3828 REPORT OF THE DBPARTMENT OF ENTOMOLOGY OF THE 
oil did not injure the foliage except when used pure and then 
only slightly. So far as could be ascertained, temperature and 
weather conditions had little effect on the results, as the effects 
of spraying were practically the same under varying conditions of 
heat and cold, sunshine and cloudy skies. 
The results of these experiments are also sufficiently definite 
to indicate that kerosene oil may be used during the winter oR 
apple and pear trees at a percentage (40 per ct.) strong enough to 
kill the scale without endangering the tree; but that it is imprac- 
ticable for use on peach trees and dangerous to plum trees. 
II. METHODS OF COMBATING THE SAN JOSE SCALE. 
There are two principal methods of combating the San José 
scale in the orchard: First, fumigating the infested .trees with 
hydrocyanic acid gas; and second, spraying with some caustic 
substance that will penetrate the scale and kill the insect beneath 
or seal it over so firmly as to entirely smother it. 
FUMIGATION. 
‘Fumigation is practicable only for comparatively small trees 
that can be safely cut back to about twelve feet in height and 
about eight feet in diameter. -Either a tent or a canvas box may — 
be used. The former is likely to be unsatisfactory because of the 
difficulty in accurately estimating its cubic contents and the 
trouble involved in handling. The box fumigator’ avoids these 
difficulties and if not too large is more satisfactory. A modifica- 
tion of the box type has been used by Prof. W. G. Johnson? with 
reported success. It consists of a box which is let down over the 
top of the tree by means of a mast and pulley. The top of the | 
box consists of a canvas hood which adjusts itself to the height 
of the tree. The cubic contents of the rigid part of the box can 
be easily ascertained and the cubic contents of the extended 
hood estimated. 

1A form of box fumigator is described in Bulletin 181 of this Station. 
?V. S. Dept. Agr. Div. Ent., Bul. 20, n. ser., pp. 48-45. 
