This creature first invaded our large greenhouse several years back and has travelled through it gradually in what appears to be a colony. We do not see it/them moving about but where they settle is obvious. Each individual appears to build a sort of membrane or shell over itself at a fixed location and they feed by sucking sap from the vegetation, which in our case started on the peach tree and went on to the grapevine (both high up and with large spread). Below where they are their droppings build up as a sticky liquid covering everything below. I have tried spraying the tree and vine with insecticide in the late winter before they can be expected to move, mate and set up house, but with very limited success. Does anyone know what these mites are (actual name), where I can learn their habits and weaknesses, and (best of all) exactly what will work to eradicate them ?
Hi Karl,
It sounds like you have some type of scale insect. You don't mention what you used as an insecticide, but horticultural oil works on scale insects. It's usually best applied in late winter before they start to move about. Here's some organic recipies you can make.
http://www.dirtdoctor.com/view_question.php?id=204
Maybe someone will come along who will know which one you have.
Good luck,
Newt
Many thanks for these useful answers - the only unhelpful one appears to have been edited out "in a puff of smoke". It seemed to be aimed at challenging me, not the insects, so no real loss. I will attempt the solutions suggested. Thanks again.