Thrip mystery? I have read as much as possible about thrips in an attempt to understand how to control and prevent infestations. I have not found consistent information. Any thrip experts/fans that can help?

I started looking into thrips when I discovered one on a houseplant last year. I then discovered a small infestation on some of my other houseplants, namely, my Dwarf Umbrella trees (schefflera arboricola).

These guys appear to be just one measurement above invisible to the naked eye. I suspect that the ones I’m seeing are not adults (instar?). They are white, and they favour the tiny new leaves that sprout from the very tips of branches. They don’t appear to like mature leaves, but I do see some damage on them, although small. I may have found an adult today, and it looked most similar to a Western Flower Thrip or a Chilli Thrip. I have not been able to find other species that look similar to these, but I see there are at least 6000 species, so I won’t assume I’ve got an ID.

The mystery is that they seemed to disappear out of nowhere one day. I was battling them constantly—all new growth shrivelling into black mulch—and then they just stopped being a problem. This appeared to happen overnight. I have read about thrips disappearing overnight, but this is supposed to be due to their life cycle, so the problem should reemerge no later than a month after disappearing. Mine disappeared in the spring and only started showing signs of damage last week. They were undetectable and caused no damage for at least 6 months. My home did get very hot in the summer, as I have many plants and south-facing windows. Some pants even suffered heat damage. If the heat (and perhaps some humidity) caused them to go away, does this mean they went dormant? If so, where were they? In the soil? I’ve read about a dormant period, but it appears to be in the winter. Of course, this is for outdoor situations, and I am only concerned with indoor potted plants. Also, I really think they disappeared before the extreme heat arrived. I should also note that the plant that they have reemerged on has been in the same spot this whole time and is completely isolated from other plants, so I’m convinced these thrips are related to the previous ones and not a fresh inoculation.

Another thing I’m curious about is the presentation of damage. All the baby leaves turn black. They do not dry out like the spotty patches on my adult leaves, and they do not leave trials. They retain moisture but are completely soft, black, and limp. I have not been able to find examples of this happening to schefflera, but it seems to be somewhat similar to the spots that arise due to viruses such as INSV (impatiens necrotic spotted wilt virus) or TSWV (tomato spotted wilt virus).

If anyone can provide insight on what’s going on with these guys, that would be great! I love the topic, so please don’t feel the need to limit your responses to advice (although if you have it, I will happily accept it).

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source https://www.reddit.com/r/Entomology/comments/k4hnfn/thrip_mystery_i_have_read_as_much_as_possible/