Help!! I have about 100 cactus in my sunporch and I am having trouble with scale insects. I have had scale for over a year and it is getting worse. Scale is also on my jade plants. What I am calling scale is a white insect that covers the cacti. It grows on the surface between the needles. Do any of you know how to get rid of this pest. I think a systemic pesticide should work well but I don't know where to find one. I don't want to hurt these plants with spray. I can use some good advice. Thank you, Dan Nelson Bridgeville DE zone7