Every year my 4 cordon pear trees get these black tiny slug like insects all over their leaves. They suck the chlorophyll out of the leaves and ruin them. I squash as many of them as possible but wonder if I can get rid of this recurring problem. I don’t like using chemical controls if at all possible.
Although unsightly, the damage is not that significant, especially on trained trees that tend to over-grow in any case.
But if the damage is causing lack of growth and crop, any contact insecticide will give control, including organic kinds.