Numerous surveys reveal high levels of pesticide residue contamination in honey bee comb. We conducted studies to examine possible direct and indirect effects of pesticide exposure from contaminated brood comb on developing worker bees and adult worker lifespan.
A first field study was conducted to investigate the possible adverse effects that seeds dressed with neonicotinoid insecticides pose to honeybees during sowing. It was observed that in the exposure hives bee mortality increased on the day of sowing and that the number of foraging bees decreased the days after the sowing. The corn sowing posed a significant threat to honeybees, with thiamethoxam being the most probable toxic agent. A theoretical contact exposure was calculated for a bee when flying over the sown fields, revealing a dose of 9.2 ng bee−1 close to the contact LD50 of thiamethoxam.
In late April and early May 2008 a bee mortality occurred in parts of South-West Germany, which affected approximately 12,000 colonies of bees, some of them substantially. Immediately after this became known, an intensive search for the causes of these incidences was started. Very soon, maize seeds which had been treated with the insecticidal substance clothianidin were suspected as a possible cause. Only two weeks later a clothianidin poisoning was confirmed.
During last years several cases of bee losses have been reported during the period of corn sowing in different European countries. In Italy an institutional system for bee losses survey does not exist and therefore some Italian regions decided to organise an official network to collect data and analyse dead bee samples.
Das Bienensterben war ein aktuelles Thema in der Jahreshauptversammlung des Kreisimkervereins Altkreis Gelnhausen am Wochenende in Roßbach. Im Schnitt 40 Prozent der Bienenpopulation der Imkervereine im Altkreis wurden dahingerafft.
"Eindeutig widersprechen wir der Fördergemeinschaft für nachhaltige Landwirtschaft (FNL), die allein der Bienenmilbe Varroa die Schuld an den Völkerverlusten gibt", unterstreicht NABU-Präsident Olaf Tschimpke. Das weltweite Bienensterben habe komplexe Ursachen, wie eine neue Studie der UN-Umweltorganisation UNEP belegt: Demnach schwächen der Verlust der Biodiversität, ausgeräumte Agrarlandschaften und der Einsatz von Pestiziden die Bestäuber ganz erheblich, und zwar sowohl Wildbienen und Hummeln als auch Honigbienen. "Statt auf seriöse Fakten zu bauen, missbraucht die industrienahe FNL das Deutsche Bienenmonitoring (DEBIMO) für ihre tendenziösen Botschaften", kritisiert Tschimpke.
Das Bienensterben im Kanton Bern geht weiter. Edmund Nigg, Präsident des Verbandes bernischer Bienenzüchtervereine, rechnet mit einem Verlust von 30 Prozent der 25 000 Völker.
In 2009 35 beekeeping operations from 6 federal provinces of Austria reported incidents of suspected bee poisoning to the Institute for Apiculture of the Austrian Agency for Health and Food Safety (AGES). For 33 of these operations beekeepers expressed the suspicion of an bee poisoning incident. The appearance of honey bees with symptoms of poisoning coincided to a high degree with the corn sowing period.
Im Kreis Neuburg-Schrobenhausen ist der Bestand der organisierten Imker auf 1900 Völker geschrumpft. Etliche Imker verloren in den Wintermonaten ihre Völker mit hunderttausenden Bienen.
From an anonymous (but reliable) source:"We are experiencing dwindling hives which seem to take a very long time to get back up in strength, after being on gaucho sprayed canola.