Allelopathy in the field: Artemisinin in Artemisia annua as a herbicide in various cash crops.

Allelopathy in the field: Artemisinin in Artemisia annua as a herbicide in various cash crops The allelopathic effect of artemisinin was proved in a four years trial series in the field. Artemisinin is present in the organic material of Artemisia annua. Dry leaf tissue of Artemisia annua was superficially incorporated in the soil. A significant reduction of number and dry weight of weeds was observed in some trials. To verify the allelopathic effect two different varieties “Linie A” with poor content of artemisinin and “Linie B" rich of artemisinin were tested. Neither the efficacy of the artemisinin nor the use of herbicides lead to a significant difference in yield of the crop. The reasons for this might have been a heterogeneous distribution of weeds in the fields, or varying climatic situations, or the test facilities. Artemisinin or other molecules with comparable allelopathic effects influence the flora of agricultural fields and therefore could be of practical use. In vineyards or orchards allelopathy of living mulch could be used to control weed development. In the rotation of field crops, it could be used as “cleaning” green manure to control weeds. A feasible type of application of artemisinin is still to be found. Extended knowledge of allelopathical phenomenon's can open new perspectives concerning integrated and organic production, and in systems of reduced soil tillage.