C.N.
Sometimes little kids are phobic about certain things, but they grow out of it. My stepson was terrified of scarecrows when he was little.
Try exposing her to insects where she's in control of the situation - maybe go to a hardware store and buy some crickets in a cage so that she can hear them sing and can see they can't hurt her. Books about insects would be good too, especially ones that explain things like how bugs help plants grow. And of course, explain to her how some bugs are ok to touch and handle and some aren't, just like some other animals and even plants are ok to touch and others aren't. She'll eventually grow out of it.
I'd also stay away from sci-fi and cartoons that feature insectoid villains, as this will likely only add to her fear.