MASSACHUSETTS APPLE INDUSTRY. 39 



if thoroughli/ applied, may be used at a 1:10 dilution and still maintain its 

 high efficiency against scale. 



2. At the strengths recommended by their manufacturers, none of the 

 dry products has given as satisfactory control of scale as has the concen- 

 trated lime-sulfur solution, even when applied weaker than the usual 

 dilution. 



3. Tlie dry materials have shown, in actual field tests, a higher degree 

 of eifectiveness as compared with the lime-sulfur solution, than a com- 

 parison of their chemical content of polysulfide sulfur would lead us to 

 expect. 



1. The dry lime-sulfur and the sodium sulfur compound were about 

 equally effective, and greatly superior to the barium sulfur compound. 



•5. Great concentration of the dry materials is impractical from the 

 standpoint not only of cost, but also of application, owing to the large 

 amount of insoluble matter accumulating in the tank. 



It should be clearly understood that the above statements refer to the 

 concentrated lime-sulfur solution and the dry sulfides purely from the 

 standpoint of their efficiency as dormant sprays for the control of San 

 Jose scale, and have no bearing on any fungicidal value which the ma- 

 terials may possess. 



SOME RESULTS FROM SPRAYING AVITH SCALECTDE 



BY A. I. BOURNE 



For many years the question of oils for spray purposes has held the 

 attention of fruit growers everywhere. Because of their effectiveness 

 against San Jose scale, oil sprays have been used quite extensively, in 

 spite of tlie fact that, when not properly prepared, severe injury often 

 followed their use. This condition, at first inimical to the use of these 

 sprays, made comi^rehensive research studies necessary. These have been 

 organized under the sponsorship of the Crop Protection Institute. 



The main lines of endeavor in the investigation as conducted in Massa- 

 chusetts have fallen into two general classes. 



1. A study of both immediate and cumulative effects of Scalecide upon 

 \arious types of fruit trees common to Massachusetts orchards. 



2. A study of the effect of Scalecide upon various in.sect and other 

 j>ests, primarily those of orchard trees, and necessarily limited to the 

 sjiecies common to thi.s region. 



The study of the dift'erent phases of plant stimulation or other cumula- 

 tive effects following the continued use of Scalecide has not yet reached 

 the point where definite conclusions can be drawn. Certain results, how- 

 ever, along the line of the insecticidal value of this material, which our 

 tests have brought out to date, can be briefly reported. 

 ' Ajiplied as dormant sprays in the spring against the winter eggs of the 

 lOuropean red mite, with results drawn from counts of 20,000 to 25,000 

 mites of diff'erent stages, Scalecide and other materials showed the follow- 

 ing relative control values, as compared with unsprayed checks: 



Dormoil (a western type oil) 99 per cent 



Scalecide 98-99 jjer cent 



Sunoco 97 per cent 



Rex oil emulsion 89 per cent 



Lubricating oil emulsion 2% 90 per cent 



