Occasional insecticide treatment to control adult flies may be needed as well as occasional spot treatment of manure to control maggots. Removing the manure from under one row of cages at a time instead of cleaning an entire building will leave a stock of beneficial insects and mites to move into the new manure. The manure that is removed should be thinly spread in fields, not piled outside the buildings. If good sanitation practices are followed, less insecticide will be needed and that used will be more effective. Acceptable fly control in open houses requires strict attention to sanitation and manure management, supplemented with the use of insecticides as baits, residual sprays and spot treatment of manure for maggot control.
Baits consist of an insecticide and an attractant, which serves to draw flies to the insecticide.
Start spreading the bait as soon as flies begin to be numerous. During the first four or five days, scatter dry bait heavily enough that it can be seen. Continue to put out bait each day for the next week, using smaller amounts than for the first application. After the first 10 days, apply bait every two to four days to those places where the most flies were killed during the initial baiting. To make a liquid bait , mix the proper amount of insecticide with water and add sugar, corn syrup or molasses.