﻿UNITED STATES DEPARTMENT OF AGRICULTURE 



DEPARTMENT BULLETIN No. 1371 



Washington, D. C. 



January, 1926 



EFFECTIVENESS AGAINST THE SAN JOSE SCALE OF THE DRY 

 SUBSTITUTES FOR LIQUID LIME-SULPHUR 



By W. S. Abbott, Entomologist, and Julian J. Ctjlver, Assistant Entomologist, 

 Enforcement of the Insecticide Act, Bureau of Entomology, and W. J. Morgan, 

 Associate Chemist, Insecticide and Fungicide Laboratory, Miscellaneous Division, 

 Bureau of Chemistry 



CONTENTS 



Introduction -.. 1 



Materials used- 5 



Liquid lime^ulphur 5 



Records taken 5 



Percentage of control 6 



Dry calcium-sulphurs^ 6 



Dry sodium-sulphur compounds. 16 



Dry barium-sulphur compounds 21 



General summary 25 



Literature cited.. 25 



INTRODUCTION 



Several dry substitutes for liquid lime-sulphur have been on the 

 market for a number of years, but their value as remedies against 

 the San Jose scale (Aspidiotus ferniciosus Comstock) appears to be a 

 disputed point. A brief abstract of the published experiments cover- 

 ing this point is given below. 



The Arkansas station in 1921 (4, p. 13) ^ summarizes its work 

 with certain sprays against the San Jose scale by stating that barium- 

 sulphur,^ calcium-sulphur, and sodium-sulphur "while highly effective 

 in the season of 1921, were not so satisfactory during the two previous 

 years, and can not yet be given as strong a recommendation as lime- 

 sulphur." 



In the annual report of the State entomologist of Colorado for 

 1922 (25, y. 47) experiments with a dry calcium-sulphur used on plots 

 6, 7, and 8, respectively, at the rate of 49, 50, and 56 pounds to 200 

 gallons of water are summarized as follows: 



In the dry lime-sulphur plots, plot No. 8 shows a 3.08 per cent better kill than 

 plot No. 6. This difference might possibly be attributed to the nozzle holder as 

 different men did the work. Plot No. 7 shows perfect control, but the infesta- 

 tion was so light that a satisfactory count could not be made. 



The Connecticut station in 1923 {j5, p. 330) reports the following 

 results of experiments against the San Jose scale: Liquid lime-sulphur, 

 77.3 per cent killed; barium-sulphur, 72.6 per cent killed; calcium- 

 sulphur, 74.9 per cent killed. 



< Reference Is made by number (roman) to "Literature cited," pp. 25 and 26. 



» For wnvenioncc in discussion the substitutes for liquid lime-sulphur are referred to as calcium, sodium, 

 and barium sulphurs. 



582.M— 2Ct 1 1 



