spider mites be wee little red arachnids. so small, they are very hard to see with the proverbial nekkid eye. you know when you've got 'em because they cause your plants' leaves to curl inside out. your problem sounds more like pepper maggots, i'm thinking. pepper maggots are usually white or yellowish white while the adult flies are yellow striped with dark bars on the wings. that's just a guess. if that's what they indeed turn out to be you can use rotenone or malathion on them. good luck!