Tannish patches on leaves?

[luvcraftiann]

Hiii sorry if this ends up just being an overwatering issue or something the plants im talking abt are technically not mine and im not in charge of them being watered because of that

basically dead (?) tan patches have started appearing on our tomato, pepper, mint and strawberry plants. they start as small white spots and then get larger and browner as time goes on. the most affected leaves have small black dots on the undersides of the patches.
the plants are in a greenhouse but it doesnt have a working door since we cant afford one right now and the weather keeps going from really hot to cold (not frosty though) from day to day. theyre also still growing and making runners/berries/tomatos too.

basically what are they, can i get rid of them (without throwing out the whole plants) and could they potentially kill the plants? any help is appreciated thank you

 

[Anniekay]

Hard to say for certain, but those little black dots on the undersides of the leaves look like sawfly eggs, or leaf miners to me. Are you seeing little 6 legged hairless caterpillars crawling around on the leaves anywhere?

 

[luvcraftiann]

Hard to say for certain, but those little black dots on the undersides of the leaves look like sawfly eggs, or leaf miners to me. Are you seeing little 6 legged hairless caterpillars crawling around on the leaves anywhere?

there are caterpillars, but (at least according to my mum, i haven't seen any and she's been picking them off) they werent 6 legged. about the width of a pencil, and as they ate more and got fatter they turned from green to brown man i hope its not leaf miners they gross me out lol. thank you!