Fluorescence Imaging for Investigating the Efficiency of Formulations, Adjuvants, and Application Systems Available to Purchase

Several herbicides reduce, directly or indirectly, the efficiency of photosynthesis of plants. As a consequence, the fluorescence of the chlorophyll increases. The relative increase of fluorescence [(F_m-F_o)/F_m] can be used to compare the influence of formulations and adjuvants on the activity of herbicides. This procedure allows the accurate and non-destructive screening of sprayed plants in the first minutes and hours after treatment. A new development is the automated imaging and quantification of the relative increase of fluorescence at the whole plant level. Use of a robot-arm enables a laser-camera to take pictures of the chlorophyll fluorescence of different plants with short time intervals between plants. This procedure makes it possible to screen hundreds of plants simultaneously. Individual pictures can be used, or pictures can be used to compose a video demonstrating the dynamics of the herbicide action. The potency of this technology for monitoring bentazon, glufosinate and glyphosate action is demonstrated. In addition to investigating the influence of formulations and adjuvants on herbicide activity, the fluorescence imaging technology can be used to monitor phytotoxicity of formulations and spray application parameters like water volume and drop size.