Ashworth's rustic (Xestia ashworthii) is a species of moth. Its colouring is blue/grey and it is mainly nocturnal.
There is one generation in Britain from mid June to August. They are in their larval stage from August to late May of June the next year, feeding mainly by night, but sometimes basking by day in the spring. There are many larval foodplants, usually low growing plants, including common rock-rose, wild thyme, sheep's sorrel, harebell, salad burnet, bell heather, goldenrod, lady's bedstraw, creeping willow and foxglove. It pupates in a flimsy cocoon under moss, among rocks or just below ground.