On warm days during the winter, they move out of hibernation areas into the living quarters where they are a general nuisance. Most of the time they are found resting on plants, fence posts and other objects.
If the average number horn flies per animal exceeds 200 Figure 2 , the economic threshold has been exceeded and control should be considered. The economic importance of these nematodes seems minimal.
Both cows and calves must be treated if control is to be achieved. As livestock producers ponder when to send cattle to pasture another consideration is what livestock pest control options are available for this summer.
The face fly closely resembles the house fly except it is slightly larger and darker. This compound is an insect growth regulator IGR , which is safe, and cross-resistance does not develop.
Insecticides for use in oilers are usually diluted with No. Producer Question from 2012 Q: If fly problems are bad, it may mean you put a tag in the cow and calf. Pinkeye is a highly contagious inflammation of the cornea and conjunctiva of cattle. Not all oilers are built the same, so check construction.
The horn fly is a blood feeding fly that is located on the shoulders, back and belly region of cattle, they take some 20 to 30 blood meals per day and the only time they leave an animal is when the female deposits eggs in fresh cow manure. Ear tag efficacy declined over time but the point where the economic threshold was exceeded varied among the products tested.
One other aspect of economic importance of the face fly is their nuisance value to homeowners when they overwinter in the home. However, most horn fly populations in Nebraska are resistant to pyrethroid insecticides. The effect of stable flies on weight gain performance of pastured cattle is similar to that of livestock in confined operations.
Both oilers and dust bags should be checked periodically to assure that insecticide is being properly dispensed. The complete life cycle of the fly from egg to adult can take 14-24 days in Nebraska during hot weather. Face Flies The face fly, Musca autumnalis DeGeer , is a robust fly that superficially resembles the house fly.
Also available are oilers that can be filled with a fly control ingredient.
Control products recommended as animal sprays are: The animal pictured at right has 314 horn flies and population numbers of several thousand of flies can often be observed during the summer. Drovers May 18, 2011 01: In addition, horn flies have been implicated in the spread of mastitis. Related on Drovers. The complete life cycle, egg to adult, can be completed in 10 to 20 days during warm conditions.
Proximity to untreated cattle and inadequate consumption by cattle are two factors that can contribute to poor fly control. The bags can be gradually lowered to the point that calves are also treated by them after the cows freely pass under them.