PINE DISEASES 275 



Even with these facts known, no definite action was taken 

 in the United States to prevent the introduction of this fungus, 

 and in 1906 it was first found at Geneva, New York. Later, 

 in 1909, it was discovered in recently imported seedling stock 

 in New York, Vermont, New Hampshire, Massachusetts, 

 Connecticut, Pennsylvania, Indiana and Ohio. The demand 

 for white pine nursery stock both for forest and ornamental 

 plantings had far exceeded the amount produced in this country 

 at that time, and several hundred thousand trees had been im- 

 ported annually from Germany and France. It is, therefore, 

 not surprising that numerous diseased pines were found in the 

 different states where this stock was planted. Although at- 

 tempts were made to eradicate the known diseased trees, the 

 fungus is now generally prevalent in the New England states. 

 and New York and is known in restricted areas in Wisconsin 

 and Minnesota. 



All pines which have their needles in fascicles of five are ex- 

 pected to be susceptible. It is definitely known that the 

 eastern white pine, western white pine and sugar pine are 

 susceptible. As yet the fungus has not been found in western 

 United States where the two important western species of 

 this group grow. The damage that may result to the five- 

 needle pines in the forest in this country cannot be prophesied 

 at this time. Young trees and the younger branches of older 

 trees are most seriously affected. In plantations of European 

 stock in New York state not more than one per cent of the 

 trees were ever found affected. However, in several places 

 under actual forest conditions in northeastern United States 

 where the fungus has existed unnoticed for many years, a much 

 larger percentage of the stand is affected. 



The fungus causing white pine blister-rust requires the pres- 

 ence of some species of gooseberry or currant for the comple- 

 tion of its life history. The spores developed on the pinifes 

 cannot infect other pines but must lodge on the leaves of cur- 



