14 
the larger quantity about 100 gallons and the smaller about 20 — 
of spraying mixture. 
When hard water is employed in the making of the emulsion or in 
diluting afterwards, it is necessary to use about 25 per cent more soap, 
or preferably the water may be broken with lye, or rain water may be 
used. 
In the use of kerosene or other oily washes on plants, the applica- 
tion should be merely sufficient to wet the plant without causing the 
liquid to run down the trunk and collect about the crown; usually at 
this situation there is a cavity caused by the swaying of the plant in | 
the wind, and the accumulation of the insecticide at this point may 
result in the death or injury of the plant. It is even advisable to 
mound up the trees before spraying or to see that the earth is firmly 
packed about the base. Care should also be taken in refilling the tank 
to see that no free oil is allowed to accumulate in the residue left at 
the bottom. 
In line with the use of kerosene emulsion may be suggested the use 
of pure kerosene mechanically combined with water in the act of spray- 
ing, as is now effected by a style of pump specially made for the pur- 
pose. <A 20 to 25 per cent solution of the kerosene can be used without 
danger to the plant in its dormant condition, but it is necessary to 
watch the apparatus employed for this work very carefully to see that 
the proportion of oil to the water does not change, and on the whole 
it is much safer and more satisfactory to use the kerosene emulsion, 
the strength of which may be known definitely in advance and is not 
subject to variation. 
SPRING OR PALL TREATMENT WITH ARSENICALS. 
The possibility of destroying the larve of the peach twig-borer by 
spraying the plants with arsenicals, either in the fall or spring, has also 
been suggested, but such treatment demands the greatest caution on 
account of the extreme sensitiveness of the foliage of the trees ordi- 
narily attacked by this insect to scalding when sprayed with these - 
poisons. 
The fall treatment is directed against the last brood of lar vie, and to 
be effective the poison should reach the parts of the plant where the 
egos are most apt to be placed, presumably the crotches of the branches. 
Many of the larve might thus be poisoned while eating through the 
bark preliminary to the construction of their winter retreats. To 
effect anything of value by this course the poison must be applied 
early—that is, before the eggs are deposited—and the feasibility of the 
treatment will depend somewhat on the condition of the trees and the 
damage that might result from scalding of the foliage in late summer. 
As aspring treatment, the arsenical spray should be applied to the 
trees at the moment the leaf-buds begin unfolding, so that the first meal 
taken by the over-wintered larv will be a poisonous one. The difficulty 
