1898.] PUBLIC DOCUMENT — No. 33. 61 



diseases. The trouble appears in the branches, sometimes 

 a whole limb of considerable size, but more often the smaller 

 terminal twigs, being affected. These portions of the tree 

 suddenly wilt and die, the leaves and young fruit turning 

 black and hanging to the branches, producing the character- 

 istic scorched appearance which gives the disease its name. 

 It spreads rapidly about an orchard and increases from year 

 to year, often involving the entire tree and causing its death 

 if left unrestricted. 



The cause of this trouble was long a matter of specula- 

 tion, but it is now known to be a species of bacteria which 

 gains access to the tissues of the tree and by its rapid 

 multiplication therein causes great destruction. This dis- 

 ease cannot be reached by spraying, and the only remedy 

 consists in severely cutting back all affected branches, or 

 whole trees if badly affected. All such prunings should 

 then be destroyed by burning. This cutting should be done 

 whenever the disease is observed, but is especially advisable 

 in the fall or late summer, when the trees should be care- 

 fully examined, to make sure that no diseased branches or 

 twigs are left to perpetuate the disease over winter. As 

 the disease affects the hawthorne (Crataegus), shad bush 

 (Amelanchier) and mountain ash (Pirus Americana), as 

 well as the cultivated fruits, it may spread from some of 

 these wild trees to the latter, unless care is taken to prevent 

 such contagion. It is not probable, however, that such in- 

 fection is ordinarily at all extensive. 



The Quince Rust. 



(^Oymnosporangiitm clavipes C. and P.) 

 The numerous inquiries which we have received during 

 the past season concerning this not uncommon trouble, as 

 well as our own observations, indicate that it has been un- 

 usually prevalent and destructive. The disease affects prin- 

 cipally the fruit, but also the young wood, causing distortion 

 and malformation in both cases. It is very conspicuous 

 upon the affected quinces in midsummer, both from their 

 distorted shape, and from the numerous white, tubular ex- 

 crescences appearing upon their surface. These excres- 



