80 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 5 



does attack the young trees. A specimen of this was sent to the 

 speaker by one of the keenest of the Eastern nurserymen. This tree 

 had been in his nursery for three years, and was originally imported 

 from Europe. 



Still another disease which has entered this country already is caused 

 by one of the Japanese cedar apples. It was imported into the State 

 of Connecticut upon the Japanese cedar and was there discovered by 

 the Connecticut authorities. This has its alternate stage upon the 

 Japanese pear and the quince. The pear industry of an entire province 

 in Japan was threatened with extinction by this disease until the 

 connection between the fungus upon the pears and the cedar apple 

 was determined. The removal of cedars from the vicinity of the 

 orchards apparently has quite largely controlled the trouble. It is 

 not known at present whether this particular disease will attack 

 American species of pear or of cedar, but this disease is one which 

 should be watched until some definite information about it is obtained. 



Another disease, known as the European pine twister, caused by 

 one of the blister rusts known as Caeoma pinitorquum, may be consid- 

 ered dangerous. This attacks especially young trees varying in age 

 from newly germinated seedlings up to 20 and 30 years, and in excep- 

 tional cases even 40 and 50 years of age. This has its alternate stage 

 upon the European aspen and is apparently very prevalent throughout 

 the European countries. The attacks of this disease where the branches 

 are not killed, result in a twisted growth from which it receives 

 its name. It results in the crippling of the tree so that in future years 

 it is practically useless for timber. This disease is one about which 

 little is known in connection with American species. It is not known 

 to attack American species in either stage, but until definite information 

 upon this point is obtained this should be kept from entering the 

 country. 



Finally may be mentioned the European oak mildew, which has 

 been causing very considerable alarm throughout Europe because of 

 its extreme attacks upon the European species of oak. It was first 

 noted in 1907 in France, in 1908 it was prevalent throughout Europe 

 except in the northern countries. It was so virulent in its attacks that 

 in many places the entire undergrowth and lower branches of large 

 trees to a height of about six feet were white with the mildew upon the 

 leaves. The origin of this disease is not known at present, and until 

 this is known this disease should be especially watched for in impor- 

 tations. 



In these remarks the speaker has confined himself largely to tree 

 diseases, as information upon the diseases of other classes of plants is 

 not immediately available. 



