Hi y'all ! I have a bunch of gorgeous ( and formerly gorgeous ) sempervivums in nursery pots that have lots of synthetic fertilizer beads . Didn't have time to plant them properly before freezing temps got here . Some were looking ragged . So I looked under my microscope and saw brevipalpus mites . Also called false spider mites or flat mites . They're invisible to the naked eye . But I'm so shocked that these scum bags can survive freezing and thawing over and over . We have nights in the 20's and days in the 60's right now with tons of rain . I've kept them under the overhang. But they've managed to get wet from the angle the rain came in . I broke down and bare rooted a few today. But it got dark on me . So I sprayed the rest with sulfur. Just letting everyone know that if you notice a bad downturn in your semps and lots of black stippling in your leaves , break out your microscope if you have one . Does anyone think it will burn them to have given a good spray of sulfur since they have the fertilizer beads in the soil ? I know from experience that sulfur is the best bet for these mites . I battled them on my indoor succs for 2 years straight. Never dreamed they'd be living during winter . We've had weeks where it was in the teens and the suckers are alive and well . Hope nobody else is getting them . Right now , on YouTube there are several videos talking about flat mites on Hoyas . But up til now , no videos about them . So I think they're a new pest that's becoming a problem. Since they can't be seen with the naked eye , they're the devil . They can destroy plants in no time if not treated . The only ones that seem to be affected are the ones that are in the nursery pots with the synthetic fertilizer beads. I read that synthetic nitrogen is what causes the mites to attack. The ones that I have in my own home made soil seem to look pretty good. I am trying to decide whether to spray them as well. I probably won't because they look so nice. Wish I'd just bare rooted them back in November. But we had a streak of freezing weather for a week or two and I was worried that messing with the roots would kill them since it's not their growing season. I always wash the soil off the roots on new semps and dry them for a few days then put into my own mix . Some were looking so bad that I just went ahead and cleaned them really good and sprayed them . Then sprayed the ones still in nursery pots cuz it's dark now and I have the crud . 🤣. I should be resting. But I can't let my semps get eaten. Some have bad mealybugs too . They're doing fine this winter here as well . I despise them . Anyway, just wanted to warn y'all. This is an old thread. May not even get seen. 🤗