22 



FUMIGATION OF APPLES FOR SAN JOSE SCALE. 



fully packed and the "iron header" put in place, the open end down. 

 The single examination, made December 29, of fruit from the three 

 parts of the barrel included 2,290 scales, of which 10 were doubtfully 

 dead. In Xos. 41 and 42, fumigated December 1, the usual com- 

 mercial apple box w^as used, in the former the fruit being unwrapped, 

 and in the latter wrapped with the paper usually employed for this 

 purpose. In both cases the fruit was examined twice (December 19 

 and 31) and all scales were found dead. With this variety, how- 

 ever, namely, Rhode Island Greening, from western New York, there 

 was marked injury to the fruit from the gas. This injury was evi- 

 denced by a browning or " scalding" of the skin, especially around 

 the calyx end of the fruit, including the calyx basin and adjacent 

 parts. Plate II, figure 2, shows the color and locality of typical gas 

 injury to this variety, which very closely resembles the ordinary cold- 

 storage " scald." 



VARIETY-OF-FRUIT SERIES. 



To test the susceptibility of various varieties of apples to gas injury 

 a miscellaneous collection was secured from the market in Washing- 

 ton. The origin of the fruit was not known, and it was free from the 

 San Jose scale. About one peck of apples of each sort was used, 

 placed in one-third bushel baskets, and to each basket were added 

 20 badly infested Baldwin apples, to determine the effect of treat- 

 ment on scales. Three of the baskets were placed in each fumi- 

 gating box, and the entire 15 thus exposed simultaneously. The 

 varieties used and other details are given in Table VI. 



Table VI. — Effect of hydrocyanic-acid gas on different varieties of apples. Exposure, 

 one hour; potassium cyanid used, 0.30 gram per cubic foot. ( Variety series.) 



Experi- 

 ment 

 No.— 



Variety of apple. 



Kind of 

 package. 



Rate at 



Num- 



,-hiehpotas- Lmgth berof 



Effect on 

 scales. 



ined. 



Effect on 

 fruit. 



Tolman sweet 



Yellow Bellflower 



Fallawater 



Winesap 



Fameuse 



York Imperial 



Ben Davis 



Lavaar 



Pound Sweet 



Rhode Island Greening. 



Northern Spy 



King 



Grimes Golden 



Baldwin 



Peck Pleasant 



^-bu. baskets 

 do.a 



do.« 



do.a 



do. a 



do.a 



do. a 



do.a 



do.a 



do.a 



do.a 



do.a 



do.a 



do.a 



do.a 



Gr. per cu.ft. 

 0.30 

 0.30 

 0.30 

 0.30 

 0.30 

 0.30 

 0.30 

 0.30 

 0.30 

 0.30 

 0.30 

 0.30 

 0.30 

 0.30 

 0.30 



Hours. 



1 

 1 

 1 

 1 

 1 

 1 

 1 

 1 

 1 

 1 



1 

 1 

 1 



1,037 

 1,057 

 1,109 

 1,010 

 950 



All dead 

 ..do... 

 ..do... 

 ..do... 

 ..do... 

 891 ...do... 

 986 ...do... 

 750 ...do... 

 .do... 

 .do... 

 .do... 



1,210 

 940 



1,195 

 967 

 910 



1,140 



..do. 

 ..do. 

 ..do. 



750 ...do. 



No injury. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 



a In each basket were also placed 20 scale-infested Baldwins to determine effect on scales. Apples from 

 Center Market, Washington, D. ('. 



Fumigation was done November 30, 1906, and the fruit was kept 

 under observation for several weeks. No gas injury whatever 

 developed and, as will be noted, all the scales on the infested Bald- 

 wins were killed. The absence of injury to the Rhode Island Green- 



