I was surprised to see how simple the formulation is on Marrone Bio Innovations Regalia as a biostimulant and for IPM. It is typically used at 30-60ml/gallon. Woah, that’s crazy. That’s worthy of a DIY formulation.
Load your soxhlet up with washed and chopped roots of Giant Knotweed (reynoutria sachalinensis) and ethanol. I believe Japanese Knotweed has the same effect, but lesser than the active ingredient in the original formulation. Run for 8 hours. Load into rotary evap and recover all solvent.
Alternately, a long soak and full evaporation will work depending on equipment and solvent needs on hand. There is potential to make a veg formula using growing plant tips as well.
It is mixed 50/50 with RO water and 12.5 grams/L citric acid is used as a stabilizer. This is a 10x concentrate, so it is used at 3-6ml/gallon foliar or drench.
Enjoy using DIY Regalia for pennies on the dollar.