28 FUMIGATION OF APPLES FOR SAN JOSE SCALE. 
as to give rise to doubt as to their condition, and these were there- 
fore uniformly regarded as alive. The preceding season’s work 
indicated that great range in strengths of gas was possible without 
injury to the fruit, excepting in the case of one variety, and in the 
case of loose fruit at least was entirely reliable in killing the scales. 
The variability in results of treatment of fruit in barrels required 
further tests, as if put to practical test 1t would be highly desirable 
that fumigation could be done without disturbing the fruit as 
originally packed. The tests in 1907-8 were therefore directed 
toward establishing a treatment for fruit im original packages, 
varying the strength of gas and the period of exposure. As in the 
preceding season, 0.30 gram of chemically pure potassium cyanid 
was adopted as a normal, and, while perhaps stronger than actually 
required, it was deaaple to lars an excess of strength, especially — 
since considerable latitude was allowable without danger of injury 
to the fruit. This dosage is furthermore approximately that already 
employed in treatment of dormant, deciduous-fruit nursery stock— 
that is, 1 ounce to each 100 cubic feet of space in the fumigatorium, 
The Baldwin variety was used, obtained, as previously, from Niagara 
County, N. Y., but from another orchard than the fruit used in 1906-7. 
The fruit was fumigated from November 29 to December 2, and at 
once placed in the outbuilding on the Agricultural Department 
grounds previously mentioned, in which the temperature ranged 
mostly from 30° to 40° F. 
Extended examinations of scales on apples before fumigation 
showed that 81.1 per cent of these were alive, ranging in age from 
quite young to mature gravid females, occurring mostly in the stem 
_and calyx cavities. The condition of the scales on fruit at this time 
and at different dates subsequently is shown in Table XI, sae for 
comparison as to condition of scales in fumigated fruit. 
TaBLE XI.—Condition of San Jose scale on unfumigated Baldwin apples during the 
winter of 1907-8 for comparison with condition of scale on fumigated fruit. 
l 
i ae _ Total 
| Number | Number | ) amber | Per cent 
Date examined. | of scales | of scales ‘ 
: scalesex-| alive. 
alive. dead. amined. 
Noveniber 29/1907. 0-. 2502 Seeeiso oe oy. Seen ee eee | 524 122 | 646) 81.10 
DecemibertlG sl 907.4 2422 Shean ee ee eee eee Seepeae nce 7 217 1,013 | 78.5 
December 21,1900 2. eee Sa eee eee eee Eos 344 109 | 453 | 78. 00 
January:35 1908. c-s0 25 nc oc as So a eee eI eee eee aeons | 930 499 1, 429 | 65. 08 
Hebruany:3, (1908... s- = ee ee en eee eee 302 454 756 39. 94 
March's 1908-556 ses su & Cos ok Lele Be pe ake aE | 101 | 954 | - 1,055 | 9.57 
PACKAGE SERIES, 1907-8. 
The fruit had been held in cold storage for a few weeks and at the 
time of fumigation the apples from the middle of the barrels were 
somewhat moist, not having yet dried from the condensation of 
