Are you — or should we say your cattle — having “a devil of a time” with face and horn flies this year?
If yes, you’re not alone. If no, feel lucky and keep doing what you’re doing.
“Populations of both horn flies and face flies are higher this year compared to the previous two or three years,” said Bayer Animal Health senior technical services Veterinarian Larry Hawkins. “In fact, it’s been an intense fly year in some regions, from Iowa, Missouri and Arkansas to Virginia, West Virginia and other areas of the country.”
A good year for flies potentially means a pesky year for cattle and an equally pesky year for producers, especially for those who aren’t carrying out a sound plan throughout the fly season.
“Often, late-summer plans are lacking. That depends on the producer, of course, but certainly late summer seems to be the time when we see more issues with flies,” Hawkins said. “Part of that is because August and September are typically the months of peak fly numbers, and if you aren’t prepared to fight back, flies can quickly get out of control.”
But even when producers are carrying out a sound, well-thought-out program, weird things can happen.
“I was at a producer’s farm in Missouri in late July. He called because his fly control program was working very well at two places, but it was not working at a third farm only a few miles away. He was having problems with not only horn and face flies, but also stable flies.”
After touring the three sites, Hawkins was equally stumped because the producer seemed to be doing everything right, from his insecticide program for all three fly species to cleaning up residue around corrals in an effort to keep stable fly numbers in check.
The corral system allowed the producer to spray that particular herd, which proved very successful.
Though sprays can be an important part of an overall system, Hawkins believes that ear tags are one of the most successful ways to combat flies, but typically they only offer about four months of good control.
“Some labels say five, but we’re finding that you don’t get adequate control that last month,” noted Hawkins, who emphasized that the reduced efficacy is one of the issues leading to insecticide resistance.
Because of that, he urges producers to develop a fly control program that supplements ear tag control late in the fly season with back rubs, dust bags, pour-ons, timely sprays and, in some cases, replacing the ear tag.
Feeding an insect growth regulator or larvicide until one month after a killing frost can also be worked into a plan.
Nancy Hinkle, professor of entomology at the University of Georgia, said that an integrated pest management approach is a great way to battle fly problems, but this takes arming yourself with knowledge.
For example, she noted, feed-throughs are an effective way to help prevent fly larvae from developing in manure.
“Some are insect growth regulators that prevent larvae from developing into adults, and the active ingredients have little effect on beneficial insects,” Hinkle said. “But others are insecticides that kill larvae, including beneficial insects like dung beetles and parasitoid wasps.”
Parasitoid wasps, she added, are especially effective in controlling horn flies.
“Consider them your friends,” Hinkle said.
Hawkins agrees, pointing out that producers should always keep six words of wisdom at the forefront. “Stay on top of the numbers!”
It’s vitally important, he said, to not let things get out of hand with fly populations, which means keeping close tabs throughout the season in addition to rotating modes of actions and classes of insecticides.
“It’s very important for all producers to keep insecticide resistance in mind. When you rotate to a different class of insecticide, try to rotate your whole operation at once,” he advised. “This is not always possible, but it’s worth the attempt to help keep from selecting for resistance.”
More information is available at BayerLivestock.com. Always read and follow label instructions.