]>E1'AUTMEXT OF AGRICULTURE. 



the disease is probably best known and most directly injurious, such fruit being 

 much reduced iu market value. The spots are circular, or nearly so. and dark olive 

 to black in colour. The dried remains of the cuticle are often visible around the 

 margin of the spot, ('racking of the fruit at the affected spots often follows and 

 may lead to the formation of large cracks right across the fruit if the spots are 

 numerous. When the infection takes place early and is at all severe, it may cause 

 serious malformation nnd stunting of the fruit. Twig-infK-tion is not common with 

 us. Throughout the season con id i a are formed on the spots, and new infections may 

 take place if the conditions are suitable. On stored fruit old infections may 

 increase in size and new ones may also occur. Owing to the removal of the protect- 

 ing cuticle at the affected spots, such apples shrivel sooner than sound ones, and 

 rot-fungi, particularly the pink-rot (<.'( i>ltalotli>< <m, . can readily obtain an 



entrance. 



After the affected leaves have fallen the 

 fungus in them undergoes a further develop- 

 ment during the winter months, giving rise 

 to spores of a different kind i n*<:>ixii'>r< * \. 

 are first liberated about the time 

 when the 1 !ssoms are opening, and over 

 a period of perhaps three or four weeks. 

 The first infectious each season come almost 

 entirely from this source. 



trol. This is a typical case of a 

 96 controllable by preventive spraying. 

 The spores germinate and produce infection 

 throughout the growing season if moisture 

 conditions are favourable. To prevent this 

 it is necessary that all susceptible parts be 

 kept covered with a suitable fungicide as 

 long as climatic conditions are such as to 

 favour new infections. Owing to the differ- 

 ence between one season and another, one 

 of the chief difficulties is to judge correctly 

 the number and times of application of the 

 sprayings required ; two sprayings may be 

 sufficient in one season where three or four 

 might be required during the next. Bor- 

 deaux mixture is an effective spray material 

 as far as the control of the disease goes. 

 but often causes serious russeting of the 

 fruit, and for this reason has been largely 

 superseded by lime-sulphur for sprayings 

 after blossoming - time. Since infection 

 comes from the fallen leaves about blos- 

 soming-rime, the " dormant " spray with 

 lime-sulphur has little effect in controlling 

 scab, although it may destroy a few over- 

 wintering couidia. The important sprays 

 are as follows : First, when the blossoms 

 are well separated in the cluster, showing 

 pink, but still unopened. ' Lime-sulphur 

 solution 1 to 30 or Bordeaux mixture 

 4-4-40 may be used at this stage, as there 

 is little danger of russeting. Second, when 

 last petals are falling, with lime-sulphur 

 1 to 30 or 1 to 40, according to circum- 



Kitr. J. Apples affected with scab. No. li 

 shows the skin of the apple, split off from 

 the underlying tissue, persisting round the 

 edge of the fungus-spot. No. o shows the 

 cracking which oft^n supervenes. Both 3 

 and 4 show malformation as a result of 

 scab-infection. 



