The casebearer requires high humidity to thrive and plenty of food sources.
So run your Air conditioner and dehumidify the inside air.
Clean everything in sight - spider webs, food crumbs, seal up cracks and crevices. Wasps will kill them but I don't think you want those nests on the outside of the home. There is a chemical I heard of called Physan 20 which kills them with in 10 minutes - you might need to do several applications over the weeks as the gestation period of the larvae can be about 45 to 50 days.
How old is your stucco and how damp is it .. you might have moisture in it. You will need to resolve that issue if you expect them to leave. If your have the house fumigated - get the stucco sealed up and painted.
You said the house was fumigated before you moved in ... done by the previous owners? or you requested it knowing the insects were there ?
I ask this because certain other remedies might be available for you to look into.