tJOO Report of the Depautmkxt of Entomology of the 



individual specimens will be alive. Again, the percentage of 

 living scale-insects will vary not onl}' on the part of the tree 

 upon which they occur but also with the season of the 3'ear. 



CONDITION BEFORE TREATMENT. 



The following table gives approximately the condition of the 

 San Jos6 scale-insect on peach in March, 1001, prior to treat- 

 ment. The percentages were obtained by taking the infested 

 branches into the laboratory and making a microscopic examina- 

 tion of all the specimens. The branches were taken from dif- 

 ferent trees: 



Table VII. — San Jose Scale on Peach, March, 1901. 



Living specimens on first branch. .. . 

 Living specimens on second branch . 

 Living specimens on third branch... 



« • 



Average 24.3 59.6 42. 



CONDITION AFTER TREATMENT. 



Under tents. — (1) In the small orchard, November 20, 1900, four 

 plums showed a few living specimens of the scale-insects on new 

 wood. Three of the trees were badly infested before treatment; 

 on the other, specimens were numerous at time of treatment. 

 These trees were fumigated April 13th. As near as could be 

 estimated for tents, If to 2 ozs. of potassium cyanide per 100 

 cu. ft. were used for periods varying from 35 to 60 minutes. 

 One cherry, treated April 14th with over 2 ozs. per 100 cu. ft. for 

 TO minutes has living specimens on new wood. Specimens were 

 numerous before treatment. 



It is a marked fact that as late as December 7, 1901, the in- 

 crease of specimens on the above trees has been so slow that it 

 is still a hard matter to find them. 



(2) In the large orchard, living specimens of the insects were 

 found on treated trees in one instance, but as only part of the 

 orchard was treated there was a chance for the insects to be 

 transferred from untreated to treated trees thus making it im- 



