Hello: I have an indoor pencil cactus that seems healthy and happy (green stalks, new growth, sprouts little leaves all over from time to time that then drop off only to sprout anew again in a few weeks time). However, there also seems to be a pest issue that I can't identify or control. When leafing out, the leaves and tips of stems are also accompanied by a healthy sprinkling of tiny black seeds(?) that look like a uniform, coarse grind of black pepper. They don't seem to be insects (no legs or movement), they don't seem to be feeding off the plant (no stem or leaf damage detected) and they just fall right off (like pepper flakes would) when I brush off the plant. At first I thought it was seeds but from online research found that pencil cactus don't seed? The first 3 times it happened, I quarantined the plant outdoors and doused/sprayed it with soapy water. But it keeps happening over and over again and it's unsightly - looking like a massive invasion of tiny black pests. What is it? Should I be worried about all the other plants or is this a normal part of its life-cycle? I wanted to post a photo of the things the next time it happened but my mom's visiting and she unknowingly got rid of the evidence before I got the chance to photograph! Thanks in advance for any help!
