APPLE DISEASES 



451 



by the proper use of Bordeaux mixture, 

 the remedy recommended at the end of 

 this paragraph. While a certain number 

 of applications are recommended, more 

 will have to be given if the season is 

 wet. The object should be to keep the 

 trees covered with the mixture from 

 the first until the last spraying. If the 

 mixture is washed off the tree the dis- 

 ease will have an opportunity of devel- 

 oping and it is difficult to check it, if 

 it begins to spread. 



Kpniedy 



■ Spray with copper sulphate solution 

 (one pound copper sulphate to 25 gal- 

 lons water) or with Bordeaux mixture 

 before the buds start, or when they be- 

 gin to break; and with Bordeaux mix- 

 ture, just before blossoms open; soon 

 after blossoms fall and two or three 

 times after at intervals of from 10 to 15 

 days. The first three sprayings are the 



most important. „, „ ht 



W. T. M.^cotx, 



Ottawa. Canada- 

 Blight 

 BaciUus amylovorus (Burrill) De Toni. 

 FiKE Blight, Peab Blight. Twig 

 Blight. See under Pear. 



Blister Canker 



Xum7nularia discreta Tul. 

 The disease is sometimes known as 

 "Illinois Canker." since it was first ob- 

 served as particularly destructive in that 

 state. It seems to be less destructive 

 in New England than the black rot 

 and European cankers. It has a char- 

 acteristic appearance that readily dis- 

 tinguishes it from either of these dis- 

 eases. (See Fig. 1.) It is usually found 

 on the larger limbs, and sometimes at- 

 tacks the trunk. Old cankers are often 

 a foot or more in length. The fungus 

 attacks the wood as well as the bark. 

 In the early stages of the disease the 

 bark is brown and slightly sunken and 

 usually set off from the healthy bark by 

 a distinct boundary. As the season ad- 

 vances circular fungous masses known 

 as stromata develop on the diseased area. 

 They are formed beneath the bark, but 

 soon break through to the surface, fur- 

 nishing the most characteristic feature 



Fig. 1. Blister Canker of Apple, The liai-k has 

 been removed from the upper portion show- 

 ing the circular markings produced in the 

 wood. 



of the disease. The stromata are firmly 

 fastened to the wood by means of a hard 

 ring of fungous tissue, so that they re- 

 main attached to it even after the bark 

 has fallen away. Summer spores are 

 produced on the surface of the stroma. 

 Later in the season, numerous flask- 

 shaped perithecia are formed within the 

 stroma, but opening on its surface. These 

 produce many club-shaped asci, each con- 

 taining eight spherical, brown spores. 



Treatment 



The fungus seems to be dependent 

 upon wounds for entrance to the host 

 tissue. The best method of treatment 

 is found in avoiding unnecessary in- 

 juries to the tree and in the proper care 

 of all wounds. All cankered limbs should 

 be destroyed. Ch.\rles Brooks, 



Durham, X. H. 



Blos.som Blight. See Blight under 

 Pear. 



Blotch 

 PhyUosticta soUtaria E. & E. 



The blotch is caused by a fungus 

 which lives parasitically upon the fruit, 

 twigs and leaves of the apple. 



