OF ELM DISEASES IN MASSACHUSETTS 



By FRANCIS W. HOLMES, Shade Tree Laboratories 



WILTED foliage on an elm tree in summer may mean Dutch elm 

 disease. To find out why his elm is dying, the homeowner or town 

 tree officer sends twigs clipped from the wilted part of the tree to the Uni- 

 versity Shade Tree Laboratories. 



Laboratory cultures are then carefully prepared from the samples. 

 Usually Dutch elm disease is confirmed, but sometimes another disease is 

 found responsible for the wilting. 



Shaded areas on the outline maps on these pages represent towns in 

 which the most common elm diseases have been rampant during the last 

 twenty years in our state. 



DUTCH ELM DISEASE 



Dutch E/m Disease. 

 First discovered in 

 Massach usetts in 

 1941, this disease is 

 now found in 334 of 

 our 35 1 towns. It 

 attacks only the elm 

 trees. Unless the wil- 

 ted branch can be cut 

 off before the fungus 

 spreads, the infected 

 tree is almost sure to 

 die. We can protect 

 our elms by destroy- 

 ing the breeding 

 places of the elm 

 bark beetles that 

 carry the disease to 

 healthy trees. Any 

 dead elm wood with 

 rough bark should be 

 burned promptly to 

 prevent beetles from 

 laying eggs. 



Cephalosporium Wilt. 

 Similar in appear- 

 ance to Dutch elm 

 disease, cephalo- 

 sporium wilt con be 

 identified only 

 through laboratory 

 tests. Some elms re- 

 cover from this wilt 

 disease, but others 

 die slowly over a 

 period of years. Such 

 trees may become 

 dangerous breeding 

 places for the bark 

 beetles that carry 

 the Dutch elm dis- 

 ease. 







CEPHALOSPORIUM WILT OF ELM 



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