8 



Blister Canker (Nummularia discreta Tul.) 

 A form of canker caused by the above-named fungus has 

 been observed in apple-growing regions of the Mississippi 

 vallev, but never in our section. This canker is characterized 

 by a black, rough, more or less charred appearance of the 

 bark on the older parts of the tree. On the surface of the 

 diseased areas may be seen circular dots or fruiting bodies 

 which are regarded as the most characteristic feature of the 

 disease. We have recently seen a few apple trees in this 

 section which seem to show the symptoms of this canker, but 

 the specific fungus was not observed. It is believed to be a 

 wound fungus. 



Appi>e Rust (Gymnosporangium maceopus Lk.). 



This species of fungus is believed to be the principal cause 

 of the apple rust in our section, one of the stages being found 

 on the pear and quince. It is also believed to produce the 

 so-called cedar apple on out common pasture juniper (Juni- 

 perus virginiana) . Its appearance during the past few years 

 has seemed to coincide with a general epidemic of rust 

 throughout the country, and although it had been unusually 

 rare on apples for many years in Massachusetts up to the 

 past three or four years, since then it has often been found 

 on foliage, and sometimes on the fruit. It is more common 

 on neglected trees than in a scientifically managed orchard. 



All rusts are difficult to control by spraying, but besides 

 the general treatment which apple trees should receive each 

 year, sanitary methods of culture should be practiced. 



Apple Scab (Venturta Pomi (Fr.) Wint,). 



A disease known as apple scab has been present in Mas- 

 sachusetts for many years, afi:'ecting both the leaves and fruit 

 and occasionally the twigs of several varieties of apple trees, 

 — in this Stale, more particularly the light-colored varieties. 

 Fortunately, the disease seldom assumes a severe form here. 

 It is more commonly found on the foliage than on the fruit, 

 especially in unsprayed, neglected orchards. It is character- 



