Help! scale is killing my grapefruit tree

[BobC]

What Disease on my Lemon Tree?

Yes it does at least at certain growth stages. I’ve used all season oil on citrus thinking that since they always have leaves a little lighter oil should be safer. It kills my scale. On a big tree coverage is the difficult part. It kills the ones that get covered but if any remain they eventually spread. I’ve also used several insecticides and mixed oil plus insecticide. The combo is more likely to kill everything.