October, '15] 



MELAXDER: SAX JOSE SCALE 



479 



until the middle of March and is continued into April, in some 

 instances deferred even until the trees are coming into leaf. Accord- 

 ingly, in order to obtain critical evidence bearing on this problem cer- 

 tain treatments were repeated on March 26, nineteen days after the 

 original tests were given. While the information they afford is not 

 conclusive, these tests indicate that later sprayings are much less 

 dependable than the earlier. The insects die in both cases at about 

 the same rate during the weeks immediately follo^^ng the spraying, 

 but when growth sets in there is a larger proportion of survivors in 

 the case of late spraying and these indi\dduals, no longer subject to 

 the action of the weathered spra^^, are able to negative the effects of 

 the spraying. The following tabulation shows what a large propor- 

 tion of scales are able to withstand a late application at North Yakima: 



21 days 12 days 29 days 



Sulphur-lime, 3° 28% 22% 26% 



Sulphur-lime, 2° 29 47 49 



Sulphur-soda, 3° 41 38 48 



Sulphur-soda, 2° 44 43 43 



Walla Walla 



Sulphur-lime has been used at Walla Walla probably as long as 

 anywhere in the northwest and if its influence is selective, hardy scales 

 should be expected to occur here. The tests with the same materials 

 that were used at the other stations gave uniformly poor results in 

 the case of sulphur sprays but the oil spray again afforded complete 

 and rapid extermination. It should be noted that by the time of the 

 final examination the male insects had long since emerged and the 

 females were gravid with young. 



20 days 15 days 20 days 



Sulphur-Hme, 5° 49% 35% 34% 



Sulphur-Kme, 3° 48 28 27 



Sulphur-Hme, 2° 57 37 27 



Sulphur-soda, 3° 36 28 32 



Sulphur-soda, 2° 53 42 36 



on, 5% 1 0 0 



Check 92 89 72 



Clakkston 



Clarkston at the present time is probably as badly over-ridden with 

 San Jose scale as any fruit district. The destruction wrought by 

 this insect is almost inconceivable : cherry and peach trees are dying 

 throughout the lower part of the flat and the apple and pear crop is 

 so badly specked with scale as to be unmarketable. Conditions in 

 the adjacent district, Vineland, higher in elevation, are not nearly 



