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Cooperative Extension Service
Colorado State University
Fort Collins, Colorado
August 20, 1979 80523
Norman Carlson, Chairman
Board of County Commissioners
P.O. Box 758
Greeley, CO 80631
Dear Norman:
The Colorado State Forest Service's (CSFS) Dutch elm disease (DED) project
is in its ninth year. Lessons already have been learned from this project, the
most important being the need for prompt removal and disposal of diseased elms
as well as standing dead trees and elm firewood that can serve as breeding sites
for the elm bark beetle that carries the DED fungus.
Eaton is an excellent example of a community in Weld County where this
rapid removal and disposal technique has been shown to work. During 1978 when
a special control demonstration project was first started, 47 large-leaf elms
were diagnosed as infected by DED in and around Eaton. These were removed
within 20 days following notification by the CSFS. During 1978 three other
trees were removed in Eaton's project area (includes a 2 mile buffer zone of
county land) to eliminate its use as beetle wood.
So far this year Eaton has lost only 2 large-leaf elms to DED. These
trees, like those last year, were removed within 20 days of notification.
As a result, Eaton still has more than 98% of their large-leaf elm population.
A remarkable control record in such a short period of time.
Other areas of the state are not faring as well as Eaton. CSFS survey
crews and district foresters are continuously identifying diseased and beetle-
infested elms. Some counties and communities, however, are neglecting to
remove these trees.
Weld County has approximately 8,000 large-leaf elms, most of which are
American elms. The majority of these are within the city limits of the various
communities in the county. An additional 130,000 Siberian elms are within the
county limits, most planted in windbreaks. Dead and dying Siberian elms are
being tagged by the CSFS and their removal being recommended to the city
forester, county pest inspector or other county appointed personnel.
790 54 3
Colorado State University and U.S. Department of Agriculture Cooperating
Norman CarlsDn
August 20, 1979
Page 2
Siberian elms that die and are not removed, like American elms, contribute
to the spread of Dutch elm disease. In fact, any dead or dying elm wood is a
possible breeding site for the elm bark beetle. A concerted effort needs to be
made to remove dead and dying elms as well as elm firewood. DED can be controlled
and Colorado's American and other large-leaf elms can be saved if everybody works
together.
For more information on how you can help in the battle against Dutch elm
disease contact Vince Urbina, CSFS District Forester, at 482-9512 in Fort Collins.
Sincerely, ceu\<< .
Curtis E. Swift,'
Extension Agent
Dutch Elm Disease Project
C219 Plant Science Building
Colorado State University
CES/hm
xc: Vince Urbina, CSFS
Mike Schomaker, DED Project
Leader, CSFS
CrU
Colorado State University
Colorado State Forest Service Fort Collins, Colorado
80523
DED CONTROL PROJECT UPDATE:' August 17, 1979
Canon City: 280 Positives: 136 city, 144 county; all are American elms.
Large-leaf elm disease rate: 5.27.
144 Beetle trees: 17 city (all are American elms),
127 county (85 American, 42 Siberian elms).
Eaton: 4 Positives: 3 city, 1 county; all are American elms.
• Large-leaf elm disease rate: 3.17.
28 Beetle trees: 2 American, 26 Siberian elms; all are in county.
Grand Junction: '4 Positives: 3 city, 1 county; all are American elms.
Large-leaf elm disease rate: approx. 1`7.
286 Beetle 'trees: 195 city (28 American, 167 Siberian elms).
91 county (8 American, 83 Siberian elms) .
La Junta: 19 Positives: 14 city (11 American, 3 English elms) ,
5 county (all are American elms).
Large-leaf elm disease rate: 0.5%
191 Beetle trees: 106 city (9 American, 10 English, 87 Siberian elms),
85 county (17 American, 1 English, 67 Siberian) .
Yuma: 6 Positives (all city, all American elms)
Large-leaf elm disease rate: 1.5%
144 Beetle trees: 98 city (1 American, 97 Siberian elms),
46 county (all are Siberian elms).
All trees have been removed.
S. J. Krieg• ,ly • 1[�1
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