﻿24 



BULLETIN 1371_, U. S. DEPARTMENT OF AGRICULTURE 



EXPERIMENTS IN 1923 " 



The tests with dry barium-sulphur No. 3 were made at Stuart, Va., 

 and Canton, Miss. The results of these experiments are shown in 

 Tables 23 and 24. 



Table 23. — Results of tests with dry barium-sulphur sprays against the Sa7i Jose 

 scale on apple trees at Stuart, Va., in 1923 



Material used 



Barium sulphur No. 3. 

 Do - 



Liquid lime-sulphur ' 

 Check 



Quantity 



in 50 



gallons 



of spray 



Pounds 

 14 

 31 



Gallons 

 6.66 



Hibernating scale 



Dead 



Per cent 

 54.9 

 79.6 



97.0 

 22.7 



Control 



Per cent 

 41.7 

 73.6 



Infestation of young scale on 

 80 linear inches of new 

 wood (first generation) 



Number 

 of scales 



233 



148 



51 

 804 



Average 

 per inch 



2.91 

 1.85 



.64 

 10.05 



Percent- 

 age of 

 check 



28.9 

 18.4 



6.3 



1 Baumg 31.8°. 



The tests reported in Table 23, although made where the scale 

 was not very abundant, show the same lack of control, in spite of 

 the fact that, in one case, the barium-sulphur was used at the rate of 

 31 pounds to 50 gallons. Even this strength showed 22.5 per cent 

 less control on the hibernating scale and almost three times as many 

 young scales per inch when compared with the trees sprayed with 

 liquid hme-sulphur. 



Table 24. — Results of tests with dry barium-sulphur sprays against the San Jose scale 

 on peach trees at Canton, Miss., in 1923 





Quan- 

 tity in 

 50 gal- 

 lons of 

 spray 



Hibernating 

 scale 



Infestation of young scale on 80 linear inches of 

 new wood 



Material used 



First generation 



Second generation 





Dead 



Con- 

 trol 



Num- 

 ber of 

 scales 



Aver- 

 age per 

 inch 



Per- 

 cent- 

 age of 

 check 



Num- 

 ber of 



scales 



Aver- 

 age per 

 inch 



Per- 

 cent- 

 age of 

 check 



Barium-sulphur No. 3 



Do 



Pounds 

 14 

 31 



Gallons 

 6.66 



Per cent 

 56.7 

 71.4 



96.4 

 16.2 



Per cent 

 48.3 

 65.9 



95.7 



298 

 173 



39 

 1,022 



3.73 

 2.16 



.49 

 12.78 



29.2 

 17 



3.8 



468 

 231 



92 

 1,262 



5.85 

 2.89 



1.15 



15.78 



37.1 

 18.3 



Liquid lime-sulphur' 



Check 



7.3 









I Baume 31.8° 



The experiments in Canton, Miss., show the same lack of control 

 by barium-sulphur that was noted in previous tests. A strength of 

 31 pounds to 50 gallons gave a control of only 65.9 per cent on the 

 hibernating scales and allowed 4.5 times as many scales to settle on 

 the new wood as did the standard hquid lime-sulphur. 



18 Details of these experiments are given on pages 11 and 12. 



