148 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 
THE EUROPEAN FRUIT LECANIUM. 
(Lecanium corni Bouché.) 
APPEARANCE OF THE INSECT. 
The insect heretofore generally known as the brown apricot scale 
belongs to the subfamily of scale insects, the Lecaniine, being naked 
but with hardened derm, and differs from the San Jose scale and 
European pear scale in that the horny covering of the full grown scale 
is a part of the body of the insect, while in the case of the other species 
mentioned the body is protected by a waxy covering made up from 
secretions and the molted skins of the larve. 
The adult female of the European fruit Lecanium is about one- 
eighth to three-sixteenths of an inch long, three-thirty-seconds to 
one-eighth of an inch wide, and about one-eighth of an inch high, 
yellowish in color, marked with black. The older scales are shiny, 
oval, convex, and often covered with a mealy pruinose deposit (see 
Pl. XT, figs). 
PLAN OF WORK AND METHOD OF ASCERTAINING RESULTS. 
In the winter of 1909 an infested orchard near San Jose, Cal., was 
selected and divided into 9 different plats of 14 trees each. Eight 
plats were used for trying out various sprays, and the ninth plat was 
left unsprayed for a check. 
It was planned to examine a number of twigs at intervals of two 
days, two weeks, five weeks, three months, and ten months from 
date of spraying for proportion of live and dead scales; also, to take 
into account the action of the different washes on the trees and to 
examine the fruit as to freedom from the sooty fungus. The effect 
of the sprays upon the growth of lichens on the trunk and limbs 
was also to be noted. Such a number of examinations was considered 
necessary as some of the sprays were immediate in their action while 
others acted over a longer period. 
APPLICATION OF SPRAYS. 
All of the plats were treated February 18 with the sprays indi- 
cated below, using a single bent-disk nozzle (with one-eighth inch-hole 
in disk) on each rod, the pressure being maintained at about 200 
pounds by means of a gasoline-power outfit. At this pressure the 
lichens were thoroughly soaked. From 4 to 5 gallons of liquid were 
used per tree and the work was very thoroughly done. 
SPRAYS USED AND METHOD OF PREPARATION. 
Plat 1, 6 per cent distillate-oil emulsion.—This was made after the 
formula given in Bulletin 80, Part IV, Bureau of Entomology. A 
concentrated emulsion was made by dissolving 30 pounds of fish- 
