White fly on the mandarin

This afternoon I notices a bunch of white fly covering the undersides of leaves on the mandarin tree, which is still very small. Some growth new this autumn was curling and unhealthy. There were small patches of white fly also on the nearby valencia. Daughter and I spent most of an hour rubbing off white fly by hand and rinsing the leaves. When we finished, I poured worm tea over the entire tree and into the soil. Hopefully this helps turn the tide.