All in a day's work

When night falls over the Yuma area, bright yellow planes can often be observed swooping over power lines and diving low over farm fields. While the maneuvers are impressive and enjoyable to watch, it is just another day at the office for the pilots.

Known as “crop dusters,” the pilots are hired by area farmers to apply pesticides, fungicides or herbicides over fields of lettuce, broccoli, spinach or other crops to make sure the food will make it to grocery store shelves around the world without being rotten or filled with bugs.

“It's not sightseeing – it's busy work,” said Curt Hill, a crop duster employed with Tri-Rotor AG Services, based in the Somerton area.

“To do an efficient job, you are making a plan as you go — where your next turn is going to be and where you are going to make your next swath.”

In addition to dodging trees or power lines, the crop duster must be aware of the level of chemicals remaining in his hopper and how much fuel is left in his tank in order to plot the most efficient course possible.

And when the pilot releases the chemicals over the crops, at about a height of 10 feet above the ground, he must be observant of which way the wind is blowing and also of the backwash from the propeller.

“The wash of the airplane has to spread the spray out without making a rooster tail and blowing it up in the air,” Hill said.

The crop duster is tasked with delivering a consistent amount of chemical evenly over the entire field, because any spots missed can lead to insect infestations or other problems.

“You can't go in and do a yucky job,” Hill said. “If they go back and they've got worms in their lettuce because I've missed the edges… that follows me. I sign that field every time I fly.”

Being a crop duster isn't for everyone, said Matt Fieldgrove, manager of Tri-Rotor AG Services.

“We get a lot of pilots out here, and not everybody can do it. You have to really want to do it because of the hours you have to work, and the effort it takes. We are not just flying to fly. We don't get paid to fly. We get paid to apply chemicals.”

The crop dusting business began in the 1920s when the first pilots conducted the “aerial application” of chemicals over crops in modified biplanes from World War I.

In those days, the pilots had to rely on “flagmen” on the ground who waved a white flag to communicate which portions of the field had been “dusted” and which parts hadn't, explained aviation writer Roger Guillemette in an essay about the profession.

“One of the more hazardous jobs in crop dusting, the flagman risked injury or death from the low-flying airplanes in addition to the insidious hazards of exposure to the chemicals being applied,” Guillemette wrote. “Flagmen (and crop-duster pilots) often joked that they were immune from mosquito bites following an aerial application of pesticides.”

The first airplanes used by crop dusters posed safety hazards because they were lightweight and had weak frames, Guillemette continued.

After World War II, pilots had access to a new generation of aircraft, including the Boeing/Stearman Model 75 Kaydet two-seat biplane. Such planes had been built with stronger frames and more powerful engines, making them more suitable for crop dusting.

During the 1950s and 1960s, Yuma entered a “Golden Age of Crop Dusting” as many pilots took to the skies in biplanes such as the Kaydet to crop dust area farms. It was during this time the crop dusters began using liquid spray instead of powders.

Herb Curtin, the nephew of crop duster Robert “Bob” Wilbur, was one of the flagmen on the ground during Yuma's Golden Age. “I would line them up with a large white flag as they were coming at me,” he said in 2009. “One or two planes (would take a pass) then they would come back the other way, on and on.”

The crop dusters led very dangerous lives, and were known to drink heavily. Many died because of their choice of profession, Curtin said.

Among those who died while crop dusting in the Yuma area were Betty Tank, Steve James and Lawrence Spain.

According to Curtin, Tank died when her plane crashed near Castle Dome, and James hit a cottonwood tree near Crane School.

Dorothy J. Spain, who died in 2001, recalled the death of her father-in-law, writing, “After the war (Spain)... was also a duster pilot. One day he sprayed a field with chemicals then turned his plane back into the spray and was overcome by the fumes. He flew into a tree and was killed.”

Yuma crop dusters of this era who survived their flying careers include Bob Wilbur, Don Harmon, Orville McVey, John Wilbur, Marvin Walker and Don Galyen, although none is still living today.

Crop dusting has continued to evolve over the years, and the planes are much more advanced and safer, Fieldgrove said.

“The technology has come a long ways. When we first started out, we were using flaggers and Cessna 188s. There was no air-conditioning and they were all piston-driven aircraft. Today they are all turbine (engines) with air-conditioning. Everything is done by GPS and flow control. Everything is done by computers now.”

And the chemicals currently used by crop dusters “have become a lot milder than they used to be,” Fieldgrove added.

“Everything now is basically water-soluble. It used to be oil-based and lasted for quite a bit longer. Now everything is water-based, or alcohol-based. It is easier on the environment and lasts less time.”

In the past, the crop dusters would spray each field on a weekly basis following a rigid schedule. Now, they only spray when a pest control advisor (PCA) in the field recognizes a threat to the crop. The PCA then calls for a specific chemical, and in a certain amount, to combat the individual problem.

“The chemistry has gotten better and they've made the chemicals to where they are pinpointing a particular bug … so the amounts we are putting on now a lot of times are just ounces per acre,” Fieldgrove said, explaining a few ounces of chemical is mixed with about 10 gallons of water before being sprayed on a field.

“Once it is mixed and put in the airplane, the toxicity level is very minute. The chemicals, as long as they are handled safely, are not much of an issue anymore.”