State brings technology into mosquito battle
By Darren Marcy
Staff Writer | August 29,2013
Anthony Edwards / Staff Photo
A small plane used for spraying pesticides awaits takeoff at the Rutland–Southern Vermont Regional Airport before heading to Whiting in an effort to kill mosquitoes carrying Eastern equine encephalitis and West Nile virus on Tuesday evening.
For the second time in five days Tuesday, the state took to the air in its battle against the Eastern equine encephalitis virus.
The flights have turned the fight against the lowly mosquito into a decidedly high-tech affair.
With pilots wearing night-vision goggles and flying computer controlled patterns, onboard computers beam real-time details of the effectiveness back to scientists watching as the computer controls the spray based on preprogrammed graphical information system data.
But, while the cool factor is high in this fight, the human health risk remains.
Mosquitoes in Whiting and Sudbury have tested positive for EEE again this year and seven communities have had positive West Nile virus tests.
EEE and West Nile are potentially fatal mosquito-borne viruses. Two Vermonters died last year from EEE.
On Wednesday, the Vermont Department of Health confirmed the state’s first human case of West Nile virus of 2013 in a Lamoille County resident who has since recovered. A horse was euthanized Aug. 19 after contracting West Nile.
Aerial spraying was ordered in an attempt to prevent additional mosquito-borne illnesses.
The nondescript plane that took off from the Rutland–Southern Vermont Regional Airport on Tuesday evening was actually loaded with enough high-tech navigation and computer-controlled spraying equipment to satisfy any mosquito-killing geek.
The plane is a Beechcraft King Air twin-engine turboprop with spray nozzles on each wing and a pesticide tank in the fuselage.
The technology that delivered the insecticide, however, is where old-school crop duster meets 21st century high-tech.
Cary Giguere, pesticide program management chief of the Agency of Agriculture, Food and Markets, said the state hired Dynamic Aviation out of Virginia.
“It’s all computer controlled,” Giguere said. “It’s one of the reasons we hired this company.”
The state targeted the area for a second application to kill off any mosquitoes in the 10,000-acre — or about 4-square-mile — area that was missed when the first spraying took place Aug. 22.
The mosquitoes that were not yet hatched or that were in a larval stage last week, should have become adults and those were the targets of the second spraying.
“We’re basing the treatment on the life cycle of the mosquitoes,” Giguere said, adding that while it is species and weather dependent, three days is the average life cycle in this area. “There could have been mosquitoes as larvae in the water and we wouldn’t have killed those. With the mosquito treatment we’re only killing active flying mosquitoes.”
With a focal point north of Stickney Road and just west of Route 30 in Whiting, the treatment area pushes into Salisbury and Leicester to the east, Cornwall to the north and Shoreham to the west.
Within that area are places the state doesn’t want to apply pesticide, like organic farms.
“Certified organic farms get buffered,” Giguere said. “We’re giving them a 500 foot buffer.”
By programming the coordinates of what should and shouldn’t be sprayed, the computer controls the nozzles on the planes sprayers turning them on or off at the appropriate times.
The computer is constantly taking into account the temperature, wind speed and direction, humidity and other factors to tailor the delivery to the conditions, and even guides the pilot’s flight plan to deliver the pesticide to the right areas while keeping it off those areas where it shouldn’t be applied.
All the high-tech wizardry, however, takes place out of eyesight.
Tim Schmalz, plant industry section chief for the state Agency of Agriculture Food and Markets, said that while it’s pretty neat, watching it isn’t very exciting.
There are no contrails as the pesticide is sprayed in an extremely fine mist at about 800 feet of altitude, where it settles very slowly toward the ground with the expectation that mosquitoes will fly into it and be killed.
“I think you would be hard pressed to see anything happening if it was in daylight,” Schmalz said. “I think it would be quite dull. I think the most interesting thing about it is how uninteresting it is.”
The plane is equipped with technology that allows it to track the spray as it moves toward the ground and sends real-time data back to state personnel tracking the progress of the application at the airport.
“It’s all managed by GIS,” Giguere said. “We actually watch them in real time. We can watch the spray nozzles turn on and turn off. It’s a pretty high-tech operation.”
Personnel with the agriculture agency place drift cards, which detect pesticide when it hits them, inside and outside of the targeted spray block to see if the aerial applications are on target or not.
“We get a pretty good map of where the treatment occurred,” Giguere said.
Adding to the difficulty level and bringing another layer of technology to the process, all of the applications are done after dark, requiring the pilots to fly using military-grade night vision goggles.
Giguere said the applications have to be done when mosquitoes are most active but after the sun sets.
“We’re not going to let them spray until after dark,” Giguere said. “We want all the bumblebees and butterflies to go to sleep before they get out there to spray.”