1774 



ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 



Appearance of the Diseased Canes 



Although the cane blight fungus is 

 found to attack the fruiting canes most 

 seriously, it also attacks young canes 

 during the first season's growth and de- 

 stroys them. In either case the whole 

 cane may be involved, and generally in 

 very susceptible varieties, such as black- 

 caps, the canes wilt and die down to the 

 crown. To the casual observer, the leaves 

 first begin to show a sickly yellow color, 

 later becoming wilted and brown. In 

 blackcaps the first, or early ripening ber- 

 ries, may be gathered, but as a rule the 

 canes wilt so quickly in a severe case of 

 the blight that the crop becomes a total 

 loss. 



Conditions ^Necessary for Infection 



Owing to the fact that the blackberry 

 and its related species are grown in rich 

 soil where irrigation is practiced, the 

 conditions for continuous infection dur- 

 ing the summer season are always pres- 

 ent. At this time ripe spores capable of 

 immediate germination are being pro- 

 duced in countless numbers, and some of 

 the canes have a smutty appearance due 

 to the large number of spores which have 

 exuded from the pustules found on the 

 diseased canes. These spores may be 

 transferred in many ways to healthy 

 canes. It may be seen, therefore, that 

 this season's young canes which are to 

 be left for next year's crop may be dis- 

 eased before the dormant season begins. 

 There is no doubt that infection may also 

 take place during the dormant season, 

 that is, after the leaves have fallen from 

 the canes. Owing to the mild winter 

 weather in Rogue River valley there is no 

 doubt that the fungus may continue its 

 activity during the winter. 



Control Measures 



It has been stated that the only prac- 

 tical method of preventing the disease is 

 to obtain healthy plants at the outset, 

 and to avoid planting where raspberries 

 or other related species have been grown. 

 It is also advised to remove and burn 

 old canes as promptly as possible before 

 the leaves fall. Where the disease has 

 become very serious all the canes should 



be cut close to the crown, and the ground 

 carefully cleaned of all rubbish, which 

 should be burned. The soil may then be 

 drawn away from the crowns, which 

 should be sprayed with a 5-5-50 Bordeaux 

 before the winter rains begin. Where 

 the disease has not become serious all 

 old canes, and particularly the diseased 



Fig. 2. Raspberry Cane Bligrht. Badly dis- 

 eased cane of Gregg blackcap. Note the 

 small pustules caused by the fungus at a 

 and &. These pustules contain the spores 

 of the fungus. 



ones, should be cut off close to the crown 

 and the remaining canes sprayed very 

 thoroughly with Bordeaux. In spraying, 

 it should not be considered wasting ma- 

 terial to spray the ground about the 

 crowns. 



Spring and Summer Spraying 



A thorough application of Bordeaux 

 mixture should be given the canes in the 

 spring before the leaves appear. This is 

 done in order to kill any spores which 

 might have escaped destruction by spray- 

 ing in the fall. When the leaves are well 

 out and the young shoots are six inches 

 in height a second application of 5-5-50 

 Bordeaux should be made. A third appli- 



