One of these application technologies is DroplegUL, with which row crops can be sprayed underneath the canopy level, avoiding spray onto the blossoms. In the scope of the "FitBee" project (2011 to 2015), we conducted during five years semi-field experiments in Germany comparing conventional and DroplegUL spraying techniques regarding their implications to honeybee colony exposure. In this context, various trials were conducted in which residues in in-hive matrices (stored nectar, pollen) of bee colonies foraging on a model crop (oilseed rape) which was pesticide-treated with DroplegUL vs. conventional technology were measured