I've noticed that the leaves of some of my petunias and verbenas have tiny shining patches. I've also seen sub-millimeter yellowish worm on the verbenas. In petunias it just some of the inner leaves, but on the affected verbenas it's all over, and they've stop flowering.



Does anybody know what this pest is?

I have no idea of what your pest is but it sounds as if your plants are distressed and need some help. I would try using DE or neem oil first perhaps even just a soap spray. I always try to use a passive approach first before I would bring out a chemical treatment.

I've dug the internet deeper and found it was thrips. The yellow worms I saw was their nymphs. Luckily I have excellent eyesight when it comes to small things. I removed all the flowers to one spot, sprayed with abamectin, and covered it with frost cloth so the bees can't land on them until the abamectin degrades.