The on hand survey on damage regulation through saw wesps in the ecological fruit-growing leads to the following results:
In the years 1996-1999 a significant amount of parasites was ascertained in middle Europe. Practically only trade products based on Quassia products were used for the damage regulation. With appropriate usage the reproducable effect of these preparations was proven in the observation period of time.
Indications of a reduced product quality of the Quassia formulation in the year 1999 have not been taken out of the survey results
