OBSCURE SCALE ON THE PECAN AND ITS CONTROL 



11 



generation each year, and the numbers are further considerably 

 reduced by natural agencies; (7) miscible oils varied widely in effec- 

 tiveness, giving generally poorer results than the 4-percent lubri- 

 cating-oil emulsions but considerably better results than those given 

 by the 2-percent emulsions. While far from satisfactory, they will, 

 with the assistance of natural agencies of control, hold a scale infesta- 

 tion in check; (8) liquid lime-sulphur was not effective. 



Table 1. — Results of spray experiments on the obscure scale on pecan trees, Shreve- 



port, La., 1930-81 



[Approximately 1,000 scales were examined in each test except no. 22, in which approximately 3,000 scales 



were examined] 



Test 

 no. 



Material used l 



Oil 1 3. 

 ....do. 



do. 



Oil2 3 . 

 ..._do. 

 .— . do. 

 Oil 6 3. 



do. 



____do. 



Oill«— . 



do— . 



_.„do— . 



Oil 2 4.... 

 ____do— 



do— . 



Oil 6*—. 



do.— 



....do— 



Oil 7 



Oil 4 



Lime-sulphur 



Unsprayed check. 



Oil? 



Oil6* 



do 3 



Unsprayed check. 

 Oil 6 * 



Oil per- 

 centage 

 or parts 



of 

 stock 

 solu- 

 tion to 

 parts of 

 water 



2 

 4 

 6 

 2 

 4 

 6 

 2 

 4 

 6 

 2 

 4 

 6 

 2 

 4 

 6 

 2 

 • 4 

 6 

 1-15 

 1-15 

 1-7 



1-15 

 4 

 4 



Spray applied 

 December 1930 



Scales dead 



Per- 

 cent 

 40.5 

 93.9 

 98.4 

 63.5 

 91.1 

 100.0 

 68.2 

 88.3 

 96.3 

 46.3 

 96.6 

 96.9 

 45.0 

 95.8 

 100.0 

 46.6 

 91.9 

 99.2 

 92.9 

 93.8 

 26.0 

 17.2 

 27.7 

 77.3 

 72.9 

 20.3 



3 en 



T3 <o 



Per- 

 cent 

 10.1 

 68.1 

 84.5 

 17.2 

 67.5 

 87.1 



9.0 

 33.0 

 77.6 

 10.8 

 78.5 

 92.4 

 10.7 

 75.6 

 94.3 



9.6 

 72.7 

 88.9 

 65.6 

 56.5 



6.7 



6.5 

 10.3 

 44.0 

 28. 



2.3 



Per- 

 cent 

 16.3 

 73 



87.0 

 26.0 

 72.2 

 89.3 

 21.8 

 45.6 

 81.7 

 18.8 

 83.4 

 93.0 

 17.9 

 78.5 

 94.9 

 18.3 

 69.2 

 90.2 

 69.1 

 63.6 

 11.2 

 8.4 

 14.1 

 50.2 

 41.8 

 4 



Per- 

 cent 

 8.6 

 71.5 

 85.8 

 19.2 

 69.6 

 88.3 

 14.6 

 40.6 

 80.0 

 11.4 

 81.9 

 92.4 

 10.4 

 76.5 

 94.4 

 10.8 

 66.4 

 89.3 

 66.3 

 60.3 

 3.1 



47.i 



Spray applied 

 February 1931 



Scales dead 



Per- 

 cent 

 59.0 

 75.2 

 90.4 

 72.6 

 95.6 

 98.5 

 68.2 

 90.2 

 97.7 

 58.5 

 97.1 

 99.1 

 68.0 

 95.3 

 90.4 

 47.8 

 92.5 

 100.0 

 65.0 

 74.8 

 45.4 

 14.0 

 46.4 

 58.6 

 67.8 

 12.7 



Per- 

 cent 



24.8 

 48.1 

 72.8 

 26.6 

 72.9 

 74.8 

 21.1 

 63.8 

 77.6 

 26.1 

 78.0 

 97.7 

 26.9 

 79.1 

 86.5 

 14.5 

 81.7 

 93.2 

 29.7 

 36.8 

 18.6 

 10.8 

 15.3 

 22.6 

 22.8 

 4.7 



Per- 

 cent 

 30.3 

 51.6 

 75.9 

 34.7 

 76.5 

 80.7 

 29.3 

 60.6 

 83, 

 29.9 

 81.9 

 98.0 

 35.4 

 81.8 

 87.4 

 20.7 

 83.4 

 94.1 

 39.1 

 45.1 

 27.9 

 11.6 

 23.0 

 31.6 

 36.5 

 7.2 



Per- 

 cent 

 21.2 

 45.2 

 72.7 

 26.1 

 73.4 

 78.2 

 20.0 

 55.4 

 81.4 

 20.7 

 79.5 

 97.7 

 26.9 

 79.4 

 85.7 

 10.3 

 81.2 

 93.3 

 31.1 

 37.9 

 18.4 



"l7."6 



26.3 

 31.6 



Spray applied 



March-April 



1931 



Scales 



Per- 

 cent 

 52.5 

 60.5 

 87.5 

 60.4 

 73.0 

 95.3 

 54.4 

 87.1 

 92.3 

 50.0 

 67.4 

 88.8 

 53.2 

 90.6 

 94.4 

 52.6 

 69.0 

 94. 

 41.2 

 73.2 

 61.2 

 23.4 

 46.5 

 73.1 

 60.6 

 28.4 

 96.1 



Per- 

 cent 

 36.5 

 66.1 

 88.9 

 45.1 

 58.6 

 89.7 

 27.7 

 72.3 

 86.2 

 33.8 

 50.3 

 87.3 



79.4 

 87.3 

 32.9 

 57.5 

 88.7 

 38.0 

 73.0 

 41.3 

 17.3 

 41.4 

 57.1 

 59.0 

 15.1 

 97.4 



Per- 

 cent 

 38.0 

 67.2 

 88.8 

 45.9 

 59.5 

 90.1 

 29.5 

 73.2 

 86.5 

 35.2 

 51.1 

 87.4 



28.6 30.5 



80.1 

 87.8 

 34.8 

 58.5 

 89.2 

 38.3 

 73.0 

 43.0 

 17.8 

 42.6 

 61.6 

 59.4 

 18.7 

 97.2 



Per- 

 cent 

 24.6 

 60.1 

 86.4 

 34.2 

 50.7 

 88.0 

 14.2 

 67.4 

 83.6 

 21.2 

 40.5 

 84.7 

 15.4 

 75.8 

 85.2 

 20.7 

 49.5 

 86.9 

 24.9 

 67.2 

 30.7 



29.~4 



52.8 

 50.1 



1 For characteristics of oils used, see table 6. 



2 Tests 1-22, inclusive, in orchard no. 1, the spray applied with a hand-pumped barrel sprayer. 

 23-27 in orchard no. 2, the spray applied with a power sprayer. 



3 Emulsified according to formula no. 1 (p. 17). 



4 Emulsified according to formula no. 2 (p. 17). 



Tests 



In the tests reported in table 1 some injury resulted to the trees 

 that were sprayed in the first orchard, this injury being confined for 

 the most part to those tests in which the lubricating-oil emulsions 

 were applied at the 6-percent dilution. It was most serious in the 

 December application, less serious in the February application, and 

 absent in the March-April application, There was no noticeable 



