Although a fly's actual life span is short, no more than a month, their prolific breeding makes their presence seem endless. The biting stable fly may lay 10 to 12 batches of 40 to 80 eggs during her short lifetime. We're willing to try almost anything to get some relief for our horses from the biting pests, and those of us who have tried fly parasites are convinced they are the best method.
Of course, good manure management is crucial to fly control, but many other factors are involved in controlling the reproduction of these winged monsters. In fact, it's not just manure.
A study at Texas A&M demonstrated that a million biting stable flies could develop in the residue of one round bale of hay. Other guilty locations are lawn clippings, moist compost, mulch and gardens. Standing water is great for breeding mosquitoes, as you know. But you may not have been aware that horse- and deer-fly larvae favor shallow water and wet ground, too. That mud hole by the water trough might be nearly perfect for them.
FIELD TRIAL. Last summer, a group of our testers, all living in the same general area in New York, decided to conduct their own field trial using Fly Predators, a specific brand of fly parasites from Spalding Labs (www.spalding-labs.com, 800-706-3116). We found the results so interesting that we wanted to share it with our readers, despite it not being a head-to-head comparison of fly parasites.
Several farms used Fly Predators to control nuisance flies, while others used traditional methods for a comparison. With this method, they decided, they couldn't pass off a "quiet" fly day as being solely weather-related, since they could compare with the activity on an unprotected farm.
Two farms with adjoining property lines showed a dramatic difference. The horses were actually a "crow's mile" apart, but the ones with the predators defending them had hardly a fly problem all summer, while the other horses were standing in the darkest part of their run-in shed, still stomping and swishing their tails.
All barns were kept clean, and some farms picked manure up out of their paddocks, while others didn't. The fly parasites worked as well in either environment. However, the establishments using more diligent manure management seemed to have better control. There also appeared to be a noticeable decrease in the flies that were not listed as being affected by the fly parasites.
One stable that kept four acres clean around the barn, run-in and riding area but did nothing with the manure in their 12-acre pasture had fantastic results. (This farm is a half mile from a small cattle operation and adjoins a nature conservancy swamp, both prime breeding grounds.) They were virtually fly-free all summer, noticing even a strong decrease in face, deer, horse and bot flies.
This stable used a small bag of parasites, designated for one to five horses, and sprinkled the predators on the manure piles. They also made a loop through the pasture, placing parasites on fresh manure in the rough areas.