Wood pathology 



Investigations of defects in wood 

 and wood products caused by fungus 

 infection are conducted at the Labora- 

 tory by the Division of Forest Path- 

 ology, Bureau of Plant Industry, United 

 States Department of Agriculture, in 

 correlation with other Laboratory 

 activities. 



Wood-destroying fungi 



The effects of wood-destroying fungi 

 upon the structure and service life of 

 wood are examined, and temperature 

 and moisture conditions favorable and 

 unfavorable to fungus growth are de- 

 termined. The causes of decay in 

 buildings and wood products are in- 

 vestigated. Rules of construction for 

 the avoidance of decay have been de- 

 veloped, with consequent large savings 

 to thousands of home owners. 



in pure cultures. The adaptation of 

 various chemicals to mechanical or 

 hand-dipping treatments of freshly 

 sawed lumber is a phase of the studyBj 

 having wide commercial application in 

 the prevention of sap stain during air 

 seasoning. 



Yard sanitation 



Heavy losses to users occur as a 

 result of the storage of wood under 

 improper conditions of drainage, ven- 

 tilation, and exposure. Studies and 

 recommendations are made, in coopera- 

 tion with other divisions of the Lab- 

 oratory, for improving storage of gen- 

 eral lumber stocks at sawmills and 

 retail yards and for the better storage 

 of pulp wood and pulp, box lumber, 

 veneers, staves, vehicle parts, and 

 other wood products. 



Toxicity of preservatives 



The toxicity or fungicide value of 

 wood-preservative chemicals is deter- 

 mined by their effects on typical wood- 

 destroying and staining fungi grown 



A blue-stain fungus in wood (magnified). 



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A decay fungus in wood (magnified) 



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