Lucky, Pbo8 is Piperonyl Butoxide. It's a synergist for pyrethrins or synthetic pyrethroids. Methylated crop (seed) oil is a synergist for crop chemicals used to enhance the effectiveness of the chemical against targeted weeds. I am asking about the use of methylated crop oil as a substitute for the Pbo8 due to availability and cost. Pbo8 is approximately $25 a pint. Methylated crop oil is $25 for 2.5 gallons and is vegetable based. Methylated crop oil is applied at the rate of 1 pint to the acre so the usage between it and Pbo8 may not be much different.