4. Testing: Chips 

 of wood are 

 placed on spe- 

 cial fungus 

 food in cul- 

 ture dishes. 



ood Sample 



egins with a diseased 

 V, Dutch elm disease 

 ranch tips to curl and 

 , and fail. The picture 

 it happens when such 



U. S. D. A. Photo 



5. Diagnosing and Recording Results: After a few days fungus in the 

 wood may be identified by its r«r<^>"th in the culture dishes. 



6. Under the Micro- 

 scope: Dutch elm 

 disease fungus 

 growing around 

 chips of elm 

 wood. 



