Actually BONAP shows both Y. flaccida and Y. filamentosa as "adventive", not native but introduced from a nearby state. Even though they are not native to your state, they are growing wild their which means that Yucca Moths are using them are they would not be growing there. The moths may use any Yucca available, but since those two are what grows there (Y. flaccida seems to be the most abundant) they would be my first choice.
