218 MANUAL OF FRUIT DISEASES 



diseased ; for there is a slight possibility of their carrying the 

 blister-rust fungus over winter. 



Considerable effort has been made to date to control the dis- 

 ease with reference to the five-needle pines. So far, however, the 

 work has not been wholly successful. The difficulties involved 

 are these : (1) There has never been any attempt previously, 

 in Europe or America, to eradicate a tree-fungus of this sort; 

 so there is no past experience on which to base the procedure. 

 (2) The fungus incubates, or lies dormant without showing 

 itself externally, for a period varying from one to six or more 

 years; thus inspection has been inefficient. Diseased trees 

 have been overlooked. (3) Neither the federal nor the various 

 state officials who must carry on this inspection have the power 

 to destroy the currants and gooseberries found within the 

 danger zone. (4) The people generally do not realize the 

 seriousness of the blister-rust disease, and therefore cooperation 

 has not been unanimous. 



With the knowledge of the disease now available it seems 

 likely that rational measures may be employed even in the 

 absence of previous experience. On account of the long in- 

 cubation period of the fungus in the pine, annual inspections 

 are necessary, unless, of course, the whole group of pines be de- 

 stroyed immediately on discovery of the disease. Special 

 emphasis is laid on the destruction of wild currants and goose- 

 berries, for the uredospores may spread from plant to plant for 

 many miles during the summer. There is great need for ade- 

 quate state laws. Inspectors should be regarded as friends of 

 the people rather than as personal enemies to the fruit-grower 

 or the forester. Their presence should be taken as an index of 

 precaution against calamity rather than of any ill-influence of 

 a supposedly antagonistic citizen. Such officers not only need 

 cooperation, but, unfortunately, as experience has shown, they 

 need legal power to compel concerted action in the eradication 

 of diseased plants. In most cases the removal of currants and 



