Managed honey bee colony losses are of concern in the USA and globally. This survey, which documents the rate of colony loss in the USA during the 2015-2016 season, is the tenth report of winter losses, and the fifth of summer and annual losses. Our results summarize the responses of 5725 valid survey respondents, who collectively managed 427,652 colonies on 1 October 2015, an estimated 16.1% of all managed colonies in the USA. Responding beekeepers reported a total annual colony loss of 40.5% [95% CI 39.8-41.1%] between 1 April 2015 and 1 April 2016. Total winter colony loss was 26.9% [95% CI 26.4-27.4%] while total summer colony loss was 23.6% [95% CI 23.0-24.1%], making this the third consecutive year when summer losses have approximated to winter losses. Across all operation types, 32.3% of responding beekeepers reported no winter losses. Whilst the loss rate in the winter of 2015-2016 was amongst the lowest winter losses recorded over the ten years this survey has been conducted, 59.0% (n = 3378) of responding beekeepers had higher losses than they deemed acceptable. Encuesta nacional 2015-2016 sobre pé rdidas anuales de colonias de la abeja de la miel manejada en los EE.UU Las pérdidas de colonias de abejas manejadas son preocupantes en los Estados Unidos y en el mundo. Esta encuesta, que documenta la tasa de pérdida de colonias en los EE.UU. durante la temporada 2015-2016, es el décimo informe de las pérdidas de invierno, y el quinto de las pérdidas de verano y anuales. Nuestros resultados resumen las respuestas de 5.725 encuestados válidos, quienes colectivamente manejaron 427.652 colonias el 1 de octubre de 2015, un 16.1% de todas las colonias manejadas en los Estados Unidos. Los apicultores respondieron con una pérdida total de colonias anual del 40.5% [IC del 95%: 39.8-41.1%] entre el 1 de abril de 2015 y el 1 de abril de 2016. La pérdida total de colonias de invierno fue del 26.9% [IC del 95%: 26.4-27.4%], y las de verano del 23.6% [IC del 95%: 23.0-24.1%], lo que lo convierte en el tercer año consecutivo en que las pérdidas del verano se han aproximado a las pérdidas de invierno. En todos los tipos de operaciones, el 32.3% de los apicultores que respondieron no reportaron pérdidas de invierno. Mientras que la tasa de pérdidas en el invierno de 2015-2016 fue una de las pérdidas de invierno más bajas registradas durante los diez años que se han realizado esta encuesta, el 59.0% (n = 3.378) de los apicultores que respondieron tuvieron mayores pérdidas de las que consideraban aceptables.

Fire has a major impact on the structure and function of many ecosystems globally. Pyrodiversity, the diversity of fires within a region (where diversity is based on fire characteristics such as extent, severity, and frequency), has been hypothesized to promote biodiversity, but changing climate and land management practices have eroded pyrodiversity. To assess whether changes in pyrodiversity will have impacts on ecological communities, we must first understand the mechanisms that might enable pyrodiversity to sustain biodiversity, and how such changes might interact with other disturbances such as drought. Focusing on plant-pollinator communities in mixed-conifer forest with frequent fire in Yosemite National Park, California, we examine how pyrodiversity, combined with drought intensity, influences those communities. We find that pyrodiversity is positively related to the richness of the pollinators, flowering plants, and plant-pollinator interactions. On average, a 5% increase in pyrodiversity led to the gain of approximately one pollinator and one flowering plant species and nearly two interactions. We also find that a diversity of fire characteristics contributes to the spatial heterogeneity (b-diversity) of plant and pollinator communities. Lastly, we find evidence that fire diversity buffers pollinator communities against the effects of drought-induced floral resource scarcity. Fire diversity is thus important for the maintenance of flowering plant and pollinator diversity and predicted shifts in fire regimes to include less pyrodiversity compounded with increasing drought occurrence will negatively influence the richness of these communities in this and other forested ecosystems. In addition, lower heterogeneity of fire severity may act to reduce spatial turnover of plantpollinator communities. The heterogeneity of community composition is a primary determinant of the total species diversity present in a landscape, and thus, lower pyrodiversity may negatively affect the richness of plant-pollinator communities across large spatial scales.

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Honey bee colony losses in the US have exceeded acceptable levels for at least a decade, leaving beekeepers in need of management practices to improve colony health and survival. Here, an empirical Best Management Practice (BMP) regimen was tested, comprised of the top four management practices associated with reduced colony mortality in backyard beekeeping operations according to Bee Informed Partnership Loss and Management survey results. Seven study locations were established across the US, and each location consisted of ten colonies treated according to empirical BMPs and ten according to average beekeeping practice. After 3 years, colonies treated according to empirical BMPs experienced reduced Varroa infestation, viral infection, and mortality compared to colonies managed with Average practices. In addition, BMP colonies produced more new colonies via splits. The colonies under Average practices were given chemical Varroa treatments only once per year, and thus spent more months above economic threshold of 3.0 mites/100 bees. Increased time spent above the economic threshold was significantly correlated to both increased viral infection and colony mortality. This study demonstrates the cumulative effects of management and colony health stressors over months and years, especially the dire importance of regular Varroa monitoring and management.

There exists a lack of control efficacy information to enable decision-making about which organic insecticide product works best for a given insect pest. Here, we summarize results of 153 field trials on the control efficacy of common active ingredients in organic insecticides against 12 groups of the most difficult to control insect pests. These trials evaluated primarily the organic products Entrust (spinosad), Azera (pyrethrin and azadirachtin), PyGanic (pyrethrin) and Neemix (azadirachtin), which reduced pest infestations by an overall 73.9%, 61.7%, 48.6% and 46.1% respectively, averaged across all trials. Entrust was the most effective control option for many insect pests, particularly providing >75% control of flea beetles, Colorado potato beetle, cabbageworms and alfalfa weevil, but was relatively ineffective against true bugs and aphids. Azera provided >75% control of green peach aphid, flea beetles, Japanese beetle, Mexican bean beetle, potato leafhopper and cabbageworms. PyGanic was less effective than Entrust and Azera but still provided >75% control of green peach aphid, flea beetles and potato leafhopper. The growth inhibition effects of azadirachtin in Neemix were particularly effective against larvae of Mexican bean beetle and Colorado potato beetle but was generally less effective in trials with insect infestations consisting mainly of adult stages. Those insect pests that were particularly difficult to control included thrips, stinkbugs, cucumber beetles and fruitworms. Several caveats pertaining to the application of the results are discussed.