32 INSECTS OF ECONOMIC IMPORTANCE 



The first dusting- experiments in which dry sul- 

 ])hur was used to replace liquid lime-sulphur were 

 made by Blodo-ett in igii/*^ These experiments 

 were continued durin^^ 191 2 and 191 3. The results 

 were encoura.i^ing- and the work was continued dur- 

 ing: 1914 bv Reddick and Crosby/''^ The materials 

 recommended wxre finely o^round sulphur 90 pounds, 

 and powdered arsenate of lead 10 pounds, applying 

 from ij^ to 3 pounds of the mixture per tree at 

 each dusting-. Later recommendations advise 85 

 parts of sulphur to 15 parts of powdered arsenate 

 of lead.^*^ The results for the control of chewing 

 insects and apple scab were encouraging and fur- 

 ther experiments are now in progress. 



PUMPS 



Atomizers, hand sprinklers, buckets, knapsacks, 

 barrel, power sprayers. The essentials of a good 

 pump are brass or bronze working parts, ball valves, 

 and readily accessible parts. 



NOZZLES 



1. The first nozzles threw a nearly round solid 

 stream, like a garden hose. 



2. The second group of nozzles consisted of those 

 in which the stream having passed the orifice 

 proper is modified by some obstruction that breaks 

 it or scatters it. The "climax," ''Ball," and 

 ''Lewis" are examples. 



3. The third and most perfect type is known as 

 the rotary or eddy-chamber nozzle. This is repre- 

 sented, typically, by the Vermorel. Later modifica- 

 tions are the "Friend" and "Alistry." The Vermo- 

 rel is of American origin although bearing a French 



60 Blodgett— Cornell Univ. Expt. Stat, Bull. 340. 



67 Reddick and Crosby— Cornell Univ. Expt. Stat., Bull. 354- 



68 Reddick and Crosby — Cornell Univ. Extension, Bull. i. 



