30 FUMIGATION OF APPLES FOR SAN JOSE SCALE. 
TasBLe XIII.—Corroborative results of effect of fumigation with hydrocyanic-acid gas on 
scales and fruit in different kinds of packages. (Package series 1907-8.) 
1 } | 
| | Rate at | | Num 
Experi-| which Length | ber of 
ment | Variety of apple. | Kind of package. | potassium | of ex- | scales | Effect on eee a 
No.— | cyanid was posure.| exam- | SC@-€S- Bone: 
| used. | : ined. | 
|e ‘Gr. percuft. Hours. | 
Seeeaes | Baldiwink ==2---- | Barrel, top open......--- 0. 30 1 | 3,400 | Alldead.. Noinjury. 
Se a eae donne [Sees Woe nt tee .30 Salts. 2316 | ous | aaa: 
COs IE ae do....--.--..| Barrel, with 20 inch . 30 225703 cdl e ss) SD 
auger holes in each end. | 
Disses | eps GOns eA as | Pee Ofc eee eee . 30 Bi Sh CCl. 2 2 Do. 
Oss | Roxbury Russet.| Box, fruit wrapped... -..| ~30 | I 25 (ls) Ie ClO 2 Do. 
| Bll DoW les -CO.- 5 Do. 
OSE Mera CO EN aes ess ere OKO ets Bebe so | 30 | 
| | | | 
One barrel of scale-infested Rhode Island Greening apples, from 
Niagara County, N. Y., but from another orchard than the first used | 
in 1906-7, was fumigated February 5 to determine if injury would 
result as in the earlier tests. An iron header replaced the usual barrel 
head, the open end turned down over the generator. Three examina- 
tions of this fruit were made, the counts including 2,860 scales, all 
of which were found to be dead. The fruit, however, was more or 
less injured and scalded as described for 1906-7. | 
SUMMARY OF RESULTS. 
Strength-of-gas series (Table IIT).—In the fumigation of fruit loose 
in baskets all scales were killed with strengths of potassium cyanid 
at rate of from 0.10 to 0.50 gram per cubic foot, and exposed forty- 
five minutes. Five hundredths of a gram of cyanid per cubic foot 
was not entirely effective. No injury resulted to the fruit treated, 
namely, the Baldwin. 
Length-of-exposure series (Table IV)—Baldwin apples loose im 
baskets were not injured by the use of potassium cyanid at the rate 
of 0.20 gram per cubic foot with periods of exposure ranging from 
twenty minutes to three hours. In every instance the scale insects 
were all killed. 
Package series, 1906-7 (Table V).—Fumigation of fruit in barrels 
opened in various ways to permit access of gas gave apparently 
variable results as to effect on the scales. All insects were not with 
certainty killed, except in the case of fruit in boxes, wrapped and un- 
wrapped, and in barrels in which each head had been perforated with 
numerous auger holes. Scales on apples in unopened barrels were 
not killed to any extent, as the packages were too tight to allow 
entrance of the gas. 
Package series, 1907-8 (Table X II).—In the package series of tests 
in 1907-8, with boxes, fruit wrapped and unwrapped, and with barrels 
opened in various ways, using potassium cyanid at the rate of 0.30 
