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Moth spray starts Tuesday Bacterial pesticide usually has little effect on humans By TONY BOOM ASHLAND - A pesticide to be sprayed by helicopter on 160 acres in hills above Southern Oregon University has an excellent human safety record, according to the Oregon Department of Health and numerous scientific studies. The spray is part of an effort to eradicate gypsy moths and has few known effects on humans or other animals. But the department warns people to stay inside until the mist settles and advises those with impaired immune systems to consider leaving the area. Scientific literature documents few adverse health effects from the pesticide. Oregon's Department of Agriculture will spray between Indiana Street and Glenwood Drive south of Madrone Street in the early morning hours of Tuesday, May 7 and May 17 to get rid of the moths. A 10-acre ground spray effort in the area last year did not eliminate the pests, which can defoliate trees and leave them susceptible to disease. The pesticide, Btk, is a variety of Bacillus thuringiensis (Bt) produced for biological pest control of moths. Bt is a common bacterium that was found in 70 percent of soil samples taken from around the world in one study. Ashland will be sprayed with Foray 48B, a water-based product made by Novo Nordisk that contains 2.1 percent Btk. The bacterium suppresses caterpillars' appetites, slows movements and causes death within days. Bt pesticides are used for food crops, greenhouses, forests and outdoor home applications, according to the National Pesticide Telecommunication Network Web site run by Oregon State University. Btk has been used for more than 25 years in the United States, Canada and New Zealand. "The health division has indicated that Btk has an excellent safety record," said Kathleen Johnson, plant and pest disease programs supervisor for the Oregon Department of Agriculture. "All of the studies made of projects similar to ours indicate there's no significant impact of Btk sprays to people." Johnson was involved in large-scale gypsy moth spraying in Lane County that totaled 225,000 acres in 1985 and 189,000 acres in 1986. An Oregon Health Division study conducted during the spraying found that Btk could neither be ruled in nor ruled out as a source of disease for three people with pre-existing medical conditions in an area with 120,000 people. A study of spraying on British Columbia's Vancouver Island showed no relationship between Foray 48B application and short-term human health effects. British Columbia researchers also were unable to find a single case where Btk caused infection in HIV-positive individuals. Physicians have been unable to link Bt exposure to allergy or asthma problems, according to an article in the Journal of Pesticide Reform. Human volunteers have both ingested and inhaled Bt pesticide for five-day periods. No adverse effects appeared in the volunteers in the study conducted in 1959 and published in the Agricultural Food Chemical journal. Skin and antibody reactions were reported for workers who handled Btk-treated crops in a study published in Environmental Health Perspective in 1999. Manufacturer Novo Nordisk's 1991 material safety data sheet for Foray 48B warns, "repeated exposure via inhalation can result in sensitization and allergic response in hypersensitive individuals." A Novo Nordisk memo says it is possible that someone with developed allergies to a component of Foray 48B or asthma could be affected by exposure to small quantities of the pesticide. Concentrations of airborne Btk were found to be higher in houses than those outdoors five to six hours after spraying, according to a University of British Columbia study. At first the levels were reversed. The initial benefit of remaining indoors during spraying may not persist as outside air moves indoors with normal activities, the study reports. "I don't mind site-specific applications, but when it comes to wide-area spraying I don't like the idea one bit," said City Councilman Cameron Hanson, who cast the lone vote against spraying at the council's Tuesday meeting. "Ground application would be much more acceptable. I'm not against the application of pesticide, but the way it is being applied." Hanson is concerned about possible effects on other animals and plants in the area, even though Btk is formulated to target moths. Spraying has a broad impact for all butterflies and moths, says Paul Runquist, an Ashland environmental advocate for butterflies who provides them to schools. "We are going to affect a few things locally, but the valley's impact is going to be quite negligible," said Runquist. "Most of the butterflies are not that abundant during the (spray period) and that's to their advantage." Reach Ashland bureau reporter Tony Boom at 482-4651, or e-mail [email protected] Mail Tribune Home | Ottaway Newspapers, Inc. | Dow Jones & Co., Inc. | Privacy | Contact Us Copyright � 2001 Mail Tribune, Inc.