Sustaining a thriving lobster fishery through science and community.
Harpswell Anchor, February / March 2002
Browntail wagging the dog?
Budget Committee backs Dimilin spraying for the browntail moth and sends the issue to selectmen.
By Molly Laird
As Harpswell weathers another warm winter, browntail moth caterpillars lurk sheltered inside their webs. These mild winters have strengthened the browntail population all along Casco Bay. Come summer, the caterpillars will emerge and release their toxic hairs, creating an itchy poison ivy-like rash and stressing respiratory systems among some people.
At the Jan. 24 selectmen's meeting, Maine Forest Service entomologist Dick Bradbury made his formal recommendation for spraying the browntail caterpillars this May. "I'm the messenger,"he said. "Don't shootthe messenger."
Surveying the Harpswell trees, Bradbury forecast 2002 as a bumper crop for the browntails and has recommended aerial spraying of the pesticide Dimilin over 1,650 acres. The shoreline will not be sprayed. Dimilin, manufactured by Uniroyal, is known to be toxic to marine invertebrates as well as to the persistent browntails.
Dimilin interferes with the caterpillar's ability to molt. 'They actually blow themselves up not a good way to go," explained Bradbury. "Unfortunately, a lot of marine animals are very related to browntail moths."
Bradbury gave a frank assessment of risks faced by the Dimilin application. Most notably to Harpswell residents is the effect the pesticide has on lobsters. Dimilin's warning label begins: "This pesticide is extremely toxic to crab, shrimp and other aquatic invertebrates."
The Environmental Protection Agency bans the use of Dimilin within 150 feet of the high water mark. The substance kills for 72 hours. It is a stable compound and will last in the soil for 14 days. In cold water, however, the substance will last for weeks or possibly months. Uniroyal also cautions: "Drift or runoff treated areas may be hazardous to aquatic organisms in neighboring areas."
The key for safety seems to be keeping it out of the water. By spraying in early May, said Bradbury, the insecticide will miss a lot of insects still in their larval stage. It is a low risk for mammals, and "it's the only game in town we've got for now," he explained.
When the state sprays insecticide, workers place spray-sensitive cards to monitor any chemical drift. "In all our card tests," said Bradbury, "we were never off by more than 90 feet."
"We monitor pretty tightly. Certainly the possibility exists you could get out of that range. Within the last eight years we had one case that below the high water mark we had a trace. We try to spray at high water. If we do get it in the water, a 9-foot shift in water will dilute it, spread it out pretty rapidly.
The Budget Committee made a recommendation to spray for browntail moth, providing that "selectmen satisfy themselves regarding the effects of Dimilin and consider a combination of air and ground application." The committee recommended "no less than $45,000" and that the warrant should allow the voters to increase the amount of money appropriated.
There was no town spraying in 2001. In 1999 and 2000, Harpswell sprayed the pesticide Confirm up to the water's edge, as recommended by the state. Confirm was used because of concerns about the risks of Dimilin.
Confirm was promoted as a safe agent with little effect on marine animals.
"That's bullshit," said one lobsterman angrily. "There were a lot of weak lobsters. I had a hard time keeping them alive. I was hauling up dead lobster and I never saw it before. The spraying made them real weak."
Another lobsterman said, "Three years ago I was finding dead shedders (soft shelled lobsters) in the traps. It's clear they're spraying it and testing it at the same time."
Confirm "gave a marginal insect kill," said Bradbury. "It was touted as safe to use right up to the water, but in New York they found it retards growth in oysters."
"I'm not one to suggest a risk," he said of his recommendation of Dimilin. "We know it's harmful to invertebrates, so with a 150-foot buffer zone, it is a minimal threat."
In its "vision statement" the Department of Marine Resources states it "provides leadership in marine policy, the management of marine resources, the development of sustainable marine resource-based business and the protection of the marine environment."
When asked about the widespread reports of weak and dying lobsters following spraying, DMR Director of Resource Management Linda Mercer reported, "We don't have any evidence of that."
In 1999 and 2000, the DMR conducted limited testing on the effects of pesticide spraying on lobsters. Sublegal lobsters were placed in modified traps in the bay before spraying. They were collected a week later and monitored at Bigelow Laboratory in Boothbay Harbor. The test lobsters in a way deemed healthy and it was concluded that the spraying had no ill effect on the lobster population.
"Because the lobster resource is very valuable," Mercer said, concern is warranted. Now that the state is recommending a pesticide known to be harmful to these marine resources, Mercer says the state is trying to restrict areas of pesticide use. Advocating a conservative approach, DMR recommends towns "restrict spraying to the worst areas."
While DMR plans to "do some monitoring to make sure lobsters aren't affected" by the spraying, Mercer conceded, "the browntail moth is a serious health hazard."
Will spraying hurt fisheries?
DMR's chief lobster biologist Carl Wilson found himself scrambling for information as towns along Casco Bay considered the browntail spray issue.
"Weak lobsters showed up in September in a larger area than sprayed," the biologist pointed out. "It's easy to link spraying with the lobster die-off in Long Island Sound (NewYork), but those accusations haven't borne out.
Of the sea sampling program he runs, placing DMR workers on lobster boats recording the contents of every trap hauled in a day, Wilson said, "We do pay attention to weak and dead lobsters," but the program is mainly to "track distribution and abundance of lobsters and fishermen."
Wilson plans to redesign control traps to look at the impact of spraying on juvenile lobsters.
"Along the shore, the little juveniles in seaweed will be much more susceptible," said lobsterman David Wessel. As a representative to the Lobster Conservation Management Team, Wessel has been working with scientists, government officials, and other fishermen to get the lobster industry in compliance with federal guidelines against overfishing. Along with most fishermen, Wessel has been a vocal opponent of spraying. The risk to the marine resources seems way too high to him.
"There is a lot of concern about the clams as well," said Wessel. "Clam flats are very susceptible to runoff."
Over at the Lobster Conservancy, biologist Diane Cowan laments the lack of data. If scientists don't know the size of the healthy lobster population, they won't be able to tell if there is sudden drop in it.
"It's true that the data are poor. The observations of fishermen are not seen," said the founder of the Lobster Conservancy and its senior scientist. "Because there isn't a census, there's no way to make that correlation"
What is clear is the effect of Dimilin on lobsters. It interferes with the production of its shell. "It is absolutely known that it is toxic to crustaceans. The effects are not immediate but it is more likely to die when it molts. None of the experiments have followed it through," said Cowan.
Young juvenile lobsters molt several times a year. Cowan pioneered the ongoing census of these tiny lobsters in 1993. In 1999 and 2000 she saw numbers that echo the reports of area lobstermen.
"They were low years, but I can't say why," she said "There are so many factors that affect this. What we need are controlled experiments and we haven't done them."
Of spraying pesticides in general, Cowan cautioned, "You just strengthen them (the insect you're trying to kill). You produce a more resistant breed."
The browntail moth infestations tend to run in 10 year cycles. Eventually the moth population will drop.
Browntail moth infestations also occur in Cape Cod, Mass. They don't spray down there, though. "The National Seashore people are pretty warm and fuzzy," said entomologist Bradbury. "All they do is a limited amount of clipping."
The Forestry Service plans to experiment with a natural virus against the browntails. Possibly it will be tested on state land by Clark's Cove in Harpswell in an area too close to the water for spraying.
"We're always trying to find something more benign than applying Dimilin," said Bradbury, who advocates a range of methods for browntail eradication.
"There's a number of places where people can help themselves," said the entomologist. "Clipping is an ideal way to go." September to late March is the best time to clip the browntail tents from accessible bushes and trees. Sometimes removing decrepit fruit trees is the best solution. Once clipped, the webs need to be burned or put in soapy water. A couple good squirts of dishwashing soap one ounce per gallon will break down the webs and drown the bugs.
Away from the water, tall red oak trees are the browntails' primary hosts. These pole-sized trees grow 30 75 feet high. Even with a bucket truck, said Bradbury, arborists can't effectively clip and retrieve webs.
Homeowners can opt out
Since browntail moth arrived in New England in 1897, it has been especially prevalent in the islands of Casco Bay. Harpswell resident Chris Coffin advocates more aggressive spraying. As the caterpillars are strongest on uninhabited islands, he suggested targeting these areas.
"Hit these outer islands," he argued. "It will give us some relief."
Recently, residents of Birch Island wrote a plea for spraying out on the island. Several people had suffered terrible effects from the caterpillars last summer. If the town wasn't going to spray, they said, they would have to spray it themselves.
"If spraying isn't done in an organized way," said John Sowles of the DMR, "homeowners go out on their own."
"It's scary to me when homeowners attempt pesticide applications. It takes industrial equipment," warned Bradbury. While Dimilin isn't available to consumers, anyone can buy a pesticide called Sevin, which, according to Bradbury, "will kill lobsters (like) gangbusters. If you were trying to control lobsters that would my choice."
One ill-informed home owner applied 40 acres worth of pesticides to her 1/4-acre yard. Another used 48 cans of Raid to attempt to control pests in his yard. "People get desperate and do some crazy things," said Bradbury.
"The nice thing about municipal spraying is it does a uniform application with a minimum of pesticides," the entomologist continued. Sprayers use one to two ounces of pesticide per acre. "If you can take care of these problems then homeowners won't resort to unacceptable methods of control. The pesticide exposure rate is a great deal less than if your neighbor is throwing Sevin all around." When the state sprays, the Board of Pesticides Control places inspectors on site, inspecting aircraft or ground applications. Commercial sprayers "across the board, do a good job," said Bradbury.
However, at the Jan. 30 meeting of the Zone F Lobster Council, a lobster man from Chebeague Island said of last year's spraying, "All the lobstermen were against it and they did it anyway." After watching the plane flying over the island, he expressed disbelief that they had any control over where they were spraying. He said pesticide drift is a major concern.
There is a map of the recommended spray zone in the lobby of the town offices. The Forest Service survey for moths determined the spray area, which was based on large numbers of caterpillars and large numbers of homes.
If spraying is approved at town meeting, municipal officials will contact everyone within the spray zone. Homeowners have 30 days to opt out if they do not want their property sprayed.
Bradbury predicted aerial spraying would be extremely effective at getting at the browntail moth population. While $45,000 was recommended by the Budget Committee, Bradbury estimated the town can probably do it for less if it's an aerial application.
Bradbury maintained that the only big risk in spraying is if a plane crashed into the water.
Bradbury urged voters to make an informed decision, weighing all the risks and benefits. "If they don't want to spray, that's fine with me," said Bradbury, who will be presenting at the March 9 meeting. "I get paid the same whether we spray or not."
The Lobster Conservancy's Diane Cowan also plans to present at town meeting. "I believe what the lobstermen see in their traps," said Cowan. "I also know it's a hard thing to get at." When be the cost of spraying is considered, she said she hopes everyone looks at more than just the dollars involved.