REPORT OF THE SECRETARY. 55 



plete victory over the combination of fungous diseases and insect 

 enemies. The promptness with which peach growers have accepted 

 the discoveries is encouraging. The growing of fine peaches has 

 received a great impetus through the removal of some of the factors 

 which render the growing of this fruit uncertain. 



On the Pacific coast the work of controlling pear-blight by eradi- 

 cation methods has been successfully carried out. In the Rogue 

 River Valley of Oregon and in many districts of California the disease 

 was decidedly less prevalent during the past season than at any time 

 since the blight entered. 



It has been demonstrated on the Pacific coast that the powdery 

 mildew of the apple can be satisfactorily controlled by spraying. 



Experiments in spraying for pecan scab were continued in South 

 Carolina, and similar experiments were started in Georgia. Though 

 the disease can be controlled by spraying, the desirability of avoiding 

 it by the use of resistant varieties was made clear. Many of the com- 

 mercial pecans are sufficiently resistant to serve the purpose admira- 

 bly and may be top-grafted on affected varieties. 



Studies in forest pathology. — The chestnut-bark disease has 

 now spread to northern Massachusetts and New York, western 

 Pennsylvania, and eastern West A^irginia. There are, however, 

 certain indications that it may not become serious south of the 

 Potomac. The work of tliis Department has shown that with young 

 ornamental trees and orchard trees the disease may be controlled by 

 a cutting-out and pruning system, though this method is impracti- 

 cable with large ornamental trees and forest trees. In localities 

 where the disease is just appearing its progress can be materially 

 checked, and perhaps prevented, by promptly cutting down the 

 infected trees and burning up at least the bark and brush. After 

 25 per cent of the trees are infected it is too late to do anything. It 

 is unfortunate that in matters of this kind greater cooperation by 

 private owners is not possible. Had tliis disease started in a National 

 Forest district having a cooperating pathologist it probably would 

 have been eradicated as a matter of routine before infection became 

 general. 



Wliite-pine seedlings diseased with blister rust appear to have 

 been imported into some 230 localities in North America. All 

 diseased seedlings thus far located have been destroyed, but it is 

 by no means certain that all importations have been found. This 

 disease afTects mature trees, as well as nursery stock, and occurs not 

 only on the white pine, but on the sugar pine, the western white 

 pine, and probably all other live-necdled pines. The importation 

 of white-pine seedlings should be flatly proliibited, as the damage 

 which this disease can do, and probably will do, if once established 

 in America, is out of all proportion to the value of all white-pine 



