General

Biologische landbouw vermindert blootstelling aan chemische stoffen, verbetert de bodem- en waterkwaliteit, en versterkt de biodiversiteit

De 'Organic Farming Research Foundation' (OFRF) in Californië heeft onlangs het 'Organic Farming for Health & Prosperity'-rapport uitgebracht. Een aantal voordelen van bio-landbouw die in het rapport benoemd worden, zijn: biologische landbouw vermindert blootstelling aan chemische stoffen, verbetert de bodem- en waterkwaliteit, versterkt de biodiversiteit en remt de klimaatverandering af. En in het rapport staat dat biologisch voedsel de wereld kan voeden.

Intoxication of soil bacteria by imidacloprid

An investigation was carried out to study the effect of imidacloprid on bacterial (Brevundimonas sp. MJ15) populations in soil. In laboratory studies test concentrations were 125, 250, 500, and 1000 ppm. Field studies involved application of imidacloprid at recommended rates and at 1.5x rate. Results from both studies revealed that imidacloprid caused significant (P<0.05) and dose-dependent reduction in bacterial soil populations. However, in the field studies recovery was seen at 28 days post-application.

The Toxic Countryside - Neonicotinoide und vergiftete Landschaft

Pestizide wurden ursprünglich als „Reaktion“ auf einen Angriff durch einen bestimmten Kultur-Schädling wie zum Beispiel Blattläusen angewendet- die vielleicht nur alle sechs Jahre aufgetreten sind. Aber systemische Pestizide werden nun „präventiv“ angewendet - auf Hunderte Millionen von Hektar als eine Art „Versicherungspolice“. Die gesamte Landschaft wird nun bewusst und permanent giftig für alle Insekten gemacht, über und unter der Erde, Jahr für Jahr. Die Toxine, die in der Kultur bis zur Ernte aktiv bleiben, überdauern dann im Boden über Jahre hinweg und werden von nachfolgenden Kulturen oder Wildblumen aufgenommen, die nun ebenfalls giftig für Bienen und Wildtiere werden. Die Behandlung von 3.000.000 Hektar Ackerland in Großbritannien mit einem tödlichen Insektizid ist jedes Jahr enorm profitabel für die beteiligten Unternehmen, aber es ist eine Katastrophe für Bienen, Schmetterlinge, Hummeln und Vögel in der Agrarlandschaft, die in dieser Beinahe-Wüste zu überleben versuchen; eine ökologische Todeszone.

The toxic landscape - is it possible to lay down such a barrage of poisons on the surface of the earth without making it unfit for all life?

In “Silent Spring”, Rachel Carson gave society a warning about the dangers of organochlorine insecticides such as DDT or dieldrin: “These sprays, dusts, and aerosols are now applied almost universally to farms, gardens, forests, and homes - non-selective chemicals that have the power to kill every insect, the "good" and the "bad", to still the song of birds and the leaping of fish in the streams, to coat the leaves with a deadly film, and to linger on in soil - all this, though the intended target may be only a few weeds or insects. Can anyone believe it is possible to lay down such a barrage of poisons on the surface of the earth without making it unfit for all life?.” The situation is not much different today. Wild pollinators and honeybees alike have been facing an increasingly toxic landscape since the introduction and rapid uptake of neonicotinoids in the late 1990s. Mining data from USDA, EPA, industry and California's pesticide use reporting system (the only one of it's kind), here's a snapshot of what bees are facing in the field:
- Over 2 million pounds of clothianidin, imidacloprid and thiamexotham (three neonicotinoids) are used in an average year.
- At least 143 million of our 442 million acres of cropland is planted with crops treated with one of three neonicotinoids: clothianidin, imidacloprid and/or thiamexotham.
- 83+ million of these acres are corn, upon which honeybees rely for core nutrition (corn is wind pollinated, it doesn't need bees for pollination, but its sheer abundance of pollen makes it a staple source of bee forage).

Imidacloprid movement in soils and impacts on soil microarthropods in southern Appalachian eastern hemlock stands

Imidacloprid is a systemic insecticide effective in controlling the exotic pest Adelges tsugae (hemlock woolly adelgid) in eastern hemlock (Tsuga canadensis) trees. Concerns over imidacloprid impacts on nontarget species have limited its application in southern Appalachian ecosystems. We quantified the movement and adsorption of imidacloprid in forest soils after soil injection in two sites at Coweeta Hydrologic Laboratory in western North Carolina. Soils differed in profile depth, total carbon and nitrogen content, and effective cation exchange capacity. We injected imidacloprid 5 cm into mineral soil, 1.5 m from infested trees, using a Kioritz soil injector. We tracked the horizontal and vertical movement of imidacloprid by collecting soil solution and soil samples at 1 m, 2 m, and at the drip line from each tree periodically for 1 yr. Soil solution was collected 20 cm below the surface and just above the saprolite, and acetonitrile-extractable imidacloprid was determined through the profile. Soil solution and extractable imidacloprid concentrations were determined by high-performance liquid chromatography. Soil solution and extractable imidacloprid concentrations were greater in the site with greater soil organic matter. Imidacloprid moved vertically and horizontally in both sites; concentrations generally declined downward in the soil profile, but preferential flow paths allowed rapid vertical movement. Horizontal movement was limited, and imidacloprid did not move to the tree drip line. We found a negative relationship between adsorbed imidacloprid concentrations and soil microarthropod populations largely in the low-organic-matter site; however, population counts were similar to other studies at Coweeta.

Bodembehandeling met neonicotinoiden breekt de voedselketen en brengt de afbraak van organisch materiaal in gevaar

De meeste bodemorganismen leven op of in de bovenste laag van de grond en werken gezamenlijk aan het recyclen van organisch materiaal (zoals bladafval en andere plantenresten, uitwerpselen, kadavers etc.). Bodemdieren zoals miljoenpoten, pissebedden en regenwormen op en in de grond verkruimelen organisch materiaal dat vervolgens weer gegeten wordt door springstaarten, schimmels en bacteriën en verder afgebroken wordt tot bouwstenen die dan weer beschikbaar zijn voor de plantengroei. Behandeling van de bodem met langzaam afbreekbare neonicotinoide insecticiden betekent dat ongewervelde dieren in de bodem zullen worden gedecimeerd waardoor de voedselketen in de bodem gebroken wordt. Uit recent onderzoek is gebleken dat neonicotinoiden veruit de giftigste insecticiden voor regenwormen zijn (bijlage). Recent is ook aangetoond dat neonicotinoiden het bacterieleven in de bodem negatief beinvloeden (bijlage). De afbraak van organische stof zal hierdoor in gevaar komen (bijlage).

Earthworms are more susceptible to neonicotinoids than to other modern synthetic insecticides

In this study, we used two different types of bioassay, a contact filter paper toxicity bioassay and a soil toxicity bioassay, to compare the acute toxicity of twenty-four insecticides belonging to six chemical categories on earthworm species, Eisenia fetida. It was concluded that irrespective of bioassay systems, earthworms were more susceptible to neonicotinoids than to other modern synthetic insecticides.

Imidacloprid tast de bodembiodiversiteit aan

Sinds juni 2010 is in Nederland het insecticide imidacloprid toegelaten voor de bestrijding van engerlingen en emelten op sportvelden en golfterreinen. Het is gemakkelijk toe te passen als strooimiddel dat daarna moet worden ingeregend. Het middel werkt systemisch, dat wil zeggen dat het zich door de gehele plant verspreidt. De werkingsduur is erg lang. Imidacloprid blijft ten minste twee jaar lang in de grond aanwezig. Voor de biocoenose van gazons, sportvelden en golfterreinen betekent dit dat vrijwel alle insecten in de bodem, die chronisch worden blootgesteld aan dit middel, zullen worden vergiftigd. Recent is ook bekend geworden dat imidacloprid een negatieve invloed heeft op het bacterieleven in de bodem (bijlage). Bovendien is imidacloprid giftig voor regenwormen. Uit recent onderzoek is gebleken dat neonicotinoiden veruit de giftigste insecticiden voor regenwormen zijn (bijlage). Afbraak van organische stof zal hierdoor in gevaar komen. Afgemaaid gras van de behandelde oppervlakken moet eigenlijk worden beschouwd als chemisch afval.

Imidacloprid has a negative impact on soil bacterial diversity and upsets soil microbial balance

The current study was conducted to evaluate the effects of imidacloprid on soil microbial diversity. The results clearly showed that imidacloprid has significant negative impact on soil bacterial diversity in highly polluted farms and soil microbial balance has been gradually upset by application of more pesticide.

Physiological and behavioural effects of imidacloprid on two ecologically relevant earthworm species

Earthworms play key roles in soils and sublethal effects of environmental toxicants on these organisms should be taken seriously, since they might have detrimental effects on higher ecological levels. Earthworms make important contributions to the breakdown of organic matter, soil fertility, and to the formation of soils. In laboratory experiments we have assessed sub-lethal effects of imidacloprid on two earthworm species commonly found in different agricultural soils (Lumbricus terrestris and Aporrectodea caliginosa). After 7 days of exposure in contaminated soil, a significant loss of body mass was found in both species exposed to imidacloprid concentrations as low as 0.66 mg kg-1 dry soil. These losses ranged from 18.3 to 39% for A. caliginosa and from 7.4 to 32.4% for L. terrestris, respectively. The detected sub-lethal effects were found close to the predicted environmental concentration (PEC) of imidacloprid, which is in the range of 0.33–0.66 mg kg-1 dry soil.