Bug ID please. Pictured on my Opuntia cactus and others in garden have these bugs. Any idea what bug this is? Is it harmful to the garden cactus? Should I treat the area? Thanks for any input from ya'll!
The bugs are fascinating. The white stuff is cochineal scale. It will spread like wildfire to all types of opuntia. The Mexican natives used it to make pink dye (scratch one). It comes right back after spraying them off and eventually leads to maggots infesting the inside. The only thing that I know works fast and true is Malathion.
Those are actually immature specimens.
They won't kill the cactus as far as I know, but they 'suck' on it and leave unsightly discolored spots. I get them about once or twice a year. I used soapy water to wash them off after just hosing them of just made them come back. The soapy water seemed to get rid of them, but I have never had a lot of them.
The mature insect can get pretty big 1/2-3/4 of an inch or so. You can find plenty of pictures on bugguide.net when you look it up.
I am actually not sure that the white spots are made by cochineal scale I have the same cactus and I think it has big raised white Glochids, but I will check that when it is light tomorrow morning.
I looked at my specimen of the opuntia in the picture this morning and those while bumps around the glochids are natural not bug/scale related.