What’s going on with my pak Choi?

[KateG]

Hello!
I am growing win-win choi which (from what i understand) is a pak choi variety. it was doing really great until a couple days ago. its got little holes in the leaves but it also has all these yellow powderly looking dots/clusters all over them.I found a worm on one of the leaves (cutworm maybe?) so that might explain the holes but i cant figure out what the yellow powdery bits are? Im fairly new to vegetable gardening and im not sure how to address this issue. Thanks!

 

[Marck]

Greetings, welcome to the Forums.

Yes, this is caterpillar (Lepidoptera) damage on your Win-Win Choi (Brassica rapa Chinensis Group cv.).
Both the holes and yellowish abrasions on the leaves are made by caterpillar mouthparts.
The black granules near the holes is frass (caterpillar feces).