When Not To Treat
for House Fly
Reaching for insecticide first is the wrong move. Sprays should come only after every non-chemical step is in place, since weak sanitation and poor exclusion are the real causes of fly problems. Treating adults while a manure or garbage source keeps producing new ones just wastes product; the source has to go first. Source: https://ipm.ucanr.edu/PMG/PESTNOTES/pn7457.html