On June 20th I posted about a spray trial I had applied that day with 4 different materials for control of scale. Meghan Baker helped me collect samples from that study on July 27 and I looked at the results.
The following numbers are the percentage of dead scales based on observing at least 100 scales:
Check -- 53% dead
Movento + Liberate -- 69% dead
Lorsban -- 75% dead
Safari -- 83% dead
Dimethoate + Asana -- 84% dead.
Remember that these were applied with a backpack mistblower which never does give as good results as with a high pressure sprayer. Hopefully with a bit more forceful coverage you would be getting closer to 95% control with the Dimethoate +Asana.
The Lorsban results were a bit disappointing. I was hoping control would be better. Safari worked well. I've seen situations when it hasn't worked as well, but there has been plenty of rainfall in that area which probably helped it get in the plant better.
I will re-evaluate control in these trees in the fall to see if any clearer differences emerge. I will also apply these same materials to other trees in September to look further at fall scale control as well as twig aphid control the following spring.