AbstractsBiology & Animal Science

Ban of Neonicotinoid Pesticides

by Prapaporn Inthasen




Institution: Roskilde University
Department:
Year: 2014
Keywords: Neonicotinoids; Bees
Record ID: 1119244
Full text PDF: http://rudar.ruc.dk/handle/1800/13173


Abstract

European Union (EU) has banned the use of three pesticides: clothianidin, thiamethoxam and imidacloprid in bee attractive crops. These pesticides all belong to a pesticide group called neonicotinoids, and they are believed to be a contributing factor in the declining bee population. The ban was enforced in EU the 1st of December 2013. Neonicotinoids (clothianidin and thiamethoxam) are an important part of the control of pests in oilseed rape production in Danish agriculture. The neonicotinoids are generally used as a seed treatment in oilseed rape. The coatings of the rape seeds prevent young plants from pest attack. The seed treatment of oilseed rape helps controlling Cabbage stem flea beetle (Psylliodes chrysocephala). The lack of seed treatment in oilseed rape could result in extra treatments with pyrethroids (lambda-cyhalothrin, Gamma cyhalothrin and Cypermethrin). This project aims to identify if the banning of the three neonicotinoids (clothianidin, thamethoxam and imidacloprid), seems to result in a farming practice that puts more or less pressure on the Danish environment, with special emphasis on honey bees. In Denmark there has not been reported poisoning of honey bees from either pyrethroids or neonicotinoids. Pesticides are among the Danish apiculturist not seen as a major concern, which indicates little identified negative effect of the neonicotinoids on honey bees. When treatment with neonicotinoids in oilseed rape is substituted with a treatment with pyrethroids, the time of application should pose no threat to honey bees, as the crop are not flowering and the application period will be in the autumn, where few flowers are present in the Danish environment. The change in oilseed farming practice does not necessarily increase the load on the Danish environment (based on calculation of Area Load). If the Danish farmers substitute the neonicotinoids seed treatment with an extra treatment of the pyrethroid with the least Area Load (Karate WG (Lambda-cyhalothrin)). If Danish farmers based on the higher taxation, in the future solely will use Karate WG in oilseed rape, the Area Load can actually decrease compared to before the ban of neonicotinoids even with three applications. Findings of resistance in Cabbage stem flea beetle in Germany towards pyrethroids makes a plausible scenario being breakdown of control of this pest in oilseed rape. Previously the control of Cabbage stem flea beetle has been based on neonicotinoids and pyrethroids, which have different modes of action in Cabbage stem flea beetle. Resistance among Cabbage stem flea beetle towards pyrethroids would result in the need of stronger doses and more applications, which would give rise to higher load on the environment including bees (increase in AL). A worst case scenario could be the need to abandon cultivation of rape in Denmark.