328 BROOKLYN BOTANIC GARDEN MEMOIRS 



bulletin lists about 2,700 such insects and that it also lists 130 

 important insects which have already been introduced into the 

 United States. If a thorough canvass was made of foreign literature 

 I have no doubt that as many plant diseases could be located and 

 described which are likely to be introduced into the United States, 

 and many of them produce as much devastation as the chestnut bark 

 disease, the asparagus rust, the potato blight, the citrus canker, or 

 many other diseases that could be named. Unfortunately, we have 

 at present no corresponding manual of plant diseases that are likely 

 to be introduced into the United States. 



There has never been a time when the danger from imported 

 diseases and pests was so great as now. Commerce in living plants 

 has in recent years extended to the ends of the earth. I have in mind 

 one nursery company which makes a specialty of novelties from the 

 Orient. This company is distributing throughout the United States 

 plant material from all parts of Asia. Most of the things that they 

 bring in are woody plants, many related to our American species, and 

 on account of our comparative ignorance of the botany and zoology 

 of the Orient we have no idea what diseases and pests are coming in 

 with Oriental material. The San Jose scale, the chestnut blight, and 

 the citrus canker are only a part of those that have come in already. 

 Not only is commerce being carried on with countries from which 

 hitherto there have been only scattering importations of live plant 

 material, but material brought in now is much more miscellaneous and 

 reaches this country in a much shorter time. There is at present a 

 limited amount of port inspection but too limited to be efficient and 

 the canker diseases and many insects can not be detected by any 

 sort of inspection. The roots of plants imported with earth about 

 them can not even be inspected and such plants constitute a par- 

 ticularly dangerous class of imported material. 



The white pine blister rust (caused by Cronartium ribicola Fischer), 

 which I am here considering as a fairly typical example of the imported 

 disease, has long been known in Europe. It apparently originated in 

 Asia and spread in Europe upon Finns cembra. When the American 

 white pine {Pinus strohus) was introduced into Europe it proved sub- 

 ject tq the disease. The first authenticated record of importation of 

 white pine transplants from Europe to the United States dates back 

 only to 1899. From that time until prohibited by law such importa- 

 tion was extensive, as such transplants could be imported more cheaply 

 than they could be grown in America. There was, furthermore, a 

 prevalent belief among nurserymen that white pine seedlings could 

 not be successfully grown in America, a belief which has since been 

 proved erroneous. 



