444 MINNESOTA STATE HORTICULTURAL SOCIETY. 



from Canada or some eastern states — will not succeed in Min- 

 nesota. In the East, and likely in Russia, too — of which, how- 

 ever, I am not positive — the climate in general is more humid. 

 There evaporation cannot take place as fast as in Minnesota, 

 and the little moisture the trees lose they are always able to sup- 

 ply. Hence our fruit trees must not only have the power to 

 withstand the cold, but they must likewise have the inherent 

 quality to resist the drying efifects of the climate. The Duchess, 

 Hibernal and a few of their seedlings have this inherent quality 

 to resist evaporation in an eminent degree, while hundreds of 

 Russian varieties of apples and pears seem to be deficient in 

 this one particular. The result is that all of them fail in Min- 

 nesota. Of course there may be other reasons why they do not 

 succeed well here and in other states, but of these I have no 

 knowledge. 



APPLE RUST. 



PROF. SAMUEL B. GREEN, ST. ANTHONY PARK. 



Recently I visited the orchard of a friend of mine, an orchard 

 I had not seen for seven or eight years. The trees as a whole 

 were healthy and well loaded with fruit, except for a row of 

 Wealthy s close to a red cedar hedge, and this was so badly injured by 

 leaf rust that more than half of the foliage had fallen from the trees 

 and that which remained was badly injured and was unsightly, and 

 the crop of fruit from these trees was of little value. 



On examining the red cedars I found they were full of the little 

 hard swellings commonly known as "cedar apples." I was sure then 

 that I had found the source of the leaf rust on the Wealthy trees. 

 These trees were shaded by the red cedar and the foliage kept moist 

 most of the day, and even in quite dry weather the foliage did not dry 

 off until late in the forenoon. I found that my friend was not in- 

 formed as to the close connection between the swellings of the cedar 

 apples on the cedar trees and the leaf rust on the apple trees. 



It should be more generally known that wherever leaf rust is 

 found on the apple trees the red cedar must be near by, since the dis- 

 ease cannot live more than one generation upon the apple, and the 

 next generation it must live upon the red cedar. This life history in 

 plants is frequently referred to as "alternation of generation," and it 

 is found in a number of other parasitic plants. Under such condi- 

 tions the removal of the rust from the apple, or the removal of the 

 apple trees, would undoubtedly result in the removal of the cedar ap- 

 ples from the cedar trees. 



Mv friend is rather loath to cut down his red cedar windbreak 

 and will try to overcome the difficulty bv spraying. He has, however, 

 a hard proposition to do so satisfactorily. 



