Are you sure the scale is not dead? They don't just fall off even if dead.

To tell, you need to scrape one off with your fingernail or something similar. If it's dead, it will be dry and just flake off easily, if it's still alive it will be squishy, and ooze some "juice" when it's squashed.

Tim, Barb is right....scale insects (most species) remain on the plant even after they (the insects) die, either from chemical intervention or by natural causes.

I do have to ask, Tim, about the ratio of oil to water as it seems very high. Of course, there are many different brands of hort. oil on the market, each with its own label directions. My point is that you need to follow those directions carefully regarding the mixing rate and the frequency of application. Even organic horticultural oils can damage a plant if not used correctly.

I meant to add a picture. The ratio is on the top end. They didn't die with a lower dose.

If it's been several days, they are probably dead. Maybe try hosing the plant off to see if the dead ones wash off at this point. That looks like either Cottony Cushion Scale or Mealy Bugs, the hort oil should take care of both.

And if the oils don't work, I can bet you a nice alchohol spray then after ten minutes rinsing your tree off will, immediately)

MIke

Does Hort oil have a shelf life?
I will blast all off with water. I know many are still alive, I can
See the ants farming them.
I will try the alcohol if necessary. This is a dwarf, with fruit
of excellent flavor. I won't let the scale have the tree.

Imidacloprid will kill them for sure, all bugs sucking a treated tree will die.
But it is systemic (hence its effectiveness), it will need a resting period before eating the fruit.

I blasted them with the hose. Problem is, I have seen ants carrying them back up into the tree. I will keep an eye on them. Thanks for all of your assistance.
Tim

Repeat hosing as needed.

yeah i would hit it with alcohol spray and then rinse do that several times for a 2 to 3 weeks and you will certianly end up with a scale free tree ants or not the alcohol kills them on contact so any that get back on will be dead with the next spray and rinse.