﻿DKY SUBSTITUTES FOR LIQUID LIME-SULPHUR 5 



In view of these very conflicting data, further experiments were 

 deemed necessary, and the entomologists of the Insecticide and 

 Fungicide Board, working under the direction of the Bureau of 

 Entomology, have, therefore, very carefully tested a representative 

 series of the dry substitutes for liquid lime-sulphur, as dormant sprays 

 against the San Jose scale. ^ 



These preparations have been tried at several dilutions under 

 practical orchard conditions as dormant sprays against the San Jose 

 scale on peach trees in Mississippi and Alabama and on apple trees 

 in Indiana and Virginia. In every case unsprayed trees and trees 

 sprayed with liquid lime-sulphur were included as controls. 



The tests, which cover a period of three years and have been car- 

 ried on in four different States, form the basis of this report and they 

 are confirmed by numerous other experiments that have been 

 made in cooperation with the writers in other parts of the country.'' 



MATERIALS USED 



All of the materials used in these experiments were purchased in 

 the open market, analyzed, and kept under seal until tested. New 

 samples were collected each year and nothing but fresh material, 

 which had not been exposed to the air, was used. Although the 

 difl'erent samples vary slightly in chemical composition, they are, 

 on the whole, very similar and typical of the dry substitutes for 

 liquid lime-sulphur now being sold. The analyses of the preparations 

 tested are given in tables preceding each set of experiments. 



LIQUID LIME-SULPHUR 



A good commercial liquid lime-sulphur solution should test from 32 

 to 33° Baume (sp. gr. 1.283 to 1.295), and analyze approximately as 

 follows: Calcium polysulphide 30 to 32 per cent; calcium thiosulphate 

 1.5 to 2.5 per cent; traces of calcium sulphate; impurities from the 

 lime; and the remainder water. A comparison of the composition of 

 the liquid and dry lime-sulphurs shows that the latter contain roughly 

 about twice as much calcium polysulphides; from three to five times 

 as much calcium thiosulphate; and, in addition, from 8 to 14 per cent 

 of free sulphur, wliich does not occur in liquid lime-sulphur solution. 



Since a gallon of commercial liquid lime-sulphur (32° Baum6) 

 weighs about 10.7 pounds and contains approximately 32 per cent 

 of calcium polysulphides, a dilution of 6.66 gallons to 50 gallons of 

 spray (1 to 7.5), which was the strength used in the tests here reported, 

 will furnish approximately 22.8 pounds of calcium polysulphides in 

 €ach 50 gallons of spray material. 



RECORDS TAKEN 



Two kinds of records were taken in these experiments, one on the 

 hibomating scales and one on the young scales settling on new wood. 



In order to determine the effect of the treatment on the hibernating 

 scales, a number of twigs and branches were cut from ail parts of the 



' The field exjHjrlmcnts were under Ihc direct supervision of J. J. Culver, who also made nearly all of the 

 recf>rd3. 



' A. J. Ackerman In Arkansas, O. I. Snapp In MLsslsslppl, J.J. Culver In Georgia, and J.E. Fouserand 

 J J Davis In Indiana. 



