Wednesday, June 29, 2011

Summertime is for bugging horses

When it comes to insects, you have a short list of options: manage, protect, and avoid. Management may involve insect traps and poisons and insect habitat reduction. Protection includes repellants, masks, blankets and cover. Avoidance means knowing how to stay away from certain insect hangouts.

What you may or may not do depends on the insect, said Phil Pellitteri, UW-Madison entomologist. And there are plenty of insects for horse owners to cope with during the season from mosquitoes to gnats, to ticks, to flies, to wasps and more.

“Wisconsin has two basic types of ticks,” Pellitteri said. “The black legged, or deer tick, that’s known to spread Lyme’s Disease and the wood tick. Deer ticks are present about anytime there isn’t snow on the ground. Wood ticks tend to be more plentiful in the spring and early summer.”

Ticks can show up in many places but Pellitteri said deer ticks prefer woodlands and forests while the wood tick tend to show up more often in grassy edges. There are chemicals that repel and kill ticks effectively, he said, but there always are more ticks. Mowing grass and sticking to wide, well groomed trails can also help. Contact your veterinarian if you have concerns about ticks and diseases.

“When it comes to mosquitoes, life is tough,” Pellitteri said. “We have 54 known types of mosquitoes in Wisconsin. There are sprays and fogs that’ll knock down mosquitoes for a while but they can blow in from 10 or 15 miles away.”

For mosquito management try to eliminate areas of standing, stagnant water and keep watering equipment clean and full of fresh water. Repellants, masks and blankets and shelter should help your horse cope with mosquitoes. Mosquitoes are disease vectors so for concerns about West Nile Virus and east and west equine encephalitis you should visit with your veterinarian.

“Gnat is a generic term,” Pellitteri said. “Entomologists use the term noseeums for a family of small flies that include the black fly. That’s commonly what you’ll see swarming around the head. But noseeums vary by how they feed and the type of habitat they use.”

The black fly stabs and then feeds on the seeping blood. They’ll swarm up an animal’s nose, ears and mouth creating a nuisance and possible health issues. Black flies breed in moving water so people with horses near streams are more vulnerable. However, the black fly can travel on the wind 40-50 miles, Pellitteri said, so they can show up anywhere.

Other variants of the noseeums breed in the edges of ponds or flooded areas in what Pellitteri calls the “muddy interface.” While similar in annoyance value to the tiny black fly, the noseeum rarely strays more than a few hundred yards from their muddy habitat.

“You’ll see them most often at dawn and dusk. They’re weak flyers and dawn or dusk is typically when the wind drops down. Any kind of breeze usually takes them away,” he said.

One of the curiosities with the gnat and noseeum pests is its distain for going indoors. Horses can escape by going in the barn or a run-in type of shelter. Horse and rider can get away from the noseem clan by riding in an indoor arena where possible.

Masks, blankets and repellants may also help horses deal with black flies and noseeums. It’s also possible to slather on a thick, viscous material such as petroleum jelly to put a protective layer between the horse’s skin and the insect’s bite.

Flies such as the stable fly (heal fly), deer fly and horse fly come right to the top of the list of nuisances for horse owners, Pellitteri said. Stable flies are a species onto themselves while Wisconsin is blessed with more than 20 variations of the horse and deer fly families.

 “The stable fly has a mouth part shaped like a stiletto knife,” Pellitteri explained.  “They’ll buzz around the feet and legs. It’s a quick hard bite.”

While the stable fly won’t breed in manure piles like many kinds of flies, they’ll reproduce in “green manure” such as piles of grass clippings, straw piles or wet hay piles. Keeping hay feeding areas dry and clean helps but stable flies can migrate 200 or more miles, Pellitteri said.

You can kill stable flies with insecticides but they’ll continue to migrate into the area if they have a breeding spot. Horses and riders may find some relief going indoors or finding shady places. Repellants may have some value but protective blankets and masks usually don’t cover feet and legs.

“Horse flies are large. In fact Wisconsin has a humongous horse fly that’s about two inches long. Deer flies are much smaller and often it’s the deer fly that’ll swarm around you in clouds,” Pellitteri said.

Deer flies reproduce in marshes and as adults will tend to move into wooded edges. “Deer flies are attracted to movement and can fly 30 miles per hour. And when they see a horse coming they’ll be there quick and make a painful bite,” he said. In fact, deer flies can take enough blood to cause anemia in unprotected animals.

There is a trap on the market that can help if you’re located within a couple miles of a marshy area. Otherwise you have the usual options of blankets, masks, repellants and riding indoors.

Then there are stinging insects such as wasps and bees. Pellitteri says your best bet is awareness and staying away from nests and hives. Watch especially for the insects that live in nests. Disturbing a nest can bring out an angry swarm.

“A paper wasp nest 20 feet up in a tree out in the woods shouldn’t be any trouble so just leave it alone. If they happen to build a best in a bush near the barn door then you probably have to get some help and do something about it,” Pellitteri said.

Bumble bees sometimes find a place to nest in crevices between bales of hay or straw. Be on the lookout for activities, he suggested, and seek professional advice before taking on a nest.
 For help and more information contact the Insect Diagnostic Lab:

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