554 ANNUAL REPORT OF THE Off. Doc. 



Tlie Sail Jose Scale was said to be several years a^^o the most seri- 

 ous pest affecting the nursery and orchard interests of the country; 

 it is so to-day notwithstanding all that has been done to check its 

 spread. 



If we have found applications that will save the orchard trees 

 and their fruit, it must be borne in mind that those applications 

 must be made use of at the right time and in the right manner. The 

 process is somewhat expensive and is voluntarily used only by those 

 who are progressive fruit growers, and those who have something 

 to gain by their efforts. Others must be forced to care for their 

 trees to abate the nuisance and prevent the spread of scale on prem- 

 ises adjoining. 



San Jos6 Scale commence breeding in New York State about 

 June 20; and from that time until freezing weather, the young larvae 

 can be found upon the trees. It is known that a single female scale 

 giving birth about June 20, to many young, the most of which com- 

 mence breeding within a month and which are followed by other 

 generations soon, so that within the breeding season, the progeny 

 numbers millions. This condition suggests the desirability of an 

 early inspection of the nurseries to discover and destroy the first 

 females; it also emphasizes the importance of several inspections 

 during the season. With many acres of trees covered with leaves 

 no single inspection will suffice and no inspector can be sure that no 

 scale is present. Nurseries suspected of infestation should have the 

 attention of an inspector many times in a season. Every infested 

 tree within the nursery and all infested trees in the vicinity should 

 be destroyed. 



The fact that thorough inspection seems the only way to prevent 

 spread of scale within the nursery it is not certain that every scale 

 will be seen and destroyed. Fumigation with hydrocyanic acid gas 

 is the only method in use at the present time to set a seal of rea- 

 sonable certainty that no live scales shall pass by shipment from 

 the nursery to the orchard. 



The major portion of the evidence in possession of the Department 

 shows that when nursery stock is mature or well ripened, that it 

 may be fumigated once or many times with h^^drocyanic acid gas, 

 using two or three times as much cyanide of potassium as is nec- 

 essary to kill the scales, without injury to the trees. When fumiga- 

 tion is properly done with chemicals of known purity in a house 

 suitably constructed, on trees that are ripe and dormant, dry and 

 free from mud, there is no evidence to show that injury will result 

 to the trees and no live scales will pass on the nursery stock. Em- 

 phasis must be laid on the point of proper fumigation in all its de- 

 tails, otherwise good results cannot be obtained, and disaster or loss 

 mav occur. 



