Recruit some insect battle against flies.
By Boyd Kidwell
"This is war," declares Adele Junfin. She's a consultant with - a south Texas company that sells natural fly control across the United States. If you also feel this strongly about fighting flies, maybe it's time tot turn the battle over to their insect enemies. Parasitic wasps (Spanlangia nigroaenea) are relentless in finding fly eggs and laying their own eggs in them. And, these tiny wasps aren't harmful to people or animals. "Wasps are miracle workers on our ranch," says Kay Cunningham. She and her husband have a cow/calf ranch near Quemado, Texas. Junfin and Cunningham both work for Kunafin. For decades, the Junfin family has raised and marketed predators for natural fly control. As flies have gained resistance to insecticides, cattle producers have become more interested in natural control. Parasitic wasps don’t eliminate flies, but they reduce the population. To be most effective, wasps should be part of a total fly control program.
Parasitic wasps are shipped in the dormant pupal stage packed in rice hulls or wood shavings. At arrival, the pupae should be distributed where shade and water cause animals to congregate. Distribution is important because parasitic wasps don't fly far.
They can over winter in the pupal stage, but distributing new wasp pupae each spring jumpstarts the predator population. However, natural control isn't quick. The wasps lay 6 to 350 eggs per day in ply pupae, but a female fly lays up to 2,400 eggs in her short life.
"It's important to release parasitic wasps early before the fly population outstrips the parasites. Parasitic wasps can work, but it's not a simple matter of releasing pupae," says North Carolina State entomologist Mike Stringham.
In addition to using the wasps, you should also:
- Reduce waste in loafing areas and around feed bunks.
- Dry out wet spots by stopping leaks in confinement bunks
- Limit residual insecticide sprays to barn walls, which kill adult flies while minimizing harm to the beneficial wasps. Biting flies (horseflies and deerflies) require a different battle plan. These flies are called tabanids, and they zoom out of hiding to attack people or animals. Parasitic wasps don't control them, but you can turn the tables on tabanids with traps. Horseflies and deerflies are visual hunters. They see their victims from a distance and fly to them. By resembling animals, traps can attract tabanids and capture them. There are several different concepts in tabanid traps. The Epps Biting Fly Trap uses clear plastic deflectors to bounce circling flies into troughs of soapy water. The Horse Pal attracts biting flies with a low-swinging ball. As the flies turn upward, they are trapped in a pyramid and finally in a collection bottle.