BULLETIN OF THE 



No. 197 



Contribution from the Bureau of Entomology, L. O. Howard, Chief. $, 



March 31, 1915. 



HOMEMADE LIME-SULPHUR CONCENTRATE. 



By E. W. Scott, 

 Entomological Assistant, Deciduous- Fruit Insect Investigations. 



During the past few years much attention has been given by 

 investigators to the home preparation of lime-sulphur concentrate 

 and also to an inquiry into the chemical reactions involved, as affect- 

 ing the conditions under which the work should be done. These 

 investigations have had for their purpose the encouragement of 

 orchardists in the preparation of concentrates for their own use, or 

 for the use of the neighborhood. The success of these efforts is shown 

 by the fact that many fruit growers now prepare their own lime- 

 sulphur concentrates, thus effecting a material saving over the cost 

 of the commercial article. 



Orchardists, as a rule, are not able consistently to obtain a product 

 of uniform density, even though the same formula be employed and 

 the work be accomplished as nearly as possible in an identical manner 

 for the different batches. This defect, however, is really of little 

 importance, since it is easy to test the density of the concentrate and 

 make dilutions in conformity with the purpose for which it is to be 

 used. 



During the past few years the Bureau of Entomology has given 

 attention to the making of lime-sulphur concentrates in connection 

 with work in deciduous-fruit insect investigations. No particular 

 chemical study was planned in connection with these cooking tests, 

 as it was merely desired to know the degree of density and percentage 

 of the " sludge" which would result by the employment of different 

 formulas. The cooking tests for the most part were made at lime- 

 sulphur plants operated by orchardists, or by individuals who sup- 

 plied the concentrate to orchardists in the immediate territory. 



EXPERIMENTS AT BERRYVILLE, VA. 



Six experiments were conducted at a small plant at Berryville, 

 Va. This plant consisted of a 12-horsepower boiler and two 150- 

 gallon cooking vessels. The cooking was done by steam which was 



Note.— Describes experiments in making lime-sulphur concentrates and gives the most satisfactory 

 formulas. Of interest to all practicing spraying in insecticide work. 

 81647*— Bull. 107—15 



