Insecticides

Pesticide contamination and agricultural intensification threaten 24 percent of Europe’s bumblebees, according to research conducted by the International Union for Conservation of Nature (IUCN) and funded by the European Commission. The study is part an ongoing project called European Red List of pollinators, with contribution from experts of the “Status and Trends of European Pollinators” (STEP) project, which assesses the conservation status of all bees —approximately 2000 species— occurring throughout Europe. The study concludes that almost half of the 68 species in the European Union (EU) are in decline, including those at risk of extinction. Of these, a total of 16 species are listed as at risk according to the IUCN’s Red List of Threatened Species, which represents the world most trusted authority on the conservation status of species. In comparison, only 13 percent of bumblebee populations are increasing. “We are very concerned with these findings. Such a high proportion of threatened bumblebees can have serious implications for our food production,” says Ana Nieto, European Biodiversity Officer of IUCN and coordinator of the study. “Protecting bumblebee species and habitats, restoring degraded ecosystems and promoting biodiversity-friendly agricultural practices will be essential to reverse the negative trends in European bumblebee populations.”

During the neurodevelopmental period, the brain is potentially more susceptible to environmental exposure to pollutants. The aim was to determine if neonatal exposure to permethrin (PERM) pesticide, at a low dosage that does not produce signs of obvious abnormalities, could represent a risk for the onset of diseases later in the life.

Neonicotinoids currently dominate the insecticide market as seed treatments on Canada's major Prairie crops (e.g., canola). The potential impact to ecologically significant wetlands in this dominantly agro-environment has largely been overlooked while the distribution of use, incidence and level of contamination remains unreported. We modelled the spatial distribution of neonicotinoid use across the three Prairie Provinces in combination with temporal assessments of water and sediment concentrations in wetlands to measure four active ingredients (clothianidin, thiamethoxam, imidacloprid and acetamiprid). From 2009 to 2012, neonicotinoid use was increasing; by 2012, applications covered an estimated ~11 million hectares (44% of Prairie cropland) with >216,000 kg of active ingredients. Thiamethoxam, followed by clothianidin, were the dominant seed treatments by mass and area. Areas of high neonicotinoid use were identified as high density canola or soybean production. Water sampled four times from 136 wetlands (spring, summer, fall 2012 and spring 2013) across four rural municipalities in Saskatchewan similarly revealed clothianidin and thiamethoxam in the majority of samples.

On March 18, a majority of Dutch parliament rallied behind a motion of the Animal Welfare Party for a national ban on the use of all neonicotinoid insecticides in agriculture and retail sales. The Party for Animal Welfare has been campaigning for many years against the neonicotinoids. In early 2013 a parliamentary majority endorsed a motion of Esther Ouwehand for a European ban on the pesticides. Due to this motion the use of three types of neonicotinoids: imidacloprid, clothianidin and thiamethoxam is now restricted in all 27 countries of the EU. However, the European ban on neonicotinoids only applies to selected crops which are attractive to bees like sunflowers, canola and maize; this means that as much as 80 % of crops which are treated with neonicotinoids in the Netherlands remain unaffected by the EU ban. Dutch Parliament now forced Secretary of State Dijksma to take further action. A majority of political parties: PvdA , SP, GL , D66 , 50 + and Freedom Party, endorsed a ban on ALL neonicotinoids in the Netherlands for all uses in agriculture, domestic gardens and landscape uses. The motion which was passed also demanded a complete ban on a related systemic pesticide, fipronil.

Pesticides have a direct impact on the physiology and behaviour of earthworms, a Danish/French research team reports after having studied earthworms that were exposed to pesticides over generations. "We see that the worms have developed methods to detoxify themselves, so that they can live in soil sprayed with fungicide. They spend a lot of energy on detoxifying, and that comes with a cost: The worms do not reach the same size as other worms, and we see that there are fewer of them in sprayed soil. An explanation could be that they are less successful at reproducing, because they spend their energy on ridding themselves of the pesticide", the researchers, Ph. D. student Nicolas Givaudan and associate professor, Claudia Wiegand, say.

Recent research in Europe and North American has shown that very low concentrations of neonicotinoid insecticides, in some cases even less than 50 parts per billion, can affect the foraging behavior of bees and the health of colonies. Neonicotinoids are a group of insecticides with a chemical structure similar to nicotine. The active ingredients of neonicotinoid products used in greenhouses include imidacloprid, acetamiprid, dinotefuran and thiamethoxam. One reason that neonicotinoid products have been favored is because they are absorbed by plant roots and circulate in the plant.

Microbial pathogens are thought to have a profound impact on insect populations. Honey bees are suffering from elevated colony losses in the northern hemisphere possibly because of a variety of emergent microbial pathogens, with which pesticides may interact to exacerbate their impacts. To reveal such potential interactions, we administered at sublethal and field realistic doses one neonicotinoid pesticide (thiacloprid) and two common microbial pathogens, the invasive microsporidian Nosema ceranae and black queen cell virus (BQCV), individually to larval and adult honey bees in the laboratory. Through fully crossed experiments in which treatments were administered singly or in combination, we found an additive interaction between BQCV and thiacloprid on host larval survival likely because the pesticide significantly elevated viral loads. In adult bees, two synergistic interactions increased individual mortality: between N. ceranae and BQCV, and between N. ceranae and thiacloprid. The combination of two pathogens had a more profound effect on elevating adult mortality than N. ceranae plus thiacloprid. Common microbial pathogens appear to be major threats to honey bees, while sublethal doses of pesticide may enhance their deleterious effects on honey bee larvae and adults.

Pflanzenschutzmittel verschlechtern Forschern zufolge die Orientierungsfähigkeit von Honigbienen und anderen bestäubenden Insekten. Schon kleine Mengen von Pestiziden wirkten sich negativ auf das Nervensystem auch von Wildbienen und Hummeln aus, fand ein Team um den Neurobiologen Randolf Menzel von der FU Berlin heraus. Die Ergebnisse wurden aktuell im Journal "PLOS ONE" veröffentlicht. "Der Befund unserer Untersuchung ist deshalb von allgemeiner Bedeutung, weil der Einsatz von Pflanzenschutzmitteln, den sogenannten Neonicotinoiden, die das Nervensystem der Insekten beeinträchtigen und sie dadurch töten, kontrovers und heftig diskutiert wird", betonte Menzel.