Suggestions ap.out Spraying. 261 



and it can be applied only to the trunks and larger limbs except when 

 the plants are thoroughly dormant. Kerosene is more easily applied 

 than whale-oil soap. It is of uniform strength, while the qualities of 

 whale-oil soap are quite uncertain. 



Pure kerosene has been recommended as a specific for this pest, and 

 doubtless it is, but its effects upon the host plant are less certain. It 

 is a well known fact that pure kerosene may be used on some plants 

 with perfect safety and it has been so used on some of the orchard- 

 hosts of this scale with apparent impunity ; it has also been used with 

 decidedly fatal results to the host. 



Natural enemies of ihe scale. — There are several of these, to which 

 only a passing reference can here be made. 



There are several insects which feed more or less upon it and a 

 number of fungi are its parasites, but its most destructive enemies, both 

 insect and fungous, are natives of southern or wann climates and it is 

 doubtful if these can be of much use in combating it in the north. 

 The most destructive enemy, apparently, is a fungus {Spliaeros tilde 

 coccopliila) which is found in Florida. Its utiHty as a destroying agent 

 has been studied and reported by Rolfs of the Florida Experiment 

 Station.* 



In the first part of this bulletin an attempt was made to point out 

 the necessity of being thorough in the work of spraying. We would 

 again emphasize the close connection which exists between thorough- 

 ness and success. As important as this is in all ordinary spraying, it 

 is even more so in attempting to combat the San Jose scale. The 

 insect is so small and often attached to uneven places on the bark, 

 particularly if the bark is rough and full of little crevices, that it is 

 only with the utmost care that even a lar^e percentage of the scales 

 can be reached by the spray, to say nothing of exterminating the foe, 

 and reproduction takes place with such phenomenal rapidity that one 

 scale will soon give rise to thousands. 



*Bull. 41, Fla. Exp. Sta. 



