Great answers! I didn't know that the mixture is possibly good only for a certain number of hours; that's definitely possible they use a preservative. Also my mixture was definitely not 90% canola. I didn't realize I need that much. I was afraid of suffocating the stomata. I made 2 liters of solution with 6 teaspoons of the pyrethrins, a cup of canola, a little dawn, and the rest was water, so I bet I do not have nearly enough canola in my solution. I agree that the horticultural oil is a better idea, I just had canola on hand at the time. For the person who askeed, Bonide pyretherine garden insect spray concentrate was what I used. These were all very thoughtful answers - I really didn't expect that! Thank you so much as it definitely sheds light on several possible reasons. What a great group of community members.
