Dennis, Try using 'Thrip Stick' . It's a non-chemical control similar to using fly-paper. Thrip Stick is basically a piece of bright yellow plastic that has a coating of polybutene, a highly sticky substance. Thrips are attracted to the colour of the plastic and stick to it and die. I used to cut up the plastic cards into 2-3 inch squares and place these on pea sticks in pots so that they are at the same height as the flowers. The benefit of using 'Thrip Stick' is that it will also catch other flies, like fungus gnat and wasps; however it will also catch any biological control as well. They last for months but if they are successful in catching flies, can look a bit unsightly after a while. Found a good thrip link for you http://www.biocontrol.ucr.edu/WFT.html (Western Flower Thrip) Best Wishes, Dave