Bijen

Syngenta and Bayer Agree to Ban of 12 Bee-Harming Pesticides

Twelve pesticides made with chemicals shown to harm bees and other pollinators are slated to be banned as part of a proposed settlement with the manufacturers, the EPA announced Dec. 12. The pesticides, marketed by Syngenta AG., Bayer AG, and Valent USA Corp., contain either thiamethoxam or clothianidin, two chemicals in the neonicotinoid class that are linked to declining bee populations.

Wageningse experts over de oorzaken van bijensterfte vanaf 2009

Akkerwijzer in 2009: Sinds 2000 sterven bijen massaal. Bijonderzoeker Tjeerd Blacquière van Universiteit Wageningen, maakt zich zorgen over deze situatie. Imkers kennen het fenomeen dat bijenvolken sterven. Gemiddeld sterft 10 procent in de winter. De afgelopen jaren lag dat percentage hoger en fluctueert dit. Blacquière wijt de sterfte aan de varraomijt. Romeé van der Zee, bijendeskundige uit Tersoal, denkt dat Nosema ceranea, een soort schimmel, de boosdoener is. Een andere oorzaak van de afname van de bijenvolken is de vergrijzing van de imkers.

Truths about pesticides

Chemical agriculture is destroying the ecosystems that sustain all life. Pesticides are a key culprit in the decline of bees, butterflies and other pollinators — leading some scientists to warn of a “second silent spring.” , Pesticides wreak havoc on the soil by killing the organisms that are the basis of soil life. And they pollute rivers, lakes and oceans, leading to fish die-offs.

Fipronil blamed for historical bee deaths

Researchers in the UK report new evidence that the pesticide fipronil, not the neonicotinoid imidacloprid, caused a massive die-off of honey bees in France from 1994 to 1998. Both pesticides hit the market in the early 1990s. At the time, beekeepers and environmentalists largely blamed imidacloprid for the bee deaths. Now, Philippa Holder and colleagues at the University of Exeter and Fera Science, a UK public-private venture focused on agricultural science, suggest that fipronil used on sunflowers was more likely the culprit (Proc. Natl. Acad. Sci. U.S.A.

Imidacloprid Found to Make Bees Less Social

Scientists said they’ve found that exposure to the neonicotinoid pesticide imidacloprid produces complex changes in the social behaviors and activities of bumblebees – a very bad thing for creatures who rely on their colonies to survive. Bumblebees exposed to imidacloprid became less social and spent less time together. The bees also spent less time nursing larvae, foraging and constructing the wax canopy which insulates and regulates the temperature of the hive.

Neonicotinoid Residues in Nectar and Foliage of Systemically Treated Woody Landscape Plants

We measured uptake and dissipation of soil-applied imidacloprid and dinotefuran in nectar and leaves of 2 woody plant species, a broadleaf evergreen tree (Ilex attenuata) and a deciduous shrub (Clethra alnifolia), to assess concentrations to which pollinators and pests might be exposed in landscape settings. Three application timings, autumn (postbloom), spring (prebloom), and summer (early postbloom), were evaluated to see if taking advantage of differences in the neonicotinoids’ systemic mobility and persistence might enable pest control while minimizing transference into nectar.

Glyfosaat blijkt indirect bij te dragen aan de sterfte onder bijen

Dat hebben onderzoekers van de universiteit van Texas (Austin) ontdekt. Ze stelden honingbijen bloot aan glyfosaat, het actieve bestanddeel van Roundup. Drie dagen later reeds bleken de bijen behoorlijk wat goede bacteriën in hun darmen kwijt te zijn geraakt. Met name de bacterie Snodgrassella alvi werd hard geraakt. Deze bacterie is heel belangrijk voor de bijen, omdat deze ze helpt om voedsel te verwerken en zich tegen ziekteverwekkers te beschermen.

Bee losses in Virginia over the winter nearly 60 percent

Winter losses of honeybee colonies over the 2017-2018 season were greater than expected and greater than the average of 30 percent per year for the past decade. “The winter losses were 59.5 percent,” said Keith Tignor, Virginia State Apiarist. He adds that this is the highest rate since 2000 when the state began monitoring winter losses. There was a decrease in colony losses reported for the summer of 2017 when compared to the 2016 summer season. VDACS staff found high levels of Varroa mites and nosema infections in wintering bees.

The importance of time-to-effect experiments rather than fixed-duration studies for evaluating chronic toxicity

Synthetic fungicides are pesticides widely used in agriculture to control phytopathogenic fungi. The systemicity, persistency and intense application of some of these fungicides, such as boscalid, leads to long periods of exposure for honeybees via contaminated water, pollen and nectar. We exposed adult honeybees in the lab to food contaminated with boscalid for 33 days instead of the standard 10-day test. Most of the toxic effects were observed after 10 days.