Update

So after digging around I am 95% sure that these little critters attacking my seedlings are thrips. It is really unfortunate as they seem to have infested all 50 pots with little lithops seedlings to varying degrees. I really don't want to use a pesticide and I'm looking for alternate ways to control the population. Since I keep the pots outside on the balcony, perhaps I should be looking into putting other plants out there that attract beneficial predators? I've also tried spraying three or four pots with insecticidal soap - I suppose I could spray all of them and then even resort to an insecticidal soap bath, fully soaking the soil of all of the pots, if things get really out of hand. Thoughts??

Brent

I see that so far yo didn't get response...I do not know much about Lithops, and never grew any from seeds.

Here is article I found about thrips - not sure if you are interested to read, but CLICK HERE if so.

Regarding white spots: spider mites are tiny, but move around fast. Maybe you can check with magnifying glass/loupe if there are any. I have only few Lithops, and luckily didn't have to fight any bugs so far.

Hey rina thank you for the reply, I read through the article and it was quite helpful. I actually purchased some minute pirate bugs, so they should be arriving today or tomorrow. I will let you know how they do in controlling the population. The thrips have killed a few of the weakest seedlings and seem to be slowing down the growth of some of the others. Lately I've noticed some natural predators like jumping spiders and I'm hoping the booming thrip population will also attract other predators. I've used some insecticidal soap on some of the pots that seemed the hardest hit, but they haven't eradicated the thrips as they can simply migrate back over from pots that I haven't treated. I'm trying to avoid spraying all 50 pots until it seems absolutely neccesary.

From what I read, thrips are not easy to eradicate with all kinds of spays, so hopefully beneficials help. Tiny seedlings are likely more vulnerable. There was lots in that article I didn't know, and I found it quite interesting.

I am interested to know how much predators help, pls. post a follow-up. Wish you success.

Hey Riña. Quick follow-up a few months out. I ended up adding a package of around 500 or so (rough estimate) orius laevigatus out onto the planta on the balcony. I observed the orius quite closely, and never observed them stalk or attack a thrip which they would pass by or even bump into. Within a few days all of the orius flew away so they ended up being fairly useless. I still have thrips attacking the lithops seedlings and a few undoubtedly succumbed to them, but as the seedlings have grown they seem to be sustaining less damage, particularly the ones that have now developed adult lithops leaves. I’ve also observed that the population of jumping spiders has increased radically around the lithops pots and they are presumably feeding on the thrips. They haven’t eradicated the thrips by any means, but their population seems to be slightly more in check. Now that I have other flowing plants min the vicinity of the lithops there also seems to be more beneficials around in general.