With the cold weather my reading hobby kicks into higher gear. More and more of what I read is on the internet or even :gasp: on my cell.

Here is an interesting little thing from the Arnold Arboretum. I read it imagining replacing every reference to DED with EAB. How little times have changed.

Interesting reference to the arrival of Metasequoia seeds at the end.

"

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ARNOLDIA

A continuation of the

BULLETIN OF POPULAR INFORMATION

of the Arnold Arboretum, Harvard University

VOLUME 8 APRIL 30, 194H NUMBER 4

DESTROY DEAD ELM WOOD IMMEDIATELY

M U CH has been written in the past months concerning the Dutch Elm Disease

and its effective control. "Spray now and save your elms," "Contribute

to this fund now and save New England’s elms," are only two of several

headlines originating from various sources, to try to force the property owner into

spending money in certain ways for the so-called "control" of the disease. Unfortunately,

such headlines are most misleading, and property owners are due a

thorough report of the Dutch Elm Disease situation as it appears at the present

time.

It must be admitted that the Dutch Elm Disease has come to stay, and will be

with us a long, long time. We hope that it will not be responsible for eradicating

all the elms of New England, but it will continue to be an ever-present menace

for a number of years. Regardless of what the final control solution will be, there

are thousands of elms in remote places which can harbor the disease or the insects

carrying the disease, or both -trees which are growing on inaccessible land

or which are on such cheap land that it will not pay to treat them for the disease.

This fact is not pleasing to contemplate, but it must be considered when discussing

a practical means of control.

A general meeting of scientists working on the control of this pest in New

England, was called on November 7, 1947, by the New England Council in the

Statler Hotel, Boston. Present were competent representatives from all the New

England State Experiment Stations as well as from New Jersey and Maryland.

Present also were representatives from the U. S. Department of Agriculture and

certain Canadian Experiment Stations. In other words, this was a general meeting

of all the interested scientific groups doing research on control problems for

the New England area. Many of the men have been working on some phases of

control as major research projects. This is not the place to discuss all the research

projects under way at the present time, nor to study a history of control methods

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used earlier in Ohio, New Jersey and New York. Certain facts were brought out

during the course of these discussions which might be of interest to New England

property owners, and it would seem advantageous to discuss a few at this time.

’

No Practical Control of Disease Fungus Yet

There is no practical method of spraying to control the disease fungus once it

is in living trees. All spraying attempts are directed towards controlling the insects

on the trees.

No Positive Practical Control by Spraying of the Bark Beetles

As most people know, there are two types of bark beetles which feed in the

bark of dead or diseased trees and are responsible for carrying the fungus to living

trees. Many statements have been made erroneously, that spraying will definitely

control these insects. Unfortunately this is not true. It is practically impossible

to cover all the small twigs of elms with sufficient spray materials to adequately

kill insects in all parts of the tree. It is true that DDT kills bark beetles, but

only when used in far greater quantities than has ever been used before on trees

-quantities such that the price of spraying is often prohibitive for all practical

purposes. The actual mechanics of applying these concentrated sprays, even with

the latest types of blowers or hydraulic equipment, presents many serious problems

which, it is hoped, will be solved with more experimentation. Consequently,

thorough control of the bark beetles can not be obtained by spraying this spring

with the equipment and materials normally in use at the present time.

Sanitation is the Best Present Control Method

Sanitation would include several things. First, it would include the removal

and destroying of all dead elm wood. This is best done by burning immediately.

Elm wood can also be stored indoors so that when bark beetles emerge they can

not fly out-of-doors. Spraying dead elm wood with oil (1 lb. of DDT in 1~~ gallons

of No. 2 fuel oil) on all sides has also proved an effective means of preventing

the emergence of bark beetles and of killing them if they alight on such treated

wood. Immediate burning, however, is best. Elm wood, dumped in piles, or

thrown about miscellaneously at town dumps can serve as a source of disease infection

for the entire community, unless it is burned or thoroughly sprayed immediately.

Elm logs over a year old do not serve as likely sources for hibernatingg

beetles, but freshly-cut elm logs do.

Completely removing the bark of all logs as soon as they are cut, or keeping

them completely submerged under water has also been recommended, but these

methods are rather difficult to carry out properly.

Sanitation would also include the prompt removal and burning of dead elm

branches on normally healthy trees.

Fertilizing the trees to keep them in a healthy, growing condition could easily

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be construed as being part of the general sanitation program. Many an elm growing

in a prominent position bordering a street or on private property is a worthy

subject for proper tree fertilization. This tends to keep such a tree in a vigorous

growing condition and reduces to a minimum the number of weak spots where

infection might possibly take place. It should be kept in mind, however, that

even this is no cure nor is it a positive prevention measure.

Spraying for leaf-eating insects such as the elm leaf beetle, elm leaf miner,

canker worm, gypsy moth and several other pests is also included in general

sanitation measures. When such insects feed on the foliage of a tree in large

numbers, the tree is weakened considerably and becomes easy prey to bark beetles

and possibly disease infection. So, proper spraying of the fohage for leaf-eating

insects by any acceptable means used at present, would greatly aid in keeping

the trees in a good, clean condition. Competent entomologists have suggested

that three sprays might be used in eastern Massachusetts for maximum protection ;

May 15, June 15 and July 15, although these times might vary slightly with

weather conditions.

The Massachusetts Arborists Association is to be complimented on its statement

of policy which emphasizes this sanitation program. Such a decision to make public

this policy and not to flaunt popular hysteria in spraying primarily for the bark

beetles when sanitation seems to be much the best approach to the problem under

present practical conditions and with present available materials, shows that these

commercial arborists are Bery definitely trying to give the public the best information

available at the moment on this troublesome and confusing situation.

What One Town Has Done

Williamstown, Massachusetts, is one New England community which has vigorously

attacked the Dutch Elm Disease and worked out an excellent local solution,

which might well be adopted by other communities. With an energetic local

committee of civic leaders, experts and citizens, a program of action was advanced

leading to the cleaning up of all dead or dying elm wood in the community.

Frequent announcements were made in the local newspapers, various civic organizations

obtained volunteers to donate truck services and men to load and carry

off dead elm wood, students in the high school and local garden clubs assisted in

the hunting for dead and dying trees, property owners combed their wood piles

out-of-doors for elm wood and removed it and local funds were made available so

that a trained investigator assisted in a property-by-property investigation for

dead elm wood. Much was accomplished in this sanitation program by a thoroughly

aroused community. The credit for clean trees in this town goes directly to an

intelligent and energetic committee, which knew what the local problem was, and

took the proper steps to make every property owner morally responsible for assistance.

Programs similar to this can be launched in other communities, the sooner

the better. -

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No more fitting conclusion could be given than to emphasize the four points

stressed by the Massachusetts Arborists Association in recommending that, for

this spring, the Dutch Elm Disease should be fought in Massachusetts by :

1. Careful pruning to remove all dead and dying branches.

2. Maintaining fertility by judicious use of plant foods.

3. Prompt destruction or protection of all cut elm wood.

4. Spraying to control leaf-eating insects such as canker worms, gypsy moth

caterpillars, elm leaf beetles, and other destructive pests.

DONALD WYMAN

NOTES

A very large shipment of Metasequoia seeds has just been received from Szechuan

(see Arnoldia Vol. 8, No. 1, March 5, 1948). Packets of these seeds will be sent

to all readers of Arnoldia, who request them, as long as the supply lasts. It is by

no means certain that this tree will prove to be hardy in the northern tier of States.

Field Class

It is not too late to register for the Arnold Arboretum Field Class, conducted

for two hours every Saturday morning in May. The second meeting is on Saturday,

May 1, at 10 a.m. at the Forest Hills Gate. Registration is in advance by mail.

Through the efforts of Professor Stephen Hamblin, Assistant Professor of Horticulture

in the School of Design, Harvard University, the Lexington Botanic Garden

has presented the Arnold Arboretum with over 100 old-fashion roses. These

have been collected from many sources in this country and abroad during the

past ten years. The collection contains many varieties of Rosa gallica, R. centifolia

and certain hybrids. They will be grown and observed in the nurseries at the

Case Estates, Weston, for a few years, after which the better ones will be added

to the collection in the Arnold Arboretum. The Arboretum wishes to take this

opportunity to thank Professor Hamblin and the Lexington Botanic Garden for

this valuable gift of plants.

Here is a link that might be useful: Arnold Arboretum PDF