Insecticides

Nature magazine brings a chilling article on the horrendous effects of agricultural chemicals in pesticides on invertebrates and the soil. The key words: even at 'safe' levels. The results were drawn from several studies in different continents and reveal that in polluted areas, up to forty-two per cent of species were lost as a result of harmful chemicals. "Pesticides spark broad biodiversity loss", written by Sharon Oosthoek, tells a sorry tale of the effects of pesticides on biodiversity. The conclusion is that the use of pesticides has caused a sharp decline in the biodiversity of invertebrates living in streams. Studies carried out in Germany and France in Europe and in Australia showed a dramatic decline in species such as mayflies and dragonflies. Quoting he study published in the Proceedings of the National Academy of Sciences, Sharon Oosthoek went on to state some shocking details: the studies were carried out in 23 streams in Germany, 16 in France and 24 in Australia, classifying them in three categories: uncontaminated, slightly contaminated and highly contaminated. In the last category, there were up to 42% fewer species than those found in the uncontaminated group of streams in Europe, while the figure in Australia was a decrease of 27%. More seriously still, the article goes on to claim, the decrease in biodiversity occurred even at levels which scientists state to be "environmentally protective".

Honey bees are exposed to a wealth of synergistically interacting stress factors, which may induce colony losses often associated with high infection levels of pathogens. Neonicotinoid insecticides have been reported to enhance the impact of pathogens, but the underlying immune alteration is still obscure. In this study we describe the molecular mechanism through which clothianidin adversely affects the insect immune response and promotes replication of a viral pathogen in honey bees bearing covert infections. Our results shed light on a further level of regulation of the immune response in insects and have implications for bee conservation.

Bayer CropScience will introduce soon a new class of chemistry that will be an alternative to imidacloprid, the company’s embattled systemic insecticide that has been implicated in honey bee deaths. The new active ingredient is flupyradifurone. It is a systemic from the butenolide chemical class and is active on sucking insect pests. it will be registered in 2015 and marketed by Bayer under the trade name Sivanto™ as a “bee friendly” product with no bloom (application) restrictions.

To investigate effects of sublethal dietary neonicotinoid exposure on honeybee colony performance, a fully crossed experimental design was implemented using 24 colonies, including sister-queens from two different strains, and experimental in-hive pollen feeding with or without environmentally relevant concentrations of thiamethoxam and clothianidin. Honeybee colonies chronically exposed to both neonicotinoids over two brood cycles exhibited decreased performance in the short-term resulting in declining numbers of adult bees (228%) and brood (213%), as well as a reduction in honey production (229%) and pollen collections (219%), but colonies recovered in the medium-term and overwintered successfully. However, significantly decelerated growth of neonicotinoid-exposed colonies during the following spring was associated with queen failure, revealing previously undocumented long-term impacts of neonicotinoids: queen supersedure was observed for 60% of the neonicotinoid-exposed colonies within a one year period, but not for control colonies. Linked to this, neonicotinoid exposure was significantly associated with a reduced propensity to swarm during the next spring. Both short-term and long-term effects of neonicotinoids on colony performance were significantly influenced by the honeybees’ genetic background. Sublethal neonicotinoid exposure did not provoke increased winter losses. Yet, significant detrimental short and long-term impacts on colony performance and queen fate suggest that neonicotinoids may contribute to colony weakening in a complex manner.

The European Food Safety Authority (EFSA) was asked by the European Commission to perform an evaluation of imidacloprid as regards the risk to aquatic organisms. In this context the conclusions of EFSA concerning the risk assessment for aquatic organisms for the active substance imidacloprid are reported. The context of the evaluation was that required by the European Commission in accordance with Article 21 of Regulation (EC) No 1107/2009 to review the approval of active substances in light of new scientific and technical knowledge and monitoring data. The conclusions were reached on the basis of the evaluation of the representative uses of imidacloprid authorised at the time of approval of the substance. The proposed endpoints concluded as being most appropriate for use in regulatory risk assessment, derived from the submitted studies and literature data, are presented. Missing information identified as being required to allow for a complete risk assessment is listed.

Earthworms provide key soil functions that favour many positive ecosystem services. These services are important for agroecosystem sustainability but can be degraded by intensive agricultural practices such as use of pesticides. Many literature reports have investigated the effect of pesticides on earthworms. Here, we review those reports to assess the relevance of the indicators of earthworm response to pesticides, to assess their sensitivity to pesti- cides, and to highlight the remaining knowledge gaps. We focus on European earthworm species and products authorised in Europe, excluding natural compounds and metals. We consider different organisation levels: the infra-individual level (gene expression and physiology), the individual and population levels (life-history traits, population density and behaviour) and the community level: community biomass and density. Our analysis shows that earthworms are impacted by pesticides at all organisation levels. For example, pesticides disrupt enzymatic activities, increase individual mortality, decrease fecundity and growth, change individual behaviour such as feeding rate and decrease the overall community biomass and density.