Cactobrosis fernaldialis, the blue cactus borer, is a species of snout moth in the genus Cactobrosis.

It was described by George Duryea Hulst in 1886, and is found from Texas to southern California, where it inhabits deserts.

[2][3] Adults are on wing from late March to April and again from July to November.

The larvae feed on Ferocactus wislizeni.

This Phycitini-related article is a stub.