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Field trials were conducted during 2008 – 2010 to evaluate weed control in dormant alfalfa (Medicago sativa L.) with metribuzin, imazetapyr and pronamide. The weed population in all experimental years was consisted mainly of annual winter and spring grass and broadleaf weeds, and some perennial weeds. The number of weed species and weed density increased with the years of alfalfa growing, from second to the fourth year. Weed density in the untreated control plots was 201.0, 217.2 and 240.5 plants per m2 in 2008, 2009 and 2010, respectively. The most dominant weeds were Anthemis cotula, Capsell bursa-pastoris and Taraxacum officinale in 2008, Alopecurus myosuroides and Poa pratensis in 2009 and Millium vernale and Arabidopsis thaliana in 2010. Efficacy of herbicides in control of weeds was ranged of 91.8% (pronamide) to 98.4% (metribuzin 1.0 kg*ha-1) in 2008, 93.1% (imazetapyr) to 97.3% (metribuzin 1.0 kg*ha-1) in 2009 and 92.1% (imazetapyr) to 97.3% (metribuzin 1.0 kg*ha-1) in 2010, respectively. Efficacy of herbicides in control of prevailing weeds during the 3 years field trial period was ranged of 48.5% to 100.0%. No visual alfalfa injured was determined by any rates during the experimental period, and consequently, none of the applied herbicides reduced first-harvest alfalfa yields. Alfalfa yield was markedly affected by herbicide efficacy in all experimental years, particularly in the second year, where yields of herbicide treatments were similar to that of the weed free control. © 2017, University of Zagreb - Faculty of Agriculture. All right reserved.

Costa C.,Italian Agricultural Research Council | Buchler R.,Bee Institute | Berg S.,Bayerische Landesanstalt fur Weinbau und Gartenbau | Bienkowska M.,Research Institute of Horticulture | And 23 more authors.
Journal of Apicultural Science | Year: 2012

An international experiment to estimate the importance of genotype-environment interactions on vitality and performance of honey bees and on colony losses was run between July 2009 and March 2012. Altogether 621 bee colonies, involving 16 different genetic origins of European honey bees, were tested in 21 locations spread in 11 countries. The genetic strains belonged to the subspecies A. m. carnica, A. m. ligustica, A. m. macedonica, A. m. mellifera, A. m. siciliana. At each location, the local strain of bees was tested together with at least two "foreign" origins, with a minimum starting number of 10 colonies per origin. The common test protocol for all the colonies took into account colony survival, bee population in spring, summer and autumn, honey production, pollen collection, swarming, gentleness, hygienic behaviour, Varroa destructor infestation, Nosema spp. infection and viruses. Data collection was performed according to uniform methods. No chemical treatments against Varroa or other diseases were applied during the experiment. This article describes the details of the experiment set-up and the work protocol.

Hatjina F.,Hellenic Institute of Apiculture | Costa C.,Italian Agricultural Research Council | Buchler R.,Bee Institute | Uzunov A.,Faculty for Agricultural Science and Food | And 21 more authors.
Journal of Apicultural Research | Year: 2014

Adaptation of honey bees to their environment is expressed by the annual development pattern of the colony, the balance with food sources and the host - parasite balance, all of which interact among each other with changes in the environment. In the present study, we analyse the development patterns over a period of two years in colonies belonging to 16 different genotypes and placed in areas grouped within six environmental clusters across Europe. The colonies were maintained with no chemical treatment against varroa mites. The aim of the study was to investigate the presence of genotype - environment interactions and their effects on colony development, which we use in this study as a measure of their vitality. We found that colonies placed in Southern Europe tend to have lower adult bee populations compared to colonies placed in colder conditions, while the brood population tends to be smaller in the North, thus reflecting the shorter longevity of bees in warmer climates and the shorter brood rearing period in the North. We found that both genotype and environment significantly affect colony development, and that specific adaptations exist, especially in terms of adult bee population and overwintering ability. © IBRA 2014 .

Buchler R.,Bee Institute | Costa C.,Italian Agricultural Research Council | Hatjina F.,Hellenic Institute of Apiculture | Andonov S.,Faculty for Agricultural Science and Food | And 15 more authors.
Journal of Apicultural Research | Year: 2014

The survival and performance of 597 honey bee colonies, representing five subspecies and 16 different genotypes, were comparatively studied in 20 apiaries across Europe. Started in October 2009, 15.7% of the colonies survived without any therapeutic treatment against diseases until spring 2012. The survival duration was strongly affected by environmental factors (apiary effects) and, to a lesser degree, by the genotypes and origin of queens. Varroa was identified as a main cause of losses (38.4%), followed by queen problems (16.9%) and Nosema infection (7.3%). On average, colonies with queens from local origin survived 83 days longer compared to non-local origins (p < 0.001). This result demonstrates strong genotype by environment interactions. Consequently, the conservation of bee diversity and the support of local breeding activities must be prioritised in order to prevent colony losses, to optimize a sustainable productivity and to enable a continuous adaptation to environmental changes. © IBRA 2014.

Van Der Zee R.,Netherlands Center for Bee Research | Pisa L.,Netherlands Center for Bee Research | Andonov S.,Faculty for Agricultural Science and Food | Brodschneider R.,University of Graz | And 33 more authors.
Journal of Apicultural Research | Year: 2012

In 2008 the COLOSS network was formed by honey bee experts from Europe and the USA. The primary objectives set by this scientific network were to explain and to prevent large scale losses of honey bee (Apis mellifera) colonies. In June 2008 COLOSS obtained four years support from the European Union from COST and was designated as COST Action FA0803 - COLOSS (Prevention of honey bee COlony LOSSes). To enable the comparison of loss data between participating countries, a standardized COLOSS questionnaire was developed. Using this questionnaire information on honey bee losses has been collected over two years. Survey data presented in this study were gathered in 2009 from 12 countries and in 2010 from 24 countries. Mean honey bee losses in Europe varied widely, between 7-22% over the 2008-9 winter and between 7-30% over the 2009-10 winter. An important finding is that for all countries which participated in 2008-9, winter losses in 2009-10 were found to be substantially higher. In 2009-10, winter losses in South East Europe were at such a low level that the factors causing the losses in other parts of Europe were absent, or at a level which did not affect colony survival. The five provinces of China, which were included in 2009-10, showed very low mean (4%) A. mellifera winter losses. In six Canadian provinces, mean winter losses in 2010 varied between 16-25%, losses in Nova Scotia (40%) being exceptionally high. In most countries and in both monitoring years, hobbyist beekeepers (1-50 colonies) experienced higher losses than practitioners with intermediate beekeeping operations (51-500 colonies). This relationship between scale of beekeeping and extent of losses effect was also observed in 2009-10, but was less pronounced. In Belgium, Italy, the Netherlands and Poland, 2008-9 mean winter losses for beekeepers who reported 'disappeared' colonies were significantly higher compared to mean winter losses of beekeepers who did not report 'disappeared' colonies. Mean 2008-9 winter losses for those beekeepers in the Netherlands who reported symptoms similar to "Colony Collapse Disorder" (CCD), namely: 1. no dead bees in or surrounding the hive while; 2. capped brood was present, were significantly higher than mean winter losses for those beekeepers who reported 'disappeared' colonies without the presence of capped brood in the empty hives. In the winter of 2009-10 in the majority of participating countries, beekeepers who reported 'disappeared' colonies experienced higher winter losses compared with beekeepers, who experienced winter losses but did not report 'disappeared' colonies. © IBRA 2012.

Buchler R.,Bee Institute | Andonov S.,Faculty for Agricultural Science and Food | Bienefeld K.,Landerinstitut fur Bienenkunde Hohen Neuendorf e.V. | Costa C.,Italian Agricultural Research Council | And 6 more authors.
Journal of Apicultural Research | Year: 2013

Here we cover a wide range of methods currently in use and recommended in modern queen rearing, selection and breeding. The recommendations are meant to equally serve as standards for both scientific and practical beekeeping purposes. The basic conditions and different management techniques for queen rearing are described, including recommendations for suitable technical equipment. As the success of breeding programmes strongly depends on the selective mating of queens, a subchapter is dedicated to the management and quality control of mating stations. Recommendations for the handling and quality control of queens complete the queen rearing section. The improvement of colony traits usually depends on a comparative testing of colonies. Standardized recommendations for the organization of performance tests and the measurement of the most common selection characters are presented. Statistical methods and data preconditions for the estimation of breeding values which integrate pedigree and performance data from as many colonies as possible are described as the most efficient selection method for large populations. Alternative breeding programmes for small populations or certain scientific questions are briefly mentioned, including also an overview of the young and fast developing field of molecular selection tools. Because the subject of queen rearing and selection is too large to be covered within this paper, plenty of references are given to facilitate comprehensive studies. Copyright © IBRA 2013.

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