"他讨厌昆虫"用英文可以表达为"he hates insects"或"he is insectophobic".

"Hate"是英语中的动词，意思是"憎恨、厌恶、讨厌"。"Insect"是英语中的名词，意思是"昆虫"。"Insectophobic"是英语中的形容词，意思是"恐昆虫症"。

举几个例句：

He hates insects and won't even go near them. 他讨厌昆虫，甚至不敢靠近它们。
She is insectophobic and gets very anxious when she sees a spider. 她很怕昆虫，看到蜘蛛时会感到很焦虑。
His fear of insects is so severe that he can't even watch a movie with them in it. 他对昆虫的恐惧是如此严重，以至于他甚至不能看有昆虫的电影。