Datura stramonium L. in soybean in Austria: risk areas, extent of late-season infestation, and management implications

Datura stramonium is a serious weed in soybeans and a source of toxic tropane alkaloids. Late-season weed escapes can contaminate the crops during harvesting. The spatiotemporal spread patterns of D. stramonium in Austria and its significance for soybean cultivation based on an exhaustive distribution dataset were analyzed. Drone images and an automatic image recognition method were used to study late-season infestation in soybean fields (n = 159) in eastern Austria. The results show that this species has spread in fields in Austria, particularly in the lowlands where the largest soybean cultivation areas are located. D. stramonium puts approximately 22% of the soybean cultivation area at risk. The maps derived from the drone images revealed that late-season infestation by D. stramonium varied considerably between the soybean fields (detections per ha: 316.2 ± 957.1), with areas close to the field border being at a higher risk of infestation than areas in the field core. The preceding crop and crop sequence diversity appeared to be important drivers of the extent of infestation. The results provide an opportunity to raise awareness of D. stramonium among farmers, regulatory bodies, and food and feed producers. Recommended management options include treatment of field edges and adapted crop rotation.