Rapid monitoring of herbicide-resistant Alopecurus myosuroides Huds. using chlorophyll fluorescence imaging technology

Sensor-based stress recognition is an effective tool for improving herbicide efficacy and selectivity. In this study, a chlorophyll fluorescence imaging sensor was used for measuring Maximal Photosystem II Quantum Yield (F v/F m) in Alopecurus myosuroides Huds. shortly after herbicide application. Five herbicides with different modes of action were sprayed on A. myosuroides field populations at three sites. Six herbicides were tested on herbicide-sensitive and herbicide-resistant A. myosuroides populations in the greenhouse. The field and greenhouse studies showed that F v/F m values of herbicide-sensitive and herbicide-resistant plants were significantly different 3 days after treatment (DAT). For the resistant populations, F v/F m values were equal to the untreated control plants. Therefore, ALS- and ACCase-inhibiting herbicides did not affect resistant populations. The PS II-inhibiting herbicide isoproturon reduced the F v/F m values of the sensitive plants faster than the resistant ones. In the greenhouse, the results were similar. A differentiation of sensitive and resistant weeds based on F v/F m values was possible already 1 DAT. We conclude that the chlorophyll fluorescence imaging sensor is capable of identifying herbicide-resistant weed populations shortly after herbicide application.