aUICK ACTION 

 ELMS 



Bark sh'ipped from a dying elm ex- 

 posing curious design of larval gal- 

 leries made by Dutch Elm disease 

 carrier beetles. 



Pholo by Robert L. Coffin 



By DAVID H. MARSDEN * 



Fig. 6. Elm tree affected by Dutch Elm disease. Arrow points to wilted foliage and other symp- 

 toms. Pruning the limb at the main trunk indicated by white marker might save the rest of the 

 tree. 



UNCEASING VIGILANCE and 

 quick action with a saw may 

 save many desirable elms from 

 the deadly, quick-spreading Dutch 

 elm disease. The chances of saving 

 affected elm trees by pruning out 

 diseased parts were tested by the 

 Shade Tree Laboratories in small 

 scale trials during the summers of 

 1950 and 195L 



In Amherst and vicinity, 31 elms 

 were discovered with symptoms 

 typical of those appearing during 

 the early stages of Dutch elm dis- 

 ease. Each tree was operated on 

 promptly to remove the affected 



* Assistant Research Professor, Shade Tree 

 Laboratories 



parts, thus preventing further 

 spread of the disease in the sap 

 stream; in most instances, the 

 pruning was done within 24 hours 

 of the discovery of discolored and 

 wilting foliage. Samples of wood 

 from the cut branches were tested 

 for the presence of disease organ- 

 isms. Of the 31 trees suspected of 

 Dutch elm disease, 24 were har- 

 boring the disease fungus, and the 

 other seven were affected with 

 lesser diseases. Of the 24 trees that 

 had Dutch elm disease, 15 were 

 healthy by the end of the 1951 

 growing season, apparently because 

 of the prompt removal of the af- 

 fected parts. 



14 



