From the Director's Desk: Update on Oak Wilt and Landis

By Fred Breglia

Oaks are our lega­cy here at the Lan­dis Arbore­tum, what with the land orig­i­nal­ly known as Oak Nose Farm” after the 500-year-old Great Oak” that once stood over­look­ing the Schoharie Val­ley. Oaks are a big part of our func­tion­ing ecosys­tem, which includes plants, fun­gi, and wildlife. When the approach of oak wilt was report­ed, we stood by hop­ing it would not reach the Arbore­tum, and so far, so good. That being said, oak wilt has been iden­ti­fied in neigh­bor­ing Sch­enec­tady County.

Bretziella fagacearu
Bret­ziel­la fagacearu 

Oak wilt is a sys­temic, lethal dis­ease caused by the fun­gus Bret­ziel­la fagacearu (pre­vi­ous­ly known as Cer­a­to­cys­tis fagacearum). The fun­gus is spread via root grafts and bee­tles feed­ing on sap at open wounds or on the leaves of healthy trees. Once inside the tree, the fun­gus begins to repli­cate, even­tu­al­ly pre­vent­ing the uptake and move­ment of water. Symp­toms of the dis­ease first appear near the top of the canopy. The out­side of the leaves turn bronze, brown, or dull green, usu­al­ly start­ing at the top of the leaf, while the base of the leaf remains green. Some leaves curl and begin to drop soon after symp­toms appear.

It is more like­ly to affect red oak than white oak. An infect­ed red oak typ­i­cal­ly dies with­in two months, while a white oak can live with the dis­ease for sev­er­al years. If infect­ed, a tree will begin to show symp­toms in mid-summer.

In the past, pre­ven­ta­tive mea­sures includ­ed trench­ing between tree roots, prun­ing only dur­ing hard win­ter, and remov­ing dis­eased trees. Today, focus­ing on reduc­ing mono­cul­ture plant­i­ngs, restor­ing soils, and apply­ing fungi­cides in urban envi­ron­ments are proven to be more effec­tive. It is impor­tant to note that there are ways to con­trol” the dis­ease rather than just con­tain” it. Con­tain­ing it means to cre­ate a bar­ri­er and hope it doesn’t spread. Con­trol­ling the dis­ease takes more effort and involves going with­in the bar­ri­er to remove the oaks, allow­ing native species to regrow. In essence, you woule remove all oaks, espe­cial­ly in a mono­cul­ture set­ting.

Oak wilt could impact Landis. 

At Lan­dis, we have sev­er­al species of trees and plants mixed in with our oak forests, which would prove help­ful in mit­i­gat­ing the spread of the dis­ease should it occur. While our his­toric oak col­lec­tion is at risk as the roots make con­tact, they are also mature and strong, which might help them sur­vive. Sad­ly, if oak wilt were to occur at Lan­dis, in essence, we would remove all oaks from our prop­er­ty in order to pre­vent the spread of the dis­ease to oth­er locations.

There is hope, how­ev­er. Oak wilt was recent­ly found in South Bris­tol, NY (Ontario Coun­ty). After removal of infect­ed trees and root trench­ing efforts to pre­vent spread­ing, the dis­ease site is now receiv­ing a clean bill of health. Work­ing togeth­er, the Depart­ment of Envi­ron­men­tal Con­ser­va­tion and the landown­er were able to erad­i­cate the dis­ease and pre­vent neigh­bor­ing forests from being destroyed as well.

We will con­tin­ue to mon­i­tor the sit­u­a­tion, con­tin­u­al­ly check­ing the health of our oaks. While we hope no action will be nec­es­sary, we also are com­mit­ted to pre­serv­ing the greater for­est envi­ron­ment, both inside and out­side the Arbore­tum boundaries.


Summer 2019

Volume 37 , Number 2

Share this

The Latest from Landis

Aug 06, 2022

Landis Forest 5K - August 6, 2022

A record turnout! Click here to view all the great photos from this event, and... read more

Jun 10, 2022 | Anne Donnelly

Don't Overlook Your Reciprocal Admissions Privilege

A sometimes overlooked benefit of your Landis Arboretum membership is the American Horticultural Society Reciprocal... read more

May 29, 2022

Scenes From the Spring Plant Sale

Thanks to our many wonderful volunteers, plant consignors, vendors, and customers, the Landis Signature Spring... read more

May 28, 2022 | Fred Breglia, Executive Director

From the Director’s Desk: Q&A, Part III

In this last Q&A session, I am focusing on leaf color change during the... read more

May 28, 2022 | Erin McKenna Breglia, Landis Gardener

From the Garden: Milkweeds for Monarchs!

Many people enjoy seeing butterflies in our Landis gardens. especially the monarch butterfly, Danaus... read more

May 28, 2022 | Anita Sanchez

Life and Death on the Lawn

It’s a beautiful summer day. You’ve finished your stack of books from the Landis... read more

News Archive