170 TRANSACTIONS OF THE ILLINOIS 



fungus {fnskladhim) when it develops on the leaves. The falling 

 of the leaf, due to Morthiera, has, how^ever, so long been known as 

 leaf-blight in this State and elsewhere that it seems best to retain its 

 use in this connection, especially as the damage it causes to the 

 foliage is far greater than that of any other fungus. 



The disease hrst manifests itself as small black spots, often sur- 

 rounded by a reddish border scattered over the surface of the leaf. 

 Minute pustules containing the curious compound, flaggelate spores 

 characteristic of this species, are soon developed in the center o£ 

 these spots; and the leaf turns yellow and falls. This premature 

 falling of the leaves often causes great damage. I have seen an 

 orchard of three thousand Louise Bonne trees as bare of leaves by 

 the Fourth of July from this cause as they should have been at 

 Christmas. The fall rains brought out a new set of leaves, and such 

 fruit buds as were already formed bloomed, thus destroying all 

 chance for a crop the following year. 



Some varieties are much more subject to this disease than 

 others. Out of an experimental orchard of a hundred and twenty 

 varieties, planted at Colxlen some years since, all but ten or twelve 

 were so badly affected by it as to be discarded as worthless. Of the 

 varieties in general cultivation Lawrence, Anjou and Duchess may 

 be mentioned among those most exempt. Bartlett and Seckel some- 

 times suffer from it quite severely. The fungus also develops on 

 the fruit, causing it to fall prematui-ely, and in many cases inducing 

 the unsightly cracking of the surface so destructive to some varieties. 



No remedy is known for the leaf-blight, but, as a general rule, 

 trees standing in sod are less affected than those under cultivation. 

 It is greatly affected by climatic conditions, being worse during damp, 

 hot weather. By a careful selection of varieties, and the early seed- 

 ing of the orchard, serious loss from this cause can be avoided, ex- 

 cept in occasional unfavorable years. In many parts of the country 

 young seedlings suffer so severely from this disease that it is impos- 

 sible to raise healthy stocks for grafting. It does not attack apples, 

 but quinces and some other pomaceous fruits suffer from what is 

 probably the same fungus. The leaf-blight of the apple, supposed to 

 be connected with the so-called " red cedar apples," is an entirely dif- 

 ferent fungus. 



THE SCAB. 



(Fusicladuim pyrinum Fckl. ) 



■ This ubiquitous disease has received comparatively little atten- 

 tion from either fruit growers or botanists, but the damage it has 

 caused in the past dozen years entitles it to the foremost place among 

 pear diseases. A hundred times as much has been written about 

 blight as about scab, and yet of what avail is it to plant an orchard, 

 and by care and watchfulness, steer it past the danger of blight on 

 one hand, and root-rot on the other, if, when it comes into bearing. 



