Background information on endemic damage to bees in South Germany
An unusual bee mortality has been observed in parts of South Germany since the end of April. The local authorities, the laboratory for the investigation of bee poisoning incidents at the Julius Kühn-Institute and the BVL are working hard to clarify the problem.
One possible cause being discussed at the moment is poisoning with the active substance clothianidin which is contained in some insecticides. There is evidence to show that the bees have been contaminated with this active substance through the planting of maize.
Clothianidin is an active substance which is contained in various plant protection products which are used mainly for seed treatment. One of these products, Poncho ( = Poncho Pro) has been authorised by the BVL for treating maize, amongst other crops, since 2004. The admissible dose depends on the intended use: for frit-fly and wire-worm infestation the seeds are treated with 25 g active substance per 50,000 grains; however, to protect seeds from high infestation pressure by the western corn rootworm, 62 g active substance are admissible for 50,000 grains. Up until now, bee damage of this kind in conjunction with this product has not been observed in Germany.
In the authorisation procedure for plant protection products, the possible impact of products on bees is assessed, including products which are intended for treating seeds. This includes the product Poncho, which was assessed thoroughly for hazardous effects to bees by the authorities involved in the authorisation procedure. Since the active substance clothianidin is very toxic for honeybees, a series of practical trials were performed to test the impact of seed treatment on bees. The tests showed no negative impact on mortality, colony and brood development, flight intensity, behaviour or orientation ability. Clothianidin residues in materials which are relevant for bees were clearly below critical concentrations for bees.
Preliminary investigations of bee damage in Baden-Württemberg have shown that pneumatic seeding machines can cause considerable dust drift with active substance abrasion, depending on their construction, which could possibly lead to clothianidin contamination in bees and be responsible for the bee damage.
Due to current findings and knowledge, the BVL recommends the immediate measure of removing beehives from the vicinity of areas where maize treated with clothianidin has been sown, or is intended to be sown. Operators who still intend to sow maize should preferably use equipment where discharged air is directed towards the soil. For pneumatic equipment where discharged air is directed upwards or to the sides, the exhaust duct should be fitted with a hose which allows the air to escape close to the soil.
Regardless of whether clothianidin really is responsible for the bee damage or not, the BVL will use the findings to examine dust drift from pneumatic seeding machines, and in this regard to re-assess seed treatment products containing clothianidin, and others, and if appropriate, to modify the corresponding authorisations.
Information on the active substance clothianidin
Clothianidin is a relatively new insecticidal active substance from the group of neonicotinoids and has a wide spectrum of activity. The active substance was developed especially for use as a soil insecticide for treating seeds.
Status in the EU
Clothianidin has been assessed in the EU Community procedure; in 2002 the procedure had reached the point where the Member States were allowed to grant provisional authorisations; in 2006 clothianidin was included in the positive list of active substances which are allowed to be used in plant protection products, for a period of 10 years.
Authorisations in Germany
Plant protection products containing clothianidin have been authorised in Germany since September 2004. At present, there are six authorised products containing clothianidin as the only active substance or in combination with beta-cyfluthrin. The products are used for various harmful insects in arable farming and vegetable growing. Five of the six products are used for seed treatment, one is used for potatoes either for treating the plants at setting or for spraying them later on.
Table: six authorised products containing clothianidin as the only active substance or in combination with beta-cyfluthrin.
|description||ref. no.||authorised since||active substance/s||crops||use|
|¹ partly also sold under the name “Poncho Pro”|
² sold under the name “Poncho Alpha” up until 2006
|Poncho¹||5272-00||08.09.2004||Clothianidin||maize, sweetcorn, carrots||seed treatment|
|Poncho ungefärbt||5429-00||08.09.2004||Clothianidin||fodder beet, sugar beet||seed treatment|
|fodder beet, sugar beet||seed treatment|
|fodder beet, sugar beet||seed treatment|
|Dantop||5583-00||30.05.2005||Clothianidin||potatoes||plant treatment / spraying|
EU assessment of active substance: technical test report
Publication date: 13.05.2008
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