Feldversuche zur Wirkung von Spinosad-, Neem- und B.t.t.- Präparaten auf die Regulierung des Kartoffelkäfers(Leptinotarsa decemlineata Say)

The Colorado potato beetle (CPB) is one of the most important pests on potatoes (Solanum tuberosum). In many areas, preventive measures are not sufficient enoughto prevent the damage caused by the CPB. Therefore insecticides such as neem and Bacillus thuringiensis v. tenebrionis (B.t.t.) have an important role in organic potato production in Germany. The new insecticide Spinosad was added to Council Regulations (EEC) No. 2092/91 on organic production in 2008. It is now possible to use Spinosad in organic agriculture in the EU. The active ingredient of Spinosad is obtained from the bacterium Saccharopolyspora spinosa through fermentation. Field studies compared three treatments to control CPB in 2008. 1: single Spinosad treatment (24 g/ha active ingredient (a.i.)) 2: first treatment B.t.t. (60 g/ha (a.i.)), second treatment (+4d) B.t.t. (100 g/ha a.i.) 3: first treatment neem (25 g/ha a.i.), second treatment (+4d) B.t.t. (100 g/ha a.i.). There was an average of 27 larvae per plant before the treatments. All treatments displayed nearly the same significant degree of effectiveness (78 % - 82 %) with regards to the damaged leaf area 25 days after treatment in comparison to the untreated control. The increment of the Spinosad treatment to untreated control was significant with more than 103 dt/ha.