Gypsy Moth spray remains controversial

The bacteria used to kill the pest has no proven danger to humans or pets, but skeptics question the state's claims

Gypsy Moth spray remains controversial

Gypsy Moth spray remains controversial

The Washington State Department of Agriculture (WSDA) is taking steps to eradicate gypsy moths, and the methods used are not without some controversy.

 The first treatment in the Graham/Puyallup area happened mid-May, depending on the weather. A low-flying airplane will apply the pesticide, a naturally occurring bacteria called Bacillus thuringiensis kurstaki, using GPS to ensure on-target application. Each subsequent treatment will be approximately three to 14 days after the initial aerial spray. WSDA expects to complete all applications by the end of May.

Claude Ginsburg is the director of No Spray Zone, a community based citizen group dedicated to ecologically sound pest management practices that do not compromise public health.

“The [state] claims rigorous science behind this, but some of the science is a little funny and questionable,” he said.

The state said there is no risk from the treatment, and that not acting quickly and effectively is a nonstarter.

Karla Salp, public engagement specialist for the WSDA, said the gypsy moths are incredibly destructive.

“It’s highly invasive in the United States,” she said. “Back east where they were originally introduced, one third of Massachusetts’ entire state was defoliated as a result of these gypsy moth caterpillars. The year prior in New England, the damage was so widespread it could be seen from space.”

WSDA is advising residents in or near the treatment areas to visit and sign up for e-mail, text or robo call alerts issued the day before any application takes place because of the effect the weather can have on the gypsy moth treatments. Changes in scheduled treatments will also be shared via these notification systems. WSDA will use its Twitter account, @WSDAgov, to provide real-time information during operations as well.

Btk is not considered harmful to humans, pets, birds, fish or bees. Btk is found naturally in the environment. Although the risk is low, the Washington State Department of Health says that people who wish to minimize their exposure can remain indoors during spraying and for 30 minutes afterwards as a precaution. The product washes off with soap and water.

Btk is sticky when applied, to better adhere to foliage. Residents in the treatment areas may choose to cover cars parked outside and bring in toys, etc.

Salp said the moths have potential to do widespread damage, both for flora and as a pest to people. She explained many people are allergic to the caterpillar hairs and that the pests eat so many leaves and exist in such large swarms that it may sound like it’s raining outside, when it’s actually caterpillar feces dropping from the trees.

Ginsburg said there were other ways to handle the pests without delving into what he believes could be harmful pesticides.

“There’s another way to use the pheromone in the traps where there’s a technology where you can put that in tiny little plastic beads and scatter those beads from a helicopter and it makes a cloud of pheromone for a month or two, which can completely confuse the male moths,” he said. “Humans can’t smell pheromones, only moths can smell it. It’s less likely to be toxic, but I’m not a PhD chemist and nobody’s done the research. Pheromone beads are quite expensive.”

Another method to get rid of gypsy moths, Ginsburg said, is mass trapping, which involves putting up a large number of traps that would kill all the male moths before they can find a female, an expensive albeit effective method.

On February 20, 2018, Graham resident Raymond Cool attended the Gypsy Moth Open House hosted by the Washington State Department of Agriculture.

For the half hour that he was at the meeting, it was about the gypsy moth program in Graham. The spraying takes place in south Puyallup and a section of Spanaway as well as in South Hill.

“I thought it was disingenuous to refer to Graham spraying in their notifications that they sent out for people in the local spray zone and not people outside of the spray zone,” Cool said. “People will get it and think it represents Graham and not pay attention to it because they live in Spanaway or South Hill. I see that as an intentional deception to meet legal requirements, by leaving every means of deception and that it can go to as few people as possible who read the notification and show up at the meetings.”

For more information about the gypsy moth program, visit: to learn more or call the WSDA toll-free hotline at 1-800-443-6684.


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