Spray Calendar. 53 



FOR CRATER BLIGHT OF PEARS. 



Prof. C. W. Woodworth, of BerkeleVj California, says: "The 

 nature of the disease is somewhat obscure, but the evidence seems 

 to be that it is caused by an organism, and is very similar to the 

 ^ dreaded eastern pear blight. It is not, however, the same disease. 

 Crater blight first appears as a darkened spot, indistinguishable 

 from any other fonn of blight. Like other blights, it commonly 

 begins at the point on a branch where a twig is given oft', or where 

 one has been. There is this difference, however : The crater blight 

 extends out only below the point of origin, whereas in other blights 

 the disease extends upward as well. The most characteristic fea- 

 ture of this blight is the sharp line of demarcation between the dead 

 and live bark. When a spot has ceased to spread there occurs 

 a breaking in the bark, separating the diseased portion. This soon 

 dries, and the spot appears like a crater. The appeai^ance is most 

 striking when isloated spots are seen on the larger branches. ' ' 



Treatment — Cut out the dead and diseased tissue, clean and wash 

 with bordeaux mixture; cut off all dead and blackened limbs. 



Under date of July 27, 1896, Professor Woodworth adds: "We 

 have made some progress in the study of the disease, in that we 

 are very uniformly able to obtain pure cultures of a peculiar bacil- 

 lus. Inoculation experiments have so far given only negative re- 

 sults. The disease occurs on many varieties of pears and only a 

 few apples. The crater blight certainly occurs in Oregon. I have 

 had very typical examples from there, and obtained the usual bac- 

 terial cultures from it. Economically, the crater blight in most lo- 

 calities is unimportant, but in some places it has done an immense 

 amount of injury." 



FOR PEAR SCAB, CRACKING, AND LEAF BLIGHT. 



These diseases, caused by two different species of fungi, are suc- 

 <>essfully combatted by one line of treatment. In most sections all 

 three diseases are found associated. Bordeaux mixture has given 

 the best results in this work. The first spraying for these diseases 

 should be made just before the buds swell. In 10 or 12 days the 

 second treatment should be given, followed by a third and fourth 

 at the expiration of two and four weeks, respectively. In the nur- 

 sery, pear blight is often exceedingly troublesome. It may be al- 

 most entirely prevented by spraying five or six times with the bor- 



