By Emsandpaul
United Kingdom 
Hello we have 3 acer trees that we have for some years now, only recently we seem to be noticing that covering the trunks and all branches are hundreds of small creatures. I can only describe them as smaller looking woodlice that are rounder and flatter. As we scrape them off they are sucking the sap. Could you please tell me what they are and how to treat/avoid getting more.
Many Thanks
Emma (novice gardener.)
24 Apr, 2011
Answers
Hi Julien,
Thank you for your response, I googled an image and you are spot on. Thanks again will go and purchase some spray.
Emma
24 Apr, 2011
They sound to me as though it could be scale insect, try and srape them off and if you want to use a spray then, ultimate bugkiller is very good if you spray all the foliage it will quickly eradicate these pests, it can be brought in a spray form or concentrate form, and can be purchased from most diy or garden centres and comes in a yellow bottle/sprayer, julien.
24 Apr, 2011