248 Twenty-Second Annual Report of the 



successful until this year, when a new area of infection was found 

 in Chautauqua county. Several years ago over a million white 

 pine seedlings that had been exposed to infection were destroyed, 

 and during this year another plantation of upwards of 60,000 

 trees were destroyed because it was to a large extent diseased. It 

 is true that many healthy trees were destroyed at these times; it 

 was decided by the authorities that it was much better to burn the 

 entire lot rather than run a risk of distributing the disease broad" 

 cast throughout the State. 



The disease is a peculiar one to the uninformed. The fungus 

 remains perennially in the pines, and in the trees until they suc- 

 cumb, except that in the summer the spores are distributed and 

 blow broadcast, taking lodgment on plants of the Ribes type, in- 

 cluding our wild and cultivated currants and gooseberries. On 

 the currants and goosberries the disease is known as Ribes ribicola, 

 or felt-rust. It may appear on the underside of the leaves, par- 

 ticularly of black currants, quite late in the fall, though in time 

 to perfect the development of the fungi and the distribution of 

 spores to pine trees, where new or secondary infections begin. 

 The disease is destructive to the pines but seems not to injure the 

 growth of the currant or gooseberry bushes. 



Investigations were made last spring, and several lots of cur- 

 rant bushes known to have been infected by the currant rust in 

 1914 were sent to several botanists for a test. They were widely 

 distributed over the country, planted in greenhouses and watched 

 with miscroscopic care. In no case did the disease appear on the 

 currants, thus confirming the statement made by all writers on 

 the subject of the disease, that the disease does not carry over 

 winter on Ribes. 



The above description of the method of spread of the disease in 

 pine trees indicates the only remedy known for the suppression of 

 the disease after it becomes established; namely, the absolute iso- 

 lation of either the pine trees or the currant bushes. The disease 

 can only be spread when these two species of plants are in proxim- 

 ity, and the disease must stop its spread if one or the other of the 

 plants is eliminated. 



The Department has ruled that the form of the disease on the 

 currants and gooseberries is not injurious to. nor destructive to 



