36 
BULLETIN/ 278, U. S. DEPARTMENT OF AGRIClTLTTLRE. 
sprayed at each, end of the orchard and also in central sections as a 
basis for comparison with the sprayed. The spray materials were 
applied while the trees were dormant, April 10, 11, and 13, nsing a 
small power outfit. 
To determine the efficacy of the scale insecticides two methods 
were employed: first, the examination of the scale-infested twigs for 
dead and live scales by means of the binocular microscope. This 
method proved to be anything but satisfactory. The second and 
better method of determining results was the examination of the 
fruit for scale which crawled thereon. All of the dropped fruit from 
the count trees was picked up and examined weekly throughout the 
season. The picked fruit at harvest time was also examined. In 
Table XIX will be found the results according to variety. Table XX 
is a commercial summary of Table XIX. 
As will be noted in Table XX (commercial summary), the percentage 
of fruit (all varieties) free from scale and that with a light infestation 
has been combined for a comparison with the percentage of fruit with 
an infestation medium and heavy. The scale upon the fruit classified 
as lightly infested was usually found more or less concealed in the 
calyx cavity and, therefore, did not mar the appearance of the fruit 
for market. Furthermore, a large percentage of the fruit lightly 
infested had but two or three scales per fruit. 
The fruit with a medium and heavy scale infestation was unmarket- 
able. Frequently the fruit in the heavy scale infestation class was 
blood red in appearance and would average 500 to 1,000 scales per 
fruit. This condition was chiefly found on the unsprayed trees, 
whose foliage was likewise heavily infested with the scale insects. 
Table XIX. — San Jose scale insecticide investigations, Benton Harbor, Mich.. 1914. 
Plat. 
I 
II 
III 
IV 
V 
VI 
VII 
VIII 
IX 
Name and dilution. 
Lime-sulphur, 1-7 
(lj Commercial sodium sul- 
phid, 12.5 pounds-50 
Caustic potash, 11 pounds-i- 
sulphur, 12.5 pounds-50. .. 
(2) Commercial sodium sul- 
phid, 12.5 pounds-50 
Caustic soda. 11 pounds— sul- 
phur, 12.5 pounds-50 
Lime-sulphur. 1-7— nitrate of 
soda, 50 pounds-50 
Caustic soda, 15 pounds-fsul- 
phur, 17.1 pounds-50 
Caustic potash, 15 pounds -i- 
sulphur, 17.1 pounds-50. . . 
Check— unsprayed 
Number of 
count trees. 
Number of fruits 
3 1,841 
1 1,717 
2 1,008 
.; o 
1,865 
946 
1,531 
1,116 
5,100 
242 
94 
191 
238 
14 
113 
263 
Per cent of fruit. 
Free from scale. 
389 75. 667 53. 201 51. 241 68. 637 
I 
10 59. 059 41. 505 20. 215 90. 000 
I I 
1, 522 25. 101 30. S92 39. 490 
38.622 32.774 
I 
78. 709 34. 559 41. 430 
15 76.2S9 50. 445 SO. 000 
521 89. S77 51. 750 70. 194 54. 892 
0(89. 247178. 771 151.716 
299 1,825 4,474 52.595 25.420 S.056 6.S41 
it 
