Lord of the flies

In many parts of the country when the golf season is in full swing, so is the horsefly and deerfly season. These pesky critters flying around your head are more than just a distraction -- their bites are downright painful. Staff members were bitten on the face, neck and hands every day. Some were swinging so hard at the deerflies trying to kill them, only to miss the very quick pests and hitting their own faces, causing bruises. These pests made it very difficult for my staff members to perform their daily work activities, but more importantly the flies were affecting golfers.

I first noticed the problem while constructing Windy Hills GC in 1994. We have several-hundred pine trees on the nine-hole course, with many natural wet areas surrounded by the Battenkill River. Hoping the flies would go away when the course was finished, I ignored the problem. Unfortunately, they did not go away.

In the Northeast the biting fly season starts about the middle of May and runs sometimes into the middle of September. With each passing year we found the deerfly problem was becoming steadily worse. It became the No. 1 complaint with both our members and the daily fee customers as the deerflies and horseflies increased in numbers from year to year. As both the superintendent and course owner, I was extremely alarmed by the drop in golf rounds when compared to the previous summer. Fewer golf rounds translate to lost revenue, and worst of all, our course was getting a reputation of having a bug problem.

As superintendents, we are trained to deal with most any problem. Too dry, add irrigation; too wet, install drainage. We use chemicals and fungicides for turf problems and diseases. But what do we do about flying pests? It became very frustrating for me to have a problem that seemed to have no solution. Talking to some superintendents and people in the pest industry would lead you to conclude that these flies are a fact of nature and, like rainy days, there is nothing you can do about it.

That was not good enough for me.

I had to use desperate strategy. I had to think like the deerfly. I was obsessed and determined to get rid of these pests that were ruining my livelihood. In order to do this I had to learn everything about the deerfly and horsefly I could.

A search of the Internet offered both concern and a possible solution. I found a number of sites with biological information about these flies that were helpful. Unlike mosquitoes, which have a "hypodermic needle" to suck up your blood, the horsefly and deerfly (both in the family Tabanidae) have mouthparts that are blade-like for cutting through the skin. The fly then sponges up the oozing blood. The bite is painful because it inflicts a lot of damage to the skin.

Like the mosquito, only the female bites. Deerflies however, only feed during the day, so hunting for a blood meal occurs at the very same time the golfers are on the course. Horseflies lay their eggs on stems or leaves over the moist soil that surrounds many golf courses. Eggs laid on leaves and grass blades escape many of the predators that would eat them if they were laid directly on the soil. In one week or so the eggs will become the larval habitat. Over the winter, the larvae move to the soil where they may live more than a year and can travel considerable distances.

Horsefly larvae are interesting because they are savage predators, capturing their prey (usually other insect larvae) with large, sharp, sickle-shaped mandibles and paralyzing them with an injection of venom like a rattlesnake. I also learned horsefly larvae are capable of a painful bite if they are handled. Deerfly larvae have a similar set of mandibles with venom glands, but scientists aren't sure what they eat.

One serious control problem I found during my research was that the adult flies are capable of flying more than a mile from their breeding sites and can fly at 60 mph. These sites are generally near swamps, marshes and along ponds and stream banks, all of which can be found near or around my course.

As I continued my research on how to eliminate the deerfly, the entomology Web sites all shared a common theme. No satisfactory chemical control has been developed to eliminate these insects. The preferred wetland habitat that supports the larvae makes it impractical and environmentally unacceptable to treat breeding sites. Adults do not rest on predictable surfaces, so residual insecticide treatments are not effective. Fogging or aerosol insecticides only knock down what is present at the time of the treatment, but more flies can migrate into the area within minutes.

After reading all the information on the sites, I was quite depressed. My wife Karen and I seriously discussed selling the course that took us five years to build. After many conversations I again turned to the Internet where I found a different approach to the problem. I located a Web site that had a trap specifically designed for the horsefly and deerfly. Never thinking of trapping these flies, I found that www.bitingflies.com had some very interesting and valuable information that might help me.

The site had studies from a few universities about some successful testing that had been done. According to the site's literature, there is only one time in the life cycle of these flies when they are vulnerable -- when the adult female is looking for a blood meal. She is a visual hunter, and trapping her at this time appears to be the only solution. The trap has a target that attracts the fly, and when it learns the target is not a blood meal, the trap is designed to take advantage of the fly's instincts. The trap then leads the deerfly into a captive bottle on the top, where the fly is soon killed by the heat of the sun.

Very curious and hopeful, I called the number on the site, (888) 685-2244, and talked to Neil Newman, the owner and developer of the Horse Pal fly trap. Newman informed me he had been researching horseflies for several years. He went on to say he owned several horses. The horseflies at times were so bad he could not ride his horses and the flies also posed a serious threat to the horses' health.

At $200 per trap, we had questions as to whether this was the answer to our problems, or if we would be throwing our money away. My feeling was that I had no options and quite frankly was very desperate. I had spent the winter months trying to find a solution and felt I had nothing to lose but $200 and maybe some deerflies.

In May 2001 we received our first Horse Pal fly trap. I've got to admit when it was assembled, I said, "If I were a deerfly, I would not be trapped in here." To my amazement, after the first hour we had already trapped several deerflies. In the next few days we were catching approximately 100 per day. By the middle of June we added two more traps and later that month another three. The traps were placed in areas where deerflies were most numerous but out of the way of golfers. We estimate between 600 and 700 deerflies were trapped and killed each day that summer in six traps.

The trap requires virtually no maintenance except the occasional emptying out of dead flies and with proper winter storage can last for many years.

The traps have eliminated about 75 percent of our deerfly problem, and with the increased revenue from the additional greens fees, we have recovered the cost of the traps in the first year. The trap, originally developed for another market, has changed our

... there is only one time in the life cycle of these flies when they are vulnerable -- when the adult female is looking for a blood meal. She is a visual hunter, and trapping her at this time appears to be the only solution.

course dramatically. It has improved our staff's morale, and flies are no longer the No. 1 complaint with our members. Although we have not totally eliminated the deerflies, they are now tolerable.