On Oct 9, 2010, palmbob from Acton, CA (Zone 8b) wrote:
This is a serious cycad pest, and there are not a long list of serious pests for cycads. Scale often attacks cycads, but rarely does it do much damage. Yet this particular species can kill a plant if not taken care of. It is of particular danger to Cycas species in non-endemic areas (some Cycas species from Asia seem more resistant to this infestation). But it can also affect Encephalartos species (not nearly as badly in most cases, but some are particularly sensitive to it).
Some recommendations to kill scale include systemics, topical insecticides and oils. After scale dies, it will remain on leaves. Spray leaves with sharp stream of water 10-14 days later to remove the dead insects. Recheck frequently for reinfestation, which is extremely common.
for faster results, cut all leaves off affected cycads as close to caudex (trunk/stem) as possible. Put all leaves in trash immediately. Spray remaining plant well with whatever you have. By time new leaves come in, the threat will (we hope) have passed.
Note that this scale, though primarily a threat to plants from the genus Cycas, can infect most cycad genera.
This scale has wiped out sagos in south Florida since its introduction in 2000 or so. It infests roots and hidden areas beneath plant parts on the trunk. I call it the Al-Qaeda, sleeper cell insect. Safari (dinotefuran) is the only systemic which really smokes this scale, see: http://collier.ifas.ufl.edu/CommHort/CommHortPubs/Cycad Scal...
Doug Caldwell, Collier County UF Extension