Overige insecten

Gerade erst sind die als bienenschädlich entlarvten Neonicotinoide in der EU zum Teil verboten worden. Jetzt haben Schweizer Forscher festgestellt, dass diese Insektizide entgegen bisherigen Annahmen auch für Kleinkrebse und andere Wassertiere giftig sind. Das Nervengift stört schon bei geringen Konzentrationen die Bewegung und Nahrungsaufnahme der Krebse. Hält die Pestizidbelastung länger an, verhungern sie daher. Diese Langzeitfolge wird von den gängigen Toxizitätstests nicht erfasst, weil diese nur die kurzfristigen Folgen prüfen, warnen die Forscher im Fachmagazin "PloS ONE".

Dat schrijft staatssecretaris van Economische Zaken Sharon Dijksma (PvdA) in een brief aan de Tweede Kamer. Met het verbod op het landbouwgif moet grootschalige bijensterfte worden tegengegaan. Eurocommissaris Tonio Borg voor consumentenbescherming liet eind april weten 'de komende weken' werk te maken van het inperken van de inzet van de middelen clothianidine, imidaclopride en thiamethoxam, die neonicotinoïden bevatten. De middelen worden gebruikt op gewassen die bijen aantrekken. Zodra het besluit van de Europese Commissie is vastgesteld, gaat Dijksma het in Nederland implementeren. Landen krijgen tot 1 december de tijd om het besluit in te voeren. Felle kritiek werd geuit op de weigering van Sharon Dijksma in Nederland nog sneller tot actie over te gaan. Straks na het neerdwarrelen van de laatste vergiftigde bij, is Sharon Dijksma van de PvdA ongetwijfeld de eerste die vanuit ' mijn directe verantwoordelijkheid en oprechte bezorgdheid' een brede commissie van onderzoek zal installeren die...., aldus de Trouwschrijfster.

A biologist with Bird Studies Canada in Sackville is warning people that the chimney swift (Chaetura pelagica) is disappearing in New Brunswick. Allison Manthorne, co-ordinator of Maritimes SwiftWatch, says the population of chimney swifts has declined by 95 per cent in Canada since 1968, with a close to 50 per cent range shrinkage in the Maritimes. "The chimney swift historically lived in hollow trees, the kind of tree that you find in an old growth forest and our landscape has changed so much that nesting and roosting spaces don't really exist anymore," she said. And while the birds adapted to using the chimneys of schools, churches, houses and industrial buildings, many chimneys are now being capped, steel-lined or torn down, further reducing their nesting options. Insect decline is another problem, said Manthorne. Flying insects, such as mosquitoes, are the major food source for chimney swifts, she said. Chimney swifts are small grey-brown birds with long, pointed wings and short, tapered bodies. They are often mistaken for swallows due to their shape and size. They spend the winter months in the upper Amazon basin of South America including Peru, northwestern Brazil and northern Chile and breed in New Brunswick and Nova Scotia.

Effects of two series of imidacloprid pulses on caged amphipods (Gammarus roeseli) and their shredder efficiency for litter decomposition were studied for 70 days as part of a comprehensive stream mesocosm experiment. The duration of each imidacloprid pulse of 12 µg L−1 was 12 h. About 250 mL cages with an initial stock of 10 adult gammarids together with different conditioned litter substrates were used. Beside alder leaves (Alnus glutinosa), straw (× Triticosecale) was also used in different trials and tested for its suitability to serve as litter substrate. Results from tracer and microprobe measurements approved the suitability of the test system under low-flow condition of 10 cm s−1 in the surrounding stream water. Population development followed a logistic growth function with a carrying capacity of 200 Ind cage−1 for alder and 161 for straw. In the course of the study, the F1 generation reached sexual maturity and F2 offspring appeared. Increased nitrogen contents of gammarid-free trials compared to stocked ones after 70 days indicated that biofilm on both substrates was an important food source for G. roeseli. However, increased shredding activity by gammarids was only detected for alder during the second pulse series. During the remaining time and also for straw, losses of coarse particular organic matter were quite constant and slow indicating the dominance of transport limited decomposition processes on the litter surfaces. No effect of imidacloprid pulses on population levels and litter decomposition could be detected. However, the number of brood carrying females was reduced in the treatments compared to the control groups in the last 3 weeks of the study. In conclusion, repeated low-level and short-term exposition may have adverse long-term effects on G. roeseli in the field with regard to both the population size and the functional role as key shredder.

Honeybee colony losses continue to be unacceptably high. In the US this spring, colonies brought in to California to pollinate almonds from throughout the country, about half of the colonies were lost (New York Times, March 29, 2013). It is generally accepted that multiple pathogens ultimately bring down stressed colonies (Cornman 2012). However the role of pesticide stress on colonies remains controversial. Chronic exposure studies are often poorly constructed and frequently do not follow the exposed insects long enough for effects of the toxin to become evident. The best studies look at mortality, or behavioral effects, over a substantial fraction of the insect’s lifespan while varying the toxin concentration or dose. Time-to-effect studies lend themselves to a simple time dependent “power law” empirical model which can guide expectations for field toxicity effects (Tennekes 2011, Sánchez-Bayo 2009). Other reviews of the toxicity of imidacloprid (Cresswell 2011) attempt to establish specific “acute” or “chronic” levels, but this seems useless if the time of exposure is not explicitly included. Hence, I’ve made an effort to identify relevant time-to-effect studies in the literature most specifically for imidacloprid with insects of order hymenoptera, which includes bees and ants.

Dow AgroSciences LLC, a wholly owned subsidiary of The Dow Chemical Company (NYSE: DOW), announced today that U.S. regulatory authorities have approved the new insecticidal active ingredient, sulfoxaflor to be marketed in the U.S. as Transform® and Closer™. The U.S. registration, and the recent Canadian registration, are the result of a Global Joint Review which also includes Australia. Australian sulfoxaflor registration is expected by third quarter 2013. South Korea, Panama, Vietnam, Indonesia, and Guatemala have already registered sulfoxaflor and additional global registrations are expected in the near future. Sulfoxaflor belongs to a novel chemical class called sulfoximines invented by Dow AgroSciences and offers extremely effective control of many important sap-feeding insect pests. It can be used in a large number of major crops, including cotton, soybean, citrus, pome/stone fruit, nuts, grapes, potatoes, vegetables and strawberries.

In the early 1990s Bayer scientists launched onto the world the chemical weapon from hell; a powerful neurotoxin that, as Dutch toxicologist Dr Henk Tennekes demonstrated (and others have subsequently confirmed), causes a virtually irreversible blockage of postsynaptic nicotinergic acetylcholine receptors in the central nervous system of all invertebrates from pollinators down to soil and aquatic organisms. The pesticides industry stands accused of failure to investigate the hazards of systemic neonicotinoids fully and of failure to establish standard tests and protocols. The protection agencies stand accused of failing to protect human health and the environment.

Little research has focused on the direct effects of insecticides on plants. Here we demonstrate that applications of neonicotinoid insecticides, one of the most important insecticide classes worldwide, suppress expression of important plant defense genes, alter levels of phytohormones involved in plant defense, and decrease plant resistance to unsusceptible herbivores, spider mites Tetranychus urticae (Acari: Tetranychidae), in multiple, distantly related crop plants. Using cotton (Gossypium hirsutum), corn (Zea mays) and tomato (Solanum lycopersicum) plants, we show that transcription of phenylalanine amonia lyase, coenzyme A ligase, trypsin protease inhibitor and chitinase are suppressed and concentrations of the phytohormone OPDA and salicylic acid were altered by neonicotinoid insecticides. Consequently, the population growth of spider mites increased from 30% to over 100% on neonicotinoid-treated plants in the greenhouse and by nearly 200% in the field experiment. Our findings are important because applications of neonicotinoid insecticides have been associated with outbreaks of spider mites in several unrelated plant species. More importantly, this is the first study to document insecticide-mediated disruption of plant defenses and link it to increased population growth of a non-target herbivore. This study adds to growing evidence that bioactive agrochemicals can have unanticipated ecological effects and suggests that the direct effects of insecticides on plant defenses should be considered when the ecological costs of insecticides are evaluated.

Research by Utrecht University has demonstrated a link between the insecticide imidacloprid and the abundance of insects and other invertebrates in surface-water: http://dx.plos.org/10.1371/journal.pone.0062374. The concentration of imidacloprid in surface water was in excess of the limit in almost half the sites monitored by Water Boards in the Netherlands in the past eight years. In one instance, the imidacloprid concentration in surface water was 25,000 times above the limit. On average they found three times less invertebrates in polluted locations than in water that meets the standard. The scientists found that even below the limit of 13 nanogram per litre, imidacloprid still adversely affected aquatic insect life. The data underpin Henk Tennekes' long-standing thesis that ground and surface water contamination with persistent insecticides that cause irreversible and cumulative damage to aquatic and terrestrial (non-target) insects must lead to an environmental catastrophe, as described in chapter 3 of his book "The Systemic Insecticides: A Disaster in the Making", published in November 2010 (attached).