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
