Quassia, an Effective Aphid Control Agent for Organic Hop Growing

Summary in the original language of the document

In the first three decades of the 20th century, quassia extract was widely used in hop growing as a chemical agent to control Phorodon humuli and other insect pests. In the first years of the 21st century this compound was rediscovered by German organic hop growers. In several efficacy trials conducted during five field seasons, quassia pro¬ducts proved to be effective control agents for P. humuli in organically grown aroma cultivars. A systemic variant developed by painting a suspension of quassia extract to the bines was the best method of application. This method proved not only to be very effective, but was also best from an environmental point of view. The optimal systemic application rate was determined as 24 g/ha of the active ingredient quassin. In order to generate the data necessary for registration of quassin in Annex I of the EU Council Directive 91/414/EEC, further efficacy trials were conducted during 2007. The results emphasize the importance of this compound as currently the only suitable aphid control agent in organic hop growing, especially when applied systemically.