。
She hates bugs.
Literal
She [topic-は] bugs [subject-が] really-hates.
大嫌い ('hate / strongly dislike') is the emphatic form of 嫌い, prefixed with 大 for intensity. 虫 covers a broad range — insects, bugs, worms, and creepy-crawlies in general. が marks the thing disliked as the subject of the emotion. A simple but strong statement of aversion.