452 Diseases of Economic Plants 



or of a lasting nature. The injury consists of irregular brown 

 spotting, especially where the spray accumulates immediately 

 after its application. If, however, the leaves have been 

 injured by apple-scab, previous to the application of the 

 spray, the damage done to the foliage is very serious. There 

 is no marked degree of varietal susceptibility with apples. 

 The injury occurs soon after the spray has been applied, not, 

 as in the case of Bordeaux injury, at a period which may be 

 long after its application. The foliage is least susceptible to 

 injury soon after it has unfolded. Talbert states that the 

 dormant spray consisting of commercial lime-sulfur, testing 

 33° Baume, may be applied to apple trees diluted 1 to 7 or 

 1 to 8 after growth starts and until the trees begin to bloom, 

 without material injury to the leaves or flower buds. 

 This is a much higher concentration than is usually used 

 when the trees are in foliage. 



Lime-sulfur injury to the fruit occurs occasionally, as the 

 result of drenching. It is generally conceded that injury 

 to the fruit occurs if lime-sulfur is used in hot weather, 

 after the fruit has developed to approximately the size at 

 which it becomes relatively immune to Bordeaux injury. 

 From this stage onward, Bordeaux mixture is again used, 

 regardless of the foliage injury produced. Lime-sulfur injury 

 may, however, result from the application made just after 

 the petals fall or those just following. 



Spraying Apparatus 



Whether for spraying a small garden or a large commercial 

 orchard proper apparatus is needed. 



The chief types of pumps are briefly mentioned be- 

 low. 



Bucket pumps. — These pumps are suited for use in the 

 garden; to spray the bushes or a few small fruit trees in the 

 yard. The fact that they may be used in any ordinary 

 bucket or pail gives them an advantage over some of the 

 other outfits. By the attachment of a foot rest which ex- 



