Insecticides

Biographer Linda Lear says the outspoken environmentalist Rachel Carson was heroic partly for what she didn't talk about

A year and a half ago, with symposia and reverential speeches, the United States and much of the world marked the 50th anniversary of Rachel Carson's book "Silent Spring" and her courageous warnings about environmental threats. Monday -- the 50th anniversary of Carson's death -- is an opportune time to admire her equally courageous silence about matters that could have blunted the book's impact. Most people are surprised to learn that Carson lived only about 18 months after the publication of "Silent Spring." On April 14, 1964, a month shy of her 57th birthday, Carson died in the Maryland suburb of Silver Spring of complications of metastasizing breast cancer. Sadly, she had become a polarizing figure in an increasingly vituperative political atmosphere. Carson did not live to see the positive impact of her message -- prohibition of the agrichemicals aldrin, dieldrin and heptachlor; passage of the National Environmental Policy Act; establishment of the U.S. Environmental Protection Agency; the banning of DDT in the United States in 1972 and the end of its use by much of the world's agriculture within the half-century.

Heute lebt die Grauammer in Nordrhein-Westfalen fast nur noch in der Zülpicher Börde

Die Bestände vieler bekannter Feldvogelarten wie Rebhuhn, Feldlerche, Feldsperling, Kiebitz und Grauammer sind in Nordrhein-Westfalen stark zurückgegangen und zum Teil in ihrer Existenz bedroht. Heute lebt die Grauammer in Nordrhein-Westfalen fast nur noch in der Zülpicher Börde. Um das Aussterben dieses Ackervogels zu verhindern, führen die Biologischen Stationen der Region ein Projekt durch. Ziel des dreijährigen Projektes ist es, den Lebensraum der Grauammer in der modernen Agrarlandschaft zu verbessern. Die gewonnenen Erkenntnisse fließen in den Schutz der Feldvögel ein. Die Bereitschaft der Landwirte, die vorgeschlagenen Maßnahmen in der Region umzusetzen, hat in den letzten Jahren zugenommen.

Diversity of Insect Nicotinic Acetylcholine Receptor Subunits

Nicotinic acetylcholine receptors (nAChRs) are ligand‑gated ion channels that mediate fast synaptic transmission in the insect nervous system and are targets of a major group of insecticides, the neonicotinoids. They consist of five subunits arranged around a central ion channel. Since the subunit composition determines the functional and pharmacological properties of the receptor the presence of nAChR families comprising several subunit‑encoding genes provides a molecular basis for broad functional diversity. Analyses of genome sequences have shown that nAChR gene families remain compact in diverse insect species, when compared to their nematode and vertebrate counterparts. Thus, the fruit fly (Drosophila melanogaster), malaria mosquito (Anopheles gambiae), honey bee (Apis mellifera), silk worm (Bombyx mori) and the red flour beetle (Tribolium castaneum) possess 10‑12 nAChR genes while human and the nematode Caenorhabditis elegans have 16 and 29 respectively. Although insect nAChR gene families are amongst the smallest known, receptor diversity can be considerably increased by the posttranscriptional processes alternative splicing and mRNA A‑to‑I editing which can potentially generate protein products which far outnumber the nAChR genes. These two processes can also generate species‑specific subunit isoforms. In addition, each insect possesses at least one highly divergent nAChR subunit which may perform species‑specific functions.

Dr Reese Halter: What kind of a world are we leaving for our children?

Since 2009 I've been writing about the plight of beleaguered honeybees due to toxic chemicals; over five billion pounds of insecticides -- one third of them are lethal neonicotinoids (neonics) thrust into our biosphere each year. Neonics are a neuro-active insecticide fashioned after nicotine, neonics poison nerves and prevent acetylcholine from enabling neurons to communicate with each other. Over 10 million commercial beehives have died since 2008 -- this is an epic worldwide problem. My colleague Dr Henk Tennekes reported the deadly effects of neonics on both soil organisms and their 'knock-on-effects' causing starvation to meadow birds and their predators Goshawks as well as contaminating waterways for many years thereafter across Western Europe. It seems that his thorough research was blatantly disregarded elsewhere around the globe by feckless government regulatory bodies. An intrepid Dr Christy Morrissey of the University of Saskatchewan set out to investigate just how wide spread the effects of neonics were across the prairies of Western Canada. Eighty to 90 percent of the wetlands she studied were contaminated with these odious poisons, which remain in toxic concentrations within the waterways for years. She too found 'knock-on-effects' in soils extending up the food chain, which reduced populations of many animals. Earthlings are knowingly annihilating the exquisite tapestry of life or Earth's biodiversity. The strength of an ecosystem depends upon the diversity of species. By killing biodiversity, we are killing ourselves; and it's happening very quickly, globally. Dr Morrissey asked some poignant questions about the food we currently produce on our globe: "Is that the cost, no birds? Or having no butterflies? Or having no bees?"

Two cases of acute poisoning with acetamiprid in humans

Acetamiprid is a potent and a relatively new neonicotinoid insecticide. Animal studies have indicated that it has a low toxicity to mammals. Despite wide usage, human exposure resulting in toxicity is quite limited, and this is the first report in the English literature about acute acetamiprid poisoning in humans. Case Details. We herein describe two cases of acute poisoning with an insecticide formulation containing acetamiprid for suicidal purposes. Both cases experienced severe nausea and vomiting, muscle weakness, hypothermia, convulsions, and clinical manifestations including tachycardia, hypotension, electrocardiogram changes, hypoxia, and thirst in the case with the higher serum concentration of acetamiprid. The symptoms were partially similar to acute organophosphate intoxication. Supportive treatments for a variety of symptoms were sufficient for recovery, and both individuals were discharged without any complications 2 days after ingestion.

Pesticide Residues and Bees – A Risk Assessment

Bees are essential pollinators of many plants in natural ecosystems and agricultural crops alike. In recent years the decline and disappearance of bee species in the wild and the collapse of honey bee colonies have concerned ecologists and apiculturalists, who search for causes and solutions to this problem. Whilst biological factors such as viral diseases, mite and parasite infections are undoubtedly involved, it is also evident that pesticides applied to agricultural crops have a negative impact on bees. Most risk assessments have focused on direct acute exposure of bees to agrochemicals from spray drift. However, the large number of pesticide residues found in pollen and honey demand a thorough evaluation of all residual compounds so as to identify those of highest risk to bees. Using data from recent residue surveys and toxicity of pesticides to honey and bumble bees, a comprehensive evaluation of risks under current exposure conditions is presented here. Standard risk assessments are complemented with new approaches that take into account time-cumulative effects over time, especially with dietary exposures. Whilst overall risks appear to be low, our analysis indicates that residues of pyrethroid and neonicotinoid insecticides pose the highest risk by contact exposure of bees with contaminated pollen. However, the synergism of ergosterol inhibiting fungicides with those two classes of insecticides results in much higher risks in spite of the low prevalence of their combined residues. Risks by ingestion of contaminated pollen and honey are of some concern for systemic insecticides, particularly imidacloprid and thiamethoxam, chlorpyrifos and the mixtures of cyhalothrin and ergosterol inhibiting fungicides. More attention should be paid to specific residue mixtures that may result in synergistic toxicity to bees.

Neonicotinoid insecticide exposures reported to six poison centers in Texas

Neonicotinoids are a relatively newer class of insecticide. Used primarily in agriculture, neonicotinoids are also used for flea control in domestic animals. Information on human exposures to neonicotinoids is limited. Neonicotinoid exposures reported to Texas poison centers during 2000–2012 were identified and the distribution by selected factors examined. Of 1,142 total exposures, most products contained imidacloprid (77%) or dinotefuran (17%). The exposures were seasonal with half reported during May–August. The most common routes of exposure were ingestion (51%), dermal (44%), and ocular (11%). The distribution by patient age was 5 years or less (28%), 6–19 years (9%), 20 years or more (61%), and unknown (2%); and 64% of the patients were female. Of all, 97% of the exposures were unintentional and 97% occurred at the patient’s own residence. The management site was on-site (92%), already at/en route to a health care facility (6%), and referred to a health care facility (2%). The medical outcomes included no effect (22%), minor effect (11%), moderate effect (1%), not followed judged nontoxic (14%), not followed minimal effects (46%), unable to follow potentially toxic (1%), and unrelated effect (4%). The most commonly reported adverse clinical effects were ocular irritation (6%), dermal irritation (5%), nausea (3%), vomiting (2%), oral irritation (2%), erythema (2%), and red eye (2%). The most frequently reported treatments were dilution/wash (85%) and food (6%). In summary, these data suggest that the majority of neonicotinoid exposures reported to the poison centers may be managed outside of health care facilities with few clinical effects expected

Poor food quality increased the sensitivity of nontarget species to pesticide exposure, potentially leading to an underestimation of adverse effects on aquatic communities in the field

Aquatic ecosystems are characterized by fluctuating conditions that have direct effects on aquatic communities but also indirect influences such as changing the toxicity of chemicals. Because the effect of food quality on pesticide toxicity has rarely been studied, in the present study Daphnia magna juveniles supplied with 4 different food quality levels were exposed to a range of imidacloprid concentrations for 21 d. Food quality was expressed as carbon:phosphorus ratios of algae Pseudokirchneriella subcapitata (C:P 35, C:P 240, C:P 400, and C:P 1300). Survival, growth rates, and reproduction of D. magna were monitored, and the combined effects of imidacloprid exposure and the phosphorus content of algae were analyzed. A stronger effect on survival was observed at the P-deficient diet (C:P 1300), confirmed by lower 10% effect concentration (EC10) values at days 7, 9, 15, and 21 compared with diets with higher phosphorus contents. Similarly, the growth rate was reduced when D. magna were supplied with algae of low phosphorus content at imidacloprid exposure conditions. The highest reproductive output was observed for D. magna fed the optimal phosphorus diet (C:P 240), both at control and exposed conditions. Poor food quality increased the sensitivity of nontarget species to pesticide exposure, potentially leading to an underestimation of adverse effects on aquatic communities in the field.

De trend naar grootschalige en intensieve landbouw lijkt de voornaamste doodsteek te worden voor bijen

Deze week raakte bekend dat één op de drie Belgische honingbijen de winter niet overleeft, een cijfer dat dubbel zo hoog is als het Europese gemiddelde. “Nochtans delen landbouwers en bijen een lange geschiedenis: sinds oudsher maken boeren dankbaar gebruik van bestuivende bijen voor de productie”, zegt Annelore Nys (Natuurpunt). “Het Europees Landbouwbeleid moet zijn subsidies inzetten op natuur- en dus bijvriendelijke landbouwmodellen.” Het tijdelijk Europees verbod op neonicotinoïden, de nieuwe generatie pesticiden, is volgens Natuurpunt maar een eerste stap in het aanpakken van een gelaagd probleem. De vereniging wijst naar het Europees Landbouwbeleid, de grootste budgetpost van Europa, dat blijft inzetten op een verhaal waarvan vooral de grootschalige en intensieve landbouwbedrijven beter worden. “Elk jaar vloeit er bijna 400 miljoen euro aan subsidies naar de Vlaamse landbouwsector, in ruil voor die publieke middelen verwacht de samenleving publieke diensten. Terwijl het redden van de bijenpopulatie een absolute prioriteit zou moeten zijn in het landbouwbeleid, dreigt het net de doodsteek te worden voor onze bijenpopulatie. De recente hervorming van het landbouwbeleid beloofde een ambitieuze vergroening, maar leverde vooral ‘business as usual’. Het initiële voorstel bevatte een veelbelovende piste: elke landbouwer die subsidies wil ontvangen, moet een deel van het akkerland inrichten in functie van natuur. Maar doorheen de onderhandelingen werden een hele rits van uitzonderingsmodaliteiten ingebouwd zodat er op het terrein nauwelijks iets zal veranderen.

Wageningen UR gaat op zoek naar nieuwe technieken voor het verwijderen van gewasbeschermingsmiddelen uit glastuinbouwspuiwater

Deze technieken kunnen namelijk opgenomen worden in het onderzoek dat Wageningen UR Glastuinbouw doet. Ook in 2014 staan een aantal vervolgonderzoeken op de planning wat betreft de toepassing van zuiveringstechnieken om gewasbeschermingsmiddelen uit glastuinbouw spuiwater te verwijderen. Ook wordt er weer gekeken naar nieuwe technieken. De overheid heeft het voornemen om zuiveringstechnieken vanaf 2016 verplicht te stellen. Wageningen UR Glastuinbouw onderzoekt binnen het project Glastuinbouw Waterproof potentieel geschikte technieken op effectiviteit van verwijdering van gewasbeschermingsmiddelen, toepasbaarheid in een glastuinbouw situatie en kosten. De technieken die in 2012 in een eerste indicatieve proef effectief bleken te zijn, zijn in 2013 aan een nader onderzoek onderworpen. Daarnaast zijn een aantal nieuwe technieken uit de afvalwaterzuivering en de drinkwaterproductie onderzocht. Dit zijn een aantal combinaties van ozon, waterstofperoxide en UV, met verschillende behandelwijzen. Het blijkt dat hier een aantal perspectiefvolle technieken tussen zitten.