aphids is correct.. they don't pursue roots they go for the green stuff,are there any underneath the leaves,fkers like to hide,,that may have rid them unfortunately gonna have to keep an eye on all them,if they come back yu may have to pest control them,leaves that is ,and mist top soil ,, I use ortho for general pest at walmart,then after few days mist the leaves with water, also wen yu water the plants the poison will get down deeper and kill any visitors deeper down..but i'd see how that does...NS purple.