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BULLETIN' 1371, U. S. DEPABTMENT OF AGRICULTURE 



In the experiments reported in Table 8 the dry Hme-sulphurs at the 

 rate of 15 pounds to 50 gallons of water gave an average control of 

 38.7 per cent, and at 26 and 27 pounds to 50 gallons an average con- 

 trol of 63.4 per cent as compared with 96.1 per cent for liquid hme- 

 sulphur. 



The average number of young scales per linear inch of new wood 

 for the same experiments was 3.5, 1.55, and 0.64. Although the 

 number of young scales found per inch of new wood was rather small, 

 it should be noted that the 15-pound treatment allowed 5.5 times as 

 .many scales to settle as did the liquid lime-sulphur; and the 26 and 27 

 pound treatments 2.4 times as many. 



PEACH TREES, 1923 



The same materials (see Table 7) were tested against the San Jose 

 •scale on peach trees at Canton, Miss., in the same orchard that was 

 used in 1922, although the infestation was not so heavy as that of the 

 previous season. From five to seven trees were used per plat, and 

 these were sprayed on February 14, using a barrel pump which main- 

 tained a pressure of 100 to 125 pounds with a rod and disk nozzle. 

 An average of 1 3^ gallons per tree was applied. 



The hibernating scales were counted on March 23 and the counts 

 of the first and second generations were made on June 27 and October 

 4. The results of these experiments are shown in Table 9. 



Table 9. — Results of tests against the San Jose scale on peach at Canton, Miss., 



in 1923 





Quan- 

 tity 

 in 50 



gallons 

 of 



spray 



Hibernating 

 scale 



Infestation of young scale on 80 linear inches 

 new wood 



Material used 



First generation 



Second generation 





Dead 



Con- 

 trol 



Total 

 scales 



Aver- 

 age per 

 inch 



Per- 

 centage 

 of check 



Total 

 scales 



Aver- 

 age per 

 inch 



Per- 

 centage 

 of check 



Dry lime-sulphur A 



Pounds 

 15 

 27 

 15 

 27 

 15 

 26 

 Gallons 



6.66 



0) 



Per cent 

 53.2 

 69.7 

 55.9 

 75.0 

 50.7 

 70.1 



96.4 

 16.2 



Per cent 

 44.2 

 63.8 

 47.4 

 70.2 

 41.2 

 64.3 



95.7 



215 

 157 

 206 

 151 

 242 

 136 



39 

 1,022 



2.69 

 1.96 

 2.58 

 1.89 

 3.03 

 1.70 



.49 

 12.78 



21.0 

 15.4 

 20.2 

 14.8 

 23.7 

 13.3 



3.8 



627 

 425 

 487 

 249 

 500 

 289 



92 

 1,262 



7.84 

 5.31 

 6.09 

 3.11 

 6.25 

 3.61 



1.15 

 15.78 



49.7 



Dry lime-sulphur B . 



33.7 

 38.6 



Dry lime-sulphur C 



19.7 

 39.6 



Liquid lime-sulphur 



22.9 

 7.3 



Check 









1 Untreated. 



When used on peach trees at the rate of 15 pounds to 50 gallons of 

 water the average control obtained with the dry materials was 44.27 

 per cent. When the strength was increased to 26 or 27 pounds the 

 control rose to 66.10 per cent, but tliis does not compare very favor- 

 ably with the 95.7 per cent control obtained with liquid lime-sulphur 

 concentrate. The 15-pound applications showed an average of 42.6 

 per cent and the 27-pound spray an average of 25.4 per cent as many 

 young scales of the second generation as were found on the untreated 

 check, which is 5.9 and 3.5 times as many as were present in the 

 liquid lime-sulphur plat. 



