Spraying of Btk begins for gypsy moth infestation
SHADY COVE — With the sound of a helicopter's rotors beating against the early morning air Thursday, an aerial attack on the city's potentially devastating gypsy moth infestation was under way.
Originally scheduled to begin just after sunrise, below freezing temperatures and frost on foliage delayed the helicopter's takeoff until 8:10 a.m.
As the sun finally managed to climb above the surrounding mountains, temperatures rose from a morning low of 29 degrees to 37 at takeoff. Winds were light and a thin fog that had hidden the hillsides drifted away, leaving a sunny sky.
With two spray nozzles on each side, the Bell Model 206 JetRanger helicopter began spraying the kurstaki variant of the biological pesticide bacillus thuringiensis (Btk) over 336 infected acres in the southern part of town.
A team from the state's Insect Pest Prevention and Management Office, a unit within the Oregon Department of Agriculture, was on hand to observe the first of three scheduled applications of the pesticide.
"We want to be sure we do this exactly right," said Dr. Barry Bai, entomologist for the state. "We've calibrated our sprayers to make sure we spray just where we want to, and with just the right amount of material."
The helicopter crisscrossed the target area, which is generally south and east of the Rogue River, and west of Highway 62. Four misty streams of spray trailed behind before quickly disappearing as they fell toward earth.
"We only use one-half gallon of Btk per acre," said Bai.
The foliage must be sprayed during the moth's feeding stage as a caterpillar, which lasts from when eggs begin hatching in late March until roughly the end of June.
Btk kills the moths by suppressing appetite and restricting their movement, and though it is deadly to the insect pest, officials said it's safe for humans.
"The commercial Btk product being used in Shady Cove has been certified as an organic formulation," said Bruce Pokarney, ODA director of communications. "It has been used routinely in other gypsy moth eradication projects in Oregon since 1984 and it has an excellent safety record."
Jackson County last saw the helicopter in 2001 when 160 acres in Ashland got an aerial dose of Btk.
When the helicopter took to the sky for calibration of equipment and reconnaissance of the target area Wednesday afternoon, frightened citizens began calling the local fire station.
"We had five or six calls," said Fire Chief Bob Millerof Jackson County Fire District No. 4, who had come to the staging area at the Shady Cove airport. "They were scared and said they were sure some kind of colored spray was coming out the back of the helicopter."
Thursday's flight had already been delayed more than a week because of persistent rain in the area.
Weather is important because Btk must have time to dry on foliage, and once applied requires at least six hours without rain. Temperatures must be no lower than 35-38 degrees and winds must be less than 10 mph.
Shady Cove resident Josh Curphey said he liked "watching the whole thing. It sure didn't bother me."
Bai said traps would be set this month and if they turn up empty in late fall, he'll know the project was a success.
"I hope we don't have to come back," said Bai. "Our philosophy is early detection, rapid response and get rid of it with a minimal disturbance to people."
Two additional sprayings are scheduled for Thursday and May 20. Complete spraying schedule information and updates are available toll free at 1-800-525-0137.
Bill Miller is a freelance writer living in Shady Cove. Reach him at firstname.lastname@example.org.