Monitoring for fly larvae and pupae is important in determining specifically where flies are developing (breeding), and in order to use cultural and chemical control (larvicides) effectively.
Locating fly larvae is laborious but it must be done in order to know what changes in manure handling and facilities maintenance may be needed to reduce fly breeding.
It is also necessary in order to know precisely where to apply larvicides.
The only practical way to monitor for fly larvae is to examine likely places and remove portions of manure, silage, bedding, etc., for closer examination. The large third-instar larvae and brown pupal cases can be seen easily.
All possible breeding habitats should be inspected. Particular attention should be paid to manure accumulations in places that are difficult to clean, as well as spilled feed, silage, feed bunkers, around waterers, hay racks, under margins of hay bales, etc.
Once the fly breeding spots (where fly larvae are seen) are detected in a facility, they can be given special attention during routine monitoring.
Breeding sites can also be larvicided at the time of monitoring, if necessary.
Since the life cycle of the house fly and many other species is only about 7–10 days in hot summer weather, monitoring should be at least once a week and preferably twice a week.
This can be integrated with a systematic overall inspection of the facilities and animals, to detect any animal health or equipment problems.
Such routine inspection is a sign of good herd and flock management.
