26 FUMIGATION OF APPLES FOR SAN JOSE SCALE. 



, In examining the fruit, apples were selected from the top, middle, 

 and bottom of the barrel, as usual. It will be noted that all scales 

 were killed, except in case of Nos. 68 and 69. After fumigation of 

 Nos. 68 to 70 it was found that one of the quarter packages of cyanid 

 in which the total dose had been divided had failed to drop into the 

 acid jar beneath, so that the quantity of cyanid used was in reality 

 at rate of 0.225 gram per cubic foot, instead of 0.30 gram as indi- 

 cated in the table. In No. 68, four scales were found on fruit from 

 the center of the barrel which were considered doubtful. In No. 69, 

 one scale only was doubtful, and this also on an apple found in the 

 middle of the barrel. 



In summarizing the hydrocyanic-acid gas tests during the winter of 

 1906-7 it must be said that the results were far from satisfactory. 

 In all cases of fumigation where the apples were more or less loose, 

 as in baskets, the scales were invariably all killed, and in the tests 

 of the effect of the gas upon the various varieties of apples no injury 

 whatever resulted, even though excessive strengths were used — 

 much stronger than necessary to destroy the scales. The exception 

 of the Rhode Island Greening from western New York, however, is 

 to be noted, and as shown in Table VII no strength of gas was found 

 which did not injure the fruit. 



In the package series, including the treatment of fruit in boxes 

 and barrels as would be necessary in commercial use, there was lack 

 of uniformity in killing the scales. As already stated, this was 

 probably more apparent than real and resulted from error in classi- 

 fication of the insect as to whether dead or alive, as the fruit was 

 held under temperature conditions which would perhaps greatly 

 favor their preservation and natural color. However, in all cases 

 where the barrel heads were perforated with auger holes and in 

 boxes with fruit wrapped or unwrapped all scales were killed. 



TESTS OF CARBON BISULPHID. 



In the preliminary tests of f umigants, one of ' those tried was 

 carbon bisulphid. The first test was made November 14, placing 

 scale-infested Baldwin apples in one-third bushel baskets on the 

 platform in the fumigating boxes. The carbon bisulphid was 

 exposed in shallow dishes placed on top of the fruit. The period 

 of exposure was uniformly three hours, the doses, however, varying 

 as shown in the table. On account of the poor results secured 

 in this test, carbon bisulphid was again tried December 14 (Nos. 

 45 to 47, inclusive), the fruit being placed on the floor of the boxes 

 and the carbon bisulphid dishes above, so that if possible the fruit 

 would be more thoroughly subjected to the fumes, as the liquid 

 evaporated and the gas sank to the floor. In this latter, infested 



