EXPERIMENTS IN 1907-8. 



27 



Rhode Island Greening apples were used, as shown in the following 

 table : 



Table X. — Effect of fumigation with carbon bisulphid on scales and fruit. 



E 'P« r '" : Varietvot 



| Fumigant 



Kind of package. and rate at 



j which used. 



Time 

 of ex- 

 posure. 



Num- 

 ber of 

 scales 

 exam- 

 ined. 



Effect on 

 scales. 



Effect on 

 fruit. 



21 Baldwin 



22 | do 



23 do 



24 do 



25 do 



^-bushel basket 



do 



do 



do 



do 



C. c. per cu.ft. 

 CS 2 0.069.... 



do 



CS 2 0.1384... 

 CS 2 0.2768... 

 CS 2 0.453.... 

 CSjl.81 



CS 2 0.453.... 

 CS 2 0.138.... 



Hours. 

 3 



3 

 3 

 3 

 3 



3 



3 

 3 



1,618 



1,405 



2,165 



2,040 



995 



770 



650 

 930 



Live scales No injury, 

 abundant. 



do Do. 



do Do. 



do 1 Do. 



do ! Do. 



45 ! Rhode Island 



Greening. 



46 do 



47... do 



Apples loose on floor 

 of box. 



do 



do 



do | Do. 



do i Do. 



do Do. 



1 









Examination of fruit as to condition of the scales in Nos. 21 to 25 

 was made November 27, about two weeks after treatment; and 

 Nos. 45 to 47, December 29, approximately an equal interval after 

 treatment; each lot was again examined about two weeks later. 

 In No. 25 the carbon bisulphid was used at the rate of 0.453 c. c. 

 per cubic foot. This is equivalent to 1 pound to 1,000 cubic feet. 

 Using this as a normal, doses were consecutively decreased by one- 

 half, Nos. 21 and 22 being duplicates. In the second series of tests, 

 in which the fruit was placed on the floor on the boxes, the carbon 

 bisulphid was used much stronger in the case of No. 45 — that is, 1.81 

 c. c. per cubic foot, approximately equal to 4 pounds per 1,000 

 cubic feet. As to the period of exposure, namely, three hours, it 

 was realized that this was perhaps too short, but in actual practice 

 it would be undesirable to greatly lengthen this on account of the 

 need of expedition in work of this character. It is not improbable 

 that where fruit could be subjected for several hours, as overnight, 

 to carbon-bisulphid fumes a heavy dose might be effective in 

 destroying the scales and without injury to the fruit. 



As shown, none of the strengths with the three-hour exposure 

 was at all effective in killing the scale. In the case of No. 45, where 

 the greatest strength was used, there were 120 live scales, of a total 

 of 770 examined, or a little more than 15 per cent of the insects 

 counted; or on the basis of live scales present, as shown by the 

 condition of the checks, approximately 28 per cent came through 

 alive. In no instance was there any injury to the fruit. 



EXPERIMENTS IN 1907-8. 



In the package series of tests made during the winter of 1906-7, 

 with the exception of the commercial boxes and barrels with both 

 heads perforated with auger holes, a few scales were found on fumi- 

 gated fruit which were so nearly normal in color and appearance 



