Managing Beetles to Preserve Elm Trees

 

American Elm removal Commonwealth Avenue Mall June 17, 2014
A Commonwealth Avenue Mall Centenarian is removed due to Dutch elm disease (2014)

The Friends has been funding the expert care of trees since 1970 as part of our mission to preserve and enhance the Boston Common, Public Garden, and Commonwealth Avenue Mall. This work would not be possible without the financial support of our Members. We are always delighted when Members express a genuine interest in learning more about the details of the work we do. We noticed an increase in questions about tree care coming in over the past few months, and in particular inquiries about our work related to the elm bark beetle and Dutch elm disease, which seem to have been sparked by our Members Reception presentation (Digging In: Beyond the Roots of Urban Tree Care). We asked our contractor Christine Helie to explain some of the work she does for us. She is an entomologist and field scientist who works with her husband Normand at The Growing Tree.  Chris is directly involved in developing an Integrated Pest Management program to preserve the mature and young elm trees in our parks. Here is what she had to say:

 

Among the trees in the Public Garden, on the Boston Common and on Commonwealth Avenue, is a unique collection of elm trees. This valuable assortment of European, American and Asian elms are susceptible to Dutch elm disease (DED). This disease is caused by a fungus that compromises the conductive tissue of the tree and eventually kills it. The primary vector of the fungus is the European elm bark beetle. Through its breeding and feeding behavior, this bark beetle transfers DED from diseased trees to healthy trees.

In 2012, with the support of Greg Mosman, Tree Warden of the Boston Parks & Recreation Department and on behalf of the Friends and its tree care program, a monitoring and management system for this insect was designed as part of a new elm tree preservation program for the mature and young elm trees in the three parks. The manner in which insects are monitored and managed can vary depending on the habitat in which they exist. For our purposes, a three sided box of plywood, painted green was built to house an 18”x25” sticky trap with a pheromone lure attached in the center.

Pheromones are chemicals produced by an organism that elicit a response from another organism. They are used by insects or animals to communicate with individuals of the same species. Depending on the type of activity, different pheromones will be used to relay a message.

For example, ants use a trail pheromone to mark a path leading to food that other ants in the colony can find and follow. However, when encountering a dangerous situation they use an alarm pheromone to warn their nest mates. The pheromones used in our beetle traps signal to both male and female elm bark beetles that this is a great spot for breeding and laying eggs.

There are over 24 traps in use throughout the parks. From the beginning, our goal was to

Beetle counter, PG, May 23, 2014, EAJ
beetle trap

make them easy to access but discreet. Rather than placing unsightly posts throughout the parks, we decided to install our traps on trees at least 150 feet away from any elm trees.

Because the bark beetle is attracted to elm trees weakened by stress, one of the components in the pheromone mimics volatiles released by a stressed elm tree. As a result, the trees that we chose to place our traps on became substitute elms, luring the elm bark beetles away from the elm trees.

Pheromones are effective at very low concentrations and insect specific. This fact becomes evident when you compare some of the trees with traps to an actual elm tree. The vase shaped elm tree with upright branching is quite different from the pyramidal shaped Norway spruce with drooping branchlets.

The elm has a broad leaf with a serrated edge, whereas the spruce has needle-like foliage. The bark of an American elm tree has deep crevices that form diamond-shaped furrows, while the bark of a Norway spruce tree has thick round scales.

Regardless of these features though, the Norway spruce in the Public Garden has consistently captured high numbers of the European elm bark beetle on its trap.

Below are images showing the physical differences between Elm trees (top photos) and Norway Spruce trees(bottom).

Bark beetles appear to use different methods when locating a proper host tree. By crawling on the bark, they can sense the texture and determine whether the tree is susceptible to attack. Dispersing beetles are also guided by odors from weakened trees. From what we have observed in our program, it seems apparent that when the beetles land on a potential host, one of our stand-in elms, the odors detected override the physical clues they pick up from the tree. As a result the beetles continue to search for the source of the pheromones until they are caught on the trap or die trying to find the “elm.”

These traps have also allowed us to monitor the location, concentration, and pattern of movements of this disease host, helping to indicate the optimal times to treat, prune and, in some cases, remove a diseased tree.

Since their implementation, the elm bark beetle traps have become important tools in our fight against Dutch elm disease. The twenty four traps in use throughout the parks and surrounding areas are installed on thirteen different tree species. While these trees may be Oaks, Locusts, Maples, Lindens, or even a Norway spruce, they actually serve as substitute elms and are important allies in the preservation of our real elm tree population.

Landolt, Peter J. “Sex Attractant and Aggregation Pheromones of Male Phytophagous Insects.” American Entomologist Spring 1997 12-22. Print.

Message from Board Chair Anne Brooke

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Anne Brooke thanking Members and supporters at the 2015 Summer Party (Photo: Piece Harman)

 

Dear Friends,

It has been a wonderful year for the Friends and our three treasured greenspaces. Our work in 2015 has brought so many plans and projects to life that have improved the Boston Common, Public Garden, and Commonwealth Avenue Mall. One might say that how it all comes together is magical, and sometimes it feels that way, but it is actually the efforts and generous support of many individuals that make it possible.

Thank you to my fellow Board members, our dedicated Members, volunteers, donors, and our talented Executive Director and staff. Each of you makes a difference in all that you do.

You are these parks’ greatest supporters and advocate voices. Because of your contributions, more than $1 million was invested in parks care and programs in 2015, the restoration of the Garden’s George Robert White Memorial fountain will break ground in the spring of 2016, 10 trees and three benches are newly sponsored, and so much more.

We kindly ask that you continue your stewardship by renewing your Membership before the end of the year, inviting friends to join, and delighting someone with a gift of Membership.

We look forward to working together with you in the new year to continue raising the level of excellence in these three greenspaces we care for in partnership with the City. As you know, it takes a great deal of work, advocacy, and money to maintain and improve them; and sometimes a little magic, too. You are the magic that makes it happen and we can’t do it without you.

Wishing you a happy and safe holiday season,

Anne Brooke

Chair, Friends of the Public Garden

Summer Party Raises Roof and Funds for Parks

We were delighted to be joined by 170 Friends at the Rooftop of the Taj Hotel on July 22 for our second annual Summer Party. The event doubled in size from the the previous year and sold out nearly one month earlier. Thank you to our generous event sponsor First Republic Bank, and to old Friends and new who stepped out to celebrate and support the three parks we care for in partnership with the City. Read about the evening in the Boston Herald  and visit our Facebook album to view more photos.

Photos: Pierce Harman

Spend an Majestic Morning with Puppets on the Common

FOPG Puppets on the Common, August 22, 2014 by Elizabeth Jordan (5)

The Friends of the Public Garden is pleased to present:

Puppets on the Common
“The Enchanted Castle and the Royal Park”
Boston Common, Parkman Bandstand
Wednesday, August 19, 2015
10:30 a.m.
Children are welcome to join the Friends and Rosalita’s Puppets for a majestic morning of entertainment featuring Fairy Godmother Glitter and Princess Crystal who will be accompanied by their pals Dragon, Wizard, Unicorn and several fairies.

The M. Holt Massey Charitable Trust is sponsoring this show.

It’s Hot, Humid, and the Public Garden Tropical Plants Love it!

This summer has been hot and very humid, one might even say tropical.The tropical plants in the Public Garden fit right in this year!

IMG_2451 Tropical plants have been present in the Public Garden for most of its history. According to the book, the Public Garden Boston published by the Friends in 2000, they were first planted by William Doogue in the late 1800’s. The palms and other plantings were stored in the greenhouses and brought out to be placed in the Victorian-style garden. Doogue’s horticultural displays stayed true to the Victorian style, however not everyone loved the non-native species. Many considered it odd to have such plants in the Boston Public Garden. However, these plants appeared year after year to continue the tradition and to further educate people on plants from around the world. IMG_2442 Today, the tropical plants continue to educate and honor a tradition started by Doogue over a century ago. A new executive assistant in the parks department, Josh Altidor, has designed beds that attest and expand this practice. The Boston Globe recently featured Josh in a story about this year’s plantings. IMG_2444 IMG_2449 IMG_2447

Meet the Friends: Bob Mulcahy

BobMulcahyFOPG Bob Mulcahy has been working as the Friends Project Manager for the past four years. He came to know the organization through his work as a project manager in the Boston Parks and Recreation Department, where he was employed for five years. As the Friends Project Manager, Bob oversees the direct care of the three parks, including tree pruning, planting, and disease control; turf care; and the organization’s various capital projects such as renovations at Brewer Fountain Plaza and the Boylston Street border of the Garden. His experience working with the City and his love for the parks give Bob a unique perspective on these greenspaces and the people who are involved in their care. Bob works hard to maintain and improve the beautiful, historic green spaces that are so beloved by the city, especially by Bob himself. “These three parks are a direct link to the history of the country and the residents that move through the downtown area,” he says. “To fight for them and beautify them is gratifying and motivating. I’m proud to be part of an organization that is committed to that.” There are many dedicated individuals who work in a variety of stewardship roles to keep the Boston Common, Public Garden, and Commonwealth Avenue Mall in their best condition for all to enjoy. The “Meet the Friends” series was created to showcase these passionate individuals and their significant contributions.

Boston Common Frog Pond Wading Pool Opening July 1

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Boston Parks Commissioner Chris Cook and The Skating Club of Boston president Joe Blount will welcome children and guests to kick off the 2015 summer season as the Boston Common Frog Pond reopens on Wednesday, July 1. The day will include a fun and exciting celebration at 11 a.m. followed by the opening of the wading pool.
“Boston’s youngest residents are ready to cool off from the heat as the Frog Pond wading pool opens for the season,” said Mayor Martin J. Walsh. “I hope all of our residents are able to enjoy the Common this summer. This is a great place for families to relax with a carousel, food concessions, and the Swan Boats all within walking distance.”
In addition to activities from 11 a.m. to 1 p.m., information regarding upcoming summer programs offered by the City of Boston and the Boston Public Health Commission will be available to families and residents and tasty treats will be provided by in-kind sponsors HP Hood LLC, Cabot Cheese. DAVIDsTEA, and Polar Beverages.
The celebration will feature a special visit from official mascot Frog Pond Freddie, entertainment, face painting, books courtesy of ReadBoston, and giveaways from Mix 104.1 FM. In addition, children of all ages are eligible to enter a summer raffle.

The Frog Pond spray pool will be open for wading daily from 11 a.m. to 6 p.m. until Labor Day. Visit http://www.bostonfrogpond.com for more information.