Support the Timberjay by making a donation.

Serving Northern St. Louis County, Minnesota

Ely declares war on the gypsy moth

Aerial spraying will commence in June

Keith Vandervort
Posted 1/19/16

ELY – Ely is on the front lines of the gypsy moth’s inevitable spread eastward across the northern United States.

The city has declared war on the leaf-eating insect and the Minnesota …

This item is available in full to subscribers.

Please log in to continue

Log in

Ely declares war on the gypsy moth

Aerial spraying will commence in June


ELY – Ely is on the front lines of the gypsy moth’s inevitable spread eastward across the northern United States.

The city has declared war on the leaf-eating insect and the Minnesota Department of Agriculture is proposing to treat an area on the southeast side of the city next summer in an effort to slow the march of the invasive species across the state.

According to Kimberly Thielen Cremers, pest mitigation and regulatory response unit supervisor for the state agency, the gypsy moth has already established a toehold in Lake and Cook Counties.

Cremers spoke to members of the Ely City Council Tuesday night to describe the plan of attack which will commence sometime in June in an area roughly bordered by 2nd Avenue on the west, Camp Street on the north, 15th Avenue on the east, and Look Out Ridge Road south of the city in the town of Morse.

Aircraft will fly some 50-feet above the treetops and spray an insecticide in the early mornings sometime in June. She said two treatments about a week apart, will likely be needed, to kill the gypsy moth larvae.

Cremers met with city staff last week to brief them on the seriousness of the insect’s infestation in Ely and made the public presentation to describe the insect and what it can do to the trees and foliage in the city if left unchecked.

The gypsy moth is a non-native or invasive species that was introduced on the east coast of the United States from Europe in the 1880s in an attempt to breed a hardier silk worm. Instead, it escaped and took to the trees. “It truly is an experiment gone wrong,” she said

“It was probably the most destructive tree pest in the U.S.,” Cremers said, “until the emerald ash borer was discovered in Michigan in the early 2000s.”

She described the biology life stages of the insect and how that is used to survey and propose management steps. “In this part of northern Minnesota the life stage is about four weeks delayed as compared to what it would be in the southeast part of the state,” she said. “We will see larval emergence in early June, but the most important stage is the egg-mass stage, when the gypsy moth can hitchhike and transport across an area, typically in September and through the winter to the following June.”

Cremers said each gypsy moth egg mass will contain 500 to 1,000 viable caterpillars. “It only takes a couple of these egg masses on logs or camping equipment to become established in a new area,” she said.

The gypsy moth will go through five or six growth periods during its life cycle. They start out very small and will grow into a large caterpillar that is very distinctive with five pairs of red dots and six pairs of blue dots on their back. “Those dots are key characteristics in identifying the larva,” Cremers said. Adult caterpillars will be in development in late July in the Ely area.

The larva then proceeds into the cocoon stage and emerges as an adult moth. “During this stage is how we monitor for population growth and their spread across an area,” she said. “That’s when you will see those tent-shaped traps, which are our detection tool.” Only the male moth is capable of flight.

Why be concerned?

The gypsy moth is a tree defoliator and can devastate whole urban areas or forests. “Caterpillars will consume a nine-foot square of foliage in its lifetime. You times that from 500 to 1,000 caterpillars (from just one egg mass) and it won’t take long to have a whole tree defoliated,” she said.

On average, defoliation across the U.S. was 1.2 million acres from 2006 to 2010. “Defoliation causes stress on trees that eventually leads to tree mortality,” she said.

Cremers noted that humans could have allergic reactions to the gypsy moth. “And they are completely messy and impact areas with high tourism. A large outbreak can lead to leaf parts and moth droppings literally falling out of the trees, similar to a forest tent caterpillar or army worm outbreak.”

The gypsy moth eats from a menu of more than 300 species of trees and shrubs. “Oaks, aspen, willow and birch are some of their preferred leaves and we have a very high component of both aspen and birch up north,” she said.

The gypsy moth naturally migrates with the wind across an area at about one mile per year. With the help of human interaction, that rate of movement can average about 15 miles per year.

Currently, the gypsy moth is only established in about a third of the U.S., she said. “We are still protecting about two-thirds of the U.S. in which it will eventually become established. It will eventually be established within the state of Minnesota in forests and urban area,” she said.

The battle begins

In 2015, as many as 1,051 gypsy moths were detected in Minnesota, including 61 in St. Louis County and 20 in the city of Ely.

The survey area around Ely has been ongoing for a couple of years. “Just because you might see a moth, doesn’t mean you have an established population,” she said. “We won’t treat an area with just a single moth. You have to have a pattern of introduction.”

Last year in Ely, multiple gypsy moth life stage evidence was found. “We now know that there is a reproducing population established here,” she said. “Ely is actually the furthest west of the spread of the gypsy moth and we feel an eradication in this area can hold back that spread.”

The Department of Agriculture is proposing a 565-acre eradication effort on the southeast portion of the city.

An environmental assessment will be conducted to determine the most appropriate product to use in the eradication process, including input from the U.S. Fish and Wildlife Service and the Department of Natural Resources.

A biological insecticide will be used, according to Cremers, which is actually a naturally occurring bacterium and only kills caterpillars. “BtK is a stomach poison and must be ingested by the caterpillars, she said. “It breaks down pretty quickly in sunlight, more than 50-percent of it is broken down after only four hours after application. She said the insecticide has been available for more than 40 years and is used in organic farming.

“In rare cases, some people with severe food allergies can respond to BtK,” she said.

“Symptoms can be amplified in some people knowing that aircraft are spraying and anxiety levels are raised.”

Eradication efforts in Ely will begin in June during the early life stage of the caterpillar. “We usually apply in the very early morning hours, depending on wind and humidity. There will be two treatments about seven to 10 days apart,” she said.

Low flying aircraft, either airplanes or helicopters, will fly some 50 feet above the treetops.

All residents in the treatment area will be notified by mail of the upcoming treatment schedule.

An open house on the proposed insect treatment will be held on Monday, Feb. 22 in the Ely City Hall Council Chambers.

Other business,

In other business, the council took the following action:

• Accepted a proposal from John Ott to purchase the old Ford garage property for $5,000 and directed staff to develop a purchase agreement;

• Approved the following committee appointments, EUC Commission, Warren Nikkola and Kurt Soderberg, Planning and Zoning Committee, Tim Riley, Police Commission, Anthony Colarich, and Heritage Preservation Commission, Phil Hyde;

• OK’d reposting for volunteers to fill vacant seats on the Commission, Library Board, Planning and Zoning Commission and Projects Committee

• Awarded the 2016 Ely legal publication bid to the Ely Echo;

• Listened to a proposal from Ely Event Coordinator Wendy Lindsay to expand musical entertainment at the Ely Marathon event in September;

•Appointed Heidi Omerza to the position of acting mayor, replacing Jerome Debeltz;

• Passed a resolution supporting the Ely Community Health Center.


No comments on this story | Please log in to comment by clicking here
Please log in or register to add your comment