TREES AND TIMBER 445 



Spraying has proved effective. 



Microsphaerose {Microsphcera alni Wallr.). — Certain 

 years in the South the pecan crop has been practically 

 destroyed by this mildew. It is recognized as a flour- 

 hke, white coating particularly damaging over the young 

 nuts. 



Spraying with Bordeaux mixture before the fungus 

 appears is effective. Burning of infected fall refuse is also 

 helpful. 



PINE 



Bluing (Ceratostomella pilifera (Ft.) Wint.). — The char- 

 acteristic symptom, bluing of the sapwood, begins in 

 August and September after the trees have been attacked 

 by beetles.^ The blue color starts near the base of the tree 

 and gradually spreads upward until the entire sapwood is 

 blue. The cause is the presence of the mycelium of the 

 above-named fungus, which gains entrance through openings 

 made by the beetle and is initiated by spores carried 

 by the beetle. 



Blue wood is as strong as normal green wood, is tougher, 

 and when dry, it will last as long ; but when wet, it rots 

 rapidly. 



Hypodermose {Hypoderma Desmazieri Duby). — The 

 needles die from the tips toward the bases, becoming first 

 reddish, then gray. Black lines which extend lengthwise 

 of the leaves are the ascus-bearing organs. 



Premature defoliation results. 



Leaf blight, twig blight (Lophodermium hrachysporum 

 Rostr.). — In Maine the leaf blight has been noted as 



' von Schrenk, H., U.S. Dept. Agr. Bur. Plant Indus. Bui. 36. 



