Insecticides

This letter is in response to Julee Boan’s excellent article about Ontario’s Endangered Species Act (Paying the Interest, Ignoring the Debt — CJ, Nov. 29). This act is extremely important and we ignore it at our peril. In towns and cities we have animal humane societies that ensure that the animals under our care in our homes are given the best protection we can offer. The animals, fish and insects in our wilderness are no less deserving. The act should be their voice to protect them from the harmful impacts of mining, fossil-fuel extraction, forestry, fishing and farming, not for the protection of these same industries. These impacts are real and can be devastating. Two examples from farming have come to my attention lately. Both were preventable.

Increasing and widespread use of neonicotinoid insecticides all over the world, together with their environmental persistence mean that surface and ground waters need to be monitored regularly for their residues. However, current multi-residue analytical methods for waters are inadequate for trace residue analysis of these compounds, while passive sampling devices are unavailable. A new method using Ultra-Performance Liquid Chromatography provided good separation of the five most common neonicotinoid compounds, with limits of quantitation in the range 0.6–1.0 ng. The method was tested in a survey of rivers around Sydney (Australia), where 93% of samples contained two or more neonicotinoids in the range 0.06–4.5 lg L1. Styrenedivinylbenzene-reverse phase sulfonated Empore™ disks were selected as the best matrix for use in passive samplers. Uptake of clothianidin, imidacloprid and thiacloprid in a flowthrough laboratory system for 3 weeks was linear and proportional to their water concentrations over the range 1–10 lg L1. Sampling rates of 8–15 mL d1 were correlated to the hydrophobicity of the individual compounds. The passive samplers and analytical methods presented here can detect trace concentrations of neonicotinoids in water.

Three of the 15 bumble bee species found in Vermont are thought to be extinct and at least one other species is in decline. Bumble bees pollinate crops such as apples, blueberries and tomatoes, making them critical to Vermont’s agricultural economy. Sara Zahendra, a field biologist with the Vermont Center for Ecostudies, says losing native bumble bees is cause for serious concern. “There’s a lot that’s bad about losing native bumble bees,” she said. “One of the main things is that they are far and away the best pollinators of tomatoes. Where there aren’t a lot of native bumble bees, people have to hand-pollinate, which is incredibly expensive.” Native bumble bees are more important than honeybees for crop pollination. Leif Richardson, an entomologist at Dartmouth College, said in a VCE news release that “Wild bees perform the majority of all pollination on Vermont farms, whether or not the managed honeybee is present.” “As an ecosystem service, pollination is worth millions annually,” Richardson continued. “But we don’t know how the loss of native bee species will affect our food supply or overall environmental health.”

Le moratoire annoncé par le commissaire européen Borg du printemps dernier ciblait trois famille de néonicotinoïde, permettant d'exclure notamment l'insecticide de marque "Cruiser" pour la protection des maïs et colza. Les abeilles devaient être "tranquilles" pour deux ans. Or, comme la décision de la Commission ne porte que sur trois familles de néonicotinoïde, le groupe Bayer a trouvé la parade en commercialisant massivement l'insecticide "Sonido" – contenant la molécule thiaclopride – dont la commission environnement au Parlement européen dans un avis de 2011 sur la santé des abeilles qui avait alerté sur les dangers de cette molécule pour les abeilles. Des estimations évaluent à 800.000 hectares en France de cultures traitées en 2014 avec ce produit, menaçant gravement les abeilles et donc l'ensemble de l'écosystème.

Parasites and pesticides are among the suspected principle drivers of pollinator declines. However, especially in the case of key wild pollinators, there is insufficient data on the relative impact of these individual environmental stressors and if they interact to increase detrimental effects. Using a fully crossed factorial design, we investigated how laboratory exposure to neonicotinoid insecticides, thiamethoxam and clothianidin, over a 9-week period and a prevalent trypanosome gut parasite Crithidia bombi affects various crucial colony traits of the bumblebee Bombus terrestris. We show that chronic dietary exposure from an early stage of colony development to doses of thiamethoxam and clothianidin that could be encountered in the field truncated worker production, reduced worker longevity, and decreased overall colony reproductive success. Further, we demonstrate a significant interaction between neonicotinoid exposure and parasite infection on mother queen survival. The fate of the mother queen is intrinsically linked to colony success, and under combined pressure of parasite infection and neonicotinoid exposure mother queen survival was lowest. This indicates increased detrimental effects of combined exposure on this crucial colony trait. Combined effects may be exacerbated in stressful natural environments where more pronounced parasite virulence is expected. Our findings reiterate that dietary exposure to neonicotinoids can impact on bumblebee colony performance and fitness. The indication of combined negative effects of ecologically relevant pressures suggests additional adverse consequences for long-term population dynamics under complex field conditions.

Dressing seeds with pesticides to control pests is a widespread practice. Recent incidents of bee losses have directed attention to the emission of abraded pesticide-coated seed particles to the environment during sowing. This phenomenon of drift of pesticide dust can lead to pesticide contamination of air, water and other natural resources in crop-growing areas. This review article presents the state of the art of the phenomenon of dust emission and drift from pesticide seed dressing during sowing and its consequences. Firstly, pesticide seed treatment is defined and its pros and cons are set out, with the focus on dust, dust emission and dust drift from pesticide-coated seed. The factors affecting emission of pesticide dust (e.g. seed treatment quality, seed drilling technology and environmental conditions) are considered, along with its possible effects. The measuring techniques and protocols and models currently in use for calculating the behaviour of dust are reviewed, together with their features and limitations. Finally, possible mitigation measures are discussed, such as improving the seed quality and the use of modified seed drilling technology, and an overview of regulations and stewardship activities is given.

Uncovering SNP (single nucleotide polymorphisms)-environment interactions can generate new hypotheses about the function of poorly characterized genetic variants and environmental factors, like pesticides. We evaluated SNP-environment interactions between 30 confirmed prostate cancer susceptibility loci and 45 pesticides and prostate cancer risk in 776 cases and 1,444 controls in the Agricultural Health Study. We used unconditional logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Multiplicative SNP-pesticide interactions were calculated using a likelihood ratio test. After correction for multiple tests using the False Discovery Rate method, two interactions remained noteworthy. Among men carrying two T alleles at rs2710647 in EH domain binding protein 1 (EHBP1) SNP, the risk of prostate cancer in those with high malathion use was 3.43 times those with no use (95% CI: 1.44–8.15) (P-interaction = 0.003). Among men carrying two A alleles at rs7679673 in TET2, the risk of prostate cancer associated with high aldrin use was 3.67 times those with no use (95% CI: 1.43, 9.41) (P-interaction = 0.006). In contrast, associations were null for other genotypes. Although additional studies are needed and the exact mechanisms are unknown, this study suggests known genetic susceptibility loci may modify the risk between pesticide use and prostate cancer.