REPORT OF STATi: HORTICULTURIST. 57 



THE WHITE PINE BUSTER RUST. 



This disease has been introduced through foreign nursery 

 stock, and unless carefully guarded against will work havoc 

 with our white pine. 



As far as we know, there are no infested trees in this State, 

 but the nature and importance of this disease should be known 

 so as to guard against future introduction. 



It does not show on the white pine for some time, usually 

 a year or more, and then on three-year-olds or those older. 

 The bark swells usually near the lower branches, tapering in 

 either direction so as to resemble a spindle, more or less. The 

 swelling may be irregular and extend into the branches. The 

 growth begins to look stunted and the trees do not branch 

 freely. 



Usually in May or June yellow bunches are discernible on the 

 eruptions of the swollen parts and when mature set free orange 

 colored spores which are carried to other plants. 



This disease can not live on pine alone, but requires a second 

 host plant for a part of its life history. This second host must 

 be the currant or gooseberry, and unless the spores liberated 

 from the pine reach one of these plants, they cannot develop. 

 After reaching the leaves of one of these plants they start 

 growth and soon develop so-called summer spores on the under 

 sides of the leaves. These spread to other plants and so are 

 rapidly increased. After a month or so these cease to form 

 and other "winter" spores are developed. These spores will 

 not start growth again on the currant or gooseberry but must 

 be blown to a white pine. Thus the disease alternates from 

 pine to the groseilles and back to pine and so on. 



Young pines are usually killed with the development of the 

 first spores, ultimately at any rate. 



Older trees lose their new growth and may be killed outright. 



Should this disease reach our white pine, it would be 

 about impossible to save them and thousands of dollars worth 

 of timber would be destroyed. 



If anything suspicious is noted on this kind of tree, notify 

 the Department at the earliest moment. 



