At your 10ppb concentration you could see some fanwort control. If it were my pond based the journal article I would treat again as another 10ppb or add a second treatment of 20ppb. Another option is to add a 2nd 10 ppb and watch the results. The 2nd fluridone 10ppb bump, if not a long delay from the 1st dose, may be enough accumulative effect to significantly reduce fanwort? Long delay = >2weeks and by then some of the first 10ppb will have dissipated. . Then if there is poor Fanwort control this year, next year treat real early as soon as new growth is seen with 20-25ppb. Treating very early in the growth phase works best for control of fanwort.
Report your results for all to learn.
Reference -
https://apms.org/wp-content/uploads/japm-40-02-058.pdfIn conclusion, the data from these studies showed that under these experimental conditions, the dose of fluridone required to substantially reduce fanwort growth (20 µg L-1 reduced biomass >80%), also severely impacted water marigold growth. (1ug/L = 1ppb).
