English

Neonicotinoid insecticides have come under scrutiny for their potential unintended effects on non-target organisms, particularly pollinators in agro-ecosystems. As part of a larger study of neonicotinoid residues associated with maize (corn) production, 76 water samples within or around the perimeter of 18 commercial maize fields and neighbouring apiaries were collected in 5 maize-producing counties of southwestern Ontario. Residues of clothianidin (mean = 2.28, max. = 43.60 ng/mL) and thiamethoxam (mean = 1.12, max. = 16.50 ng/mL) were detected in 100 and 98.7%of the water samples tested, respectively. The concentration of total neonicotinoid residues in water within maize fields increased six-fold during the first five weeks after planting, and returned to pre-plant levels seven weeks after planting. However, concentrations in water sampled from outside the fields were similar throughout the sampling period. Soil samples from the top 5 cm of the soil profile were also collected in these fields before and immediately following planting. The mean total neonicotinoid residue was 4.02 (range 0.07 to 20.30) ng/g, for samples taken before planting, and 9.94 (range 0.53 to 38.98) ng/g, for those taken immediately after planting. Two soil samples collected from within an conservation area contained detectable (0.03 and 0.11 ng/g) concentrations of clothianidin. Of three drifted snow samples taken, the drift stratum containing the most wind-scoured soil had 0.16 and 0.20 ng/mL mainly clothianidin in the melted snow. The concentration was at the limit of detection (0.02 ng/mL) taken across the entire vertical profile. Our results suggest that neonicotinoids may move off-target by wind erosion of contaminated soil. These results are informative to risk assessment models for other non-target species in maize agro-ecosytems

Earthworms (Eisenia fetida) are one of the most abundant terrestrial species, and play an important role in maintaining the ecological function of soil. Neonicotinoids are some of the most widely used insecticides applied to crops. Studies on the effect of neonicotinoids on E. fetida are limited. In the present work, we evaluated the effects of five neonicotinoid insecticides on reproduction, cellulase activity and the tissues of E. fetida. The results showed that, the LC50 of imidacloprid, acetamiprid, nitenpyram, clothianidin and thiacloprid was 3.05, 2.69, 4.34, 0.93 and 2.68 mg kg−1, respectively. They also could seriously affect the reproduction of E. fetida, reducing the fecundity by 84.0%, 39.5%, 54.3%, 45.7% and 39.5% at the sub-lethal concentrations of 2.0, 1.5, 0.80, 2.0 and 1.5 mg kg−1, respectively. The cellulase activity of E. fetida was most sensitive to clothianidin. Significant disruption of the epidermal and midgut tissue was observed after 14 d exposure. In summary, we demonstrate that imidacloprid, acetamiprid, nitenpyram, clothianidin and thiacloprid have high toxicity to earthworm, and can significantly inhibit fecundity and cellulase activity of E. fetida, and they also damage the epidermal and midgut cells of earthworm.

Imidacloprid (IMD) is a neonicotinoid insecticide soil-drenched on sandy soils of southwest Florida for the control of Diaphorina citri Kuwayama or Asian citrus psyllid (ACP). The ACP vectors causal pathogens of a devastating citrus disease called citrus greening. Understanding the behavior of IMD in these soils and plants is critical to its performance against target pests. Samples from Immokalee fine sand (IFS) were used for sorption kinetics and equilibria experiments. IMD kinetics data were described by the one-site mass transfer (OSMT) model and reached equilibrium between 6 and 12 h. Batch equilibrium and degradation studies revealed that IMD was weakly sorbed (KOC = 163–230) and persistent, with a half-life of 1.0–2.6 years. Consequently, IMD has the potential to leach below the citrus root zone after the soil-drench applications.

The Ontario government has unveiled North America’s first agricultural restrictions on a widely used class of pesticides blamed for the decline in bees and other pollinators.The controversial regulations aimed at reducing the use of neonicotinoid insecticides made by Bayer AG and Syngenta AG by 80 per cent within two years goes into effect on July 1. The province said on Tuesday it wants to reduce the overwintering death rate of honey bees to 15 per cent from an average of 34 per cent by controlling the planting of seeds treated with the three most commonly used neonicotinoids. Glen Murray, Ontario’s Minister of the Environment, said the rules are “highly workable” and address farmers’ concerns while reducing damage from neurotoxic pesticides that are persisting in streams and soil and affecting everything from birds and bees to butterflies and aquatic life. The rules, which are intended to improve the health of insects responsible for pollinating about $900-million worth of crops, require that farmers who use neonic-treated seeds to grow corn and soybeans show they have insect problems, and that seed vendors be licensed. Vendors of other pesticides require licences, and the new Ontario rules simply add neonics to that regime, he noted. Establishing, administering and enforcing the licensing and planting system will cost $3-million to $4-million a year, said Mr. Murray, conceding there is little to prevent anyone from purchasing the treated seeds in the United States.

Scientists report that after two decades of attempts to save the species, northern spotted owl (Strix occidentalis) numbers in the Northwest are still on the decline — and at a faster rate. The threatened bird nests in old trees and is at the heart of a decades-long struggle over the fate of the region’s old-growth forests. Scientists at a conference Tuesday in Vancouver, Washington, reported that owl numbers are now dropping at an annual rate of 3.8 percent, said U.S. Forest Service spokesman Glen Sachet. Five years ago, the rate was 2.8 percent. The scientists also said population declines are more widespread in the bird’s range from Washington through Northern California.

Sea birds in Cornwall such as the puffin, fulmar, Kittiwake and Balearic shearwater have been listed as endangered and vulnerable in the new list of Euorpean birds. The EU Red List of Birds, which was published yesterday is a groundbreaking three-year study which describes the conservation status of over 500 species. At the European level it lists 13% birds as threatened, and a further 6% near threatened. Of particular concern in the West Country are a number of the region's seabirds. Topping the list is the critically endangered Balearic shearwater, a visitor to the region's coastal waters particularly in summer and autumn. With a population estimated at just 3,200 pairs globally this bird faces threats from predation by introduced mammals where it breeds, and from fishing by-catch. There are concerns too for the ever popular puffin – a bird that breeds on the Isles of Scilly, Lundy and occasionally on the mainland in the region.

In a recent issue of the journal Science, Dave Goulson and colleagues presented a review entitled “Bee declines driven by combined stress from parasites, pesticides, and lack of flowers”. This stimulated Jaboury Ghazoul to submit a letter to Science criticising the Goulson et al. paper from a number of perspectives, but particularly the paucity of the evidence base for pollinator declines. Dave and his co-authors robustly responded to that letter, as you might imagine. In some respects this was an unsatisfactory exchange, however, as the focus was largely on agricultural pollinators, rather than pollinators of all plants (including the majority non-cultivated species) and I think that (perhaps with more space?) Dave could have outlined the evidence in more depth. The most striking statement in Jaboury’s letter was that the “evidence for pollinator declines is almost entirely confined to honeybees and bumblebees in Europe and North America”. Now, even given the fact that Jaboury was possibly referring specifically to agricultural pollinators, that is a very extreme statement to make. Underlying it is the suggestion that global concerns about declining pollinator biodiversity (a subject I’ve discussed repeatedly on this blog) is underpinned by a taxonomically and geographically thin evidence base. Is that really true? I don’t believe so and I think it’s worth presenting a brief overview of the evidence, not least because Dave’s review and the resulting correspondence is pay-walled at the Science site (though if you Google the titles you might, just might, find copies posted on the web…).

Two iconic Australian shorebirds have been added to the critically endangered list. The extraordinary sickle-billed Eastern curlew, and its smaller cousin, the curlew sandpiper (Calidris ferruginea) , are the first shorebirds on the list. The Eastern curlew is the largest migratory shorebird in the world, known for using the length of its extraordinary bill to work deep down into mud and sand after prey. The curlew sandpiper was until recently one of the most common of the group of small shoreline-running birds found along Australia's coasts. At the furthest extent of the East Asian-Australasian flyway, in southern Tasmania, the most catastrophic losses have been counted. There, 90 per cent of curlews have gone and 100 per cent of curlew sandpipers, said Eric Woehler, convenor of BirdLife Tasmania. Across the country there has been an 81 per cent decline in curlews over three generations, and an 82 per cent decline in curlew sandpipers, according to official advice to the Environment Minister, Greg Hunt.

Thirty-two honeybee (Apis mellifera) colonies were studied in order to detect and measure potential in vivo effects of neonicotinoid pesticides used in cornfields (Zea mays spp) on honeybee health. Honeybee colonies were randomly split on four different agricultural cornfield areas located near Quebec City, Canada. Two locations contained cornfields treated with a seed-coated systemic neonicotinoid insecticide while the two others were organic cornfields used as control treatments. Hives were extensively monitored for their performance and health traits over a period of two years. Honeybee viruses (brood queen cell virus BQCV, deformed wing virus DWV, and Israeli acute paralysis virus IAPV) and the brain specific expression of a biomarker of host physiological stress, the Acetylcholinesterase gene AChE, were investigated using RT-qPCR. Liquid chromatography-mass spectrometry (LC-MS) was performed to detect pesticide residues in adult bees, honey, pollen, and corn flowers collected from the studied hives in each location. In addition, general hive conditions were assessed by monitoring colony weight and brood development.