After seeing the devastation these grubs cause in Opuntia, I was wondering, Do they ever attack other cacti genera? I'm assuming no, but I'd like to know if you've ever seen them on anything else. Thanx

Just opuntia I believe. I received some opuntia cuttings ages ago that had the little bugger in them. Apparently they were introduced to australia in the 20's as a means of controling the prickly pear. I just cut the sections containing them out and they did just fine.

They cause massive damage to the prickly pear, I would hate for them to attack any of my other plants

You know we could do massive damage to the prickly pear ourselves - the pads (without spines) are purely edible, and in fact we should be eating it!

It appears we're not the only country to have introduced the moth and they appear to have controlled the opuntia significantly.

I remember in 1996 I was studying biological control, and this came up time and time again as one of the most successful bio-controls of all time. I believe that is because the caterpilla is so exclusive.

That's good to hear. just the thought gives me shivvvers