Fly Control

     Everyone loves 2 for one. Today I am going to discuss the seasonal fly control topic. But almost everything you do for fly control helps toward mastitis control, cow comfort, and/or higher milk production. In addition, fly control helps with pinkeye control. So, you get more than 2 for one.

     There are two mutually exclusive ways to control flies, chemical control and biological control. I say mutually exclusive because chemical control usually interferes with biological control. Chemical control depends on the application of one of two chemicals available for application directly to lactating cows, Cylence (cyfluthrin) or permethrin in one of its many brand name or generic forms. But Cylence can be irritating, especially on Jersey cows. It has been around for quite a while and there may be some resistance developing. Permethrin has been used so much for so long that resistance has developed, especially in the south eastern United States, according to Lane Foil, an entomologist at Louisiana State University. Now, resistance does not mean that the fly sprays do not work at all. Let’s say that the permethrin products will still kill 80% of the flies that are contacted. With houseflies that might be good enough, considering that it takes about 300 flies per cow to cause a 2 pound per cow drop in milk production. It may take 2 weeks for the house fly population to build back up to economic levels. But when it comes to the biting stable fly, 80% may not be anywhere near enough when only 2 flies per cow can results in an 8 pound per cow drop in milk production. Most products, including Cyclence, are not labeled for control of Stable Flies. So, you think you can add scatter baits to the chemical control program to get the remaining 20%. Scatter baits do nothing to control biting stable flies and house flies seem to develop resistance to scatter baits faster than resistance to sprays, maybe because the sprays will at least drown some of the flies. Recently, the next generation of scatter bait, that beats the resistance problem for now, seems to cost twice as much as the previous generation that does not work so well. Are you ready to double your budget for fly control? Note that chemical applications do nothing in the 2fer category. That is they do nothing for mastitis control, and little for cow comfort and higher production other than that little bit associated directly with house fly control. In addition, they tend to wipe out the biological control from parasitic wasps that attack fly pupae and the fly egg devouring hister beetles and earwigs. This is what leads to the decision to focus on biological control of flies.

      For biological control of flies start by stopping chemical applications, especially feed through products. Allow effective populations of parasitic wasps to attack the pupae and earwigs and hister beetles to eat the eggs. To do this successfully you may need to double your diesel bills and keep the corrals in really good shape. Flies need moisture and food to thrive. Yes, biting stable flies also need blood to thrive. But their larvae need damp manure and old feed to survive. Keeping the corrals clean and dry will also help with mastitis control.  A great 2fer. But keeping the corrals clean down to the rock may reduce cow comfort. This is where your diesel use comes into play. To control flies you need to keep a manure pack as dry as possible by harrowing every day and dragging wet manure and old feed out of the shade into the sun to dry. You should be leaving enough dry manure to cover the rocks and provide a soft bed for the cows in drylot situations. In addition to attacking the fly larvae (maggots) through food and moisture management, you can also attack them with a fungus provided by Balance. Balance can be applied to areas where adult flies and their larvae are found. Early season applications result in good fly control and build up of the fungus in the environment. Balance also attacks adult flies that are also susceptible to fly tapes and Stable fly traps. You can aid adult fly control without harming the beneficial insects through limited application of premise sprays or Balance to blue and/or black cloth or plastic fly targets. These targets attract the adult flies to concentrated applications of fungus or chemicals. But why bother with chemicals when a comprehensive biological program can get the job done and promote safe and sustainable agriculture? Just remember to provide a good environment for the natural predators to attack the larvae and eat the eggs while the fungus works on the adults and larvae, all four phases of the fly life cycle.