17 
Similarly, the whale-oil soap does not kill the eggs directly, though it 
may harden the egg-mass so as to prevent the hatching of a large pro- 
portion of young larva3. 
Resin Soaps. — Mr.Koebele experimenting through August, September, 
and October, found similarly good results from the kerosene emulsion, 
but that the crude petroleum, although much cfieaper, was more apt to 
injure the tree. His attention was, however, directed mainly to the 
preparation of resinous soaps and compounds on account of their greater 
cheapness. He succeeded in making a number of these mixtures which, 
when properly diluted, need not cost more than one-half to one cent 
per gallon and which produced very satisfactory results, killing the 
insects or either penetrating or hardening the egg masses so as to pre- 
vent the hatching of the young. One of the most satisfactory methods 
of making a resin soap is to dissolve one pound caustic soda in 1J gal- 
ions water to produce the lye ; then dissolve 2 pounds resin and one 
pound tallow by moderate heat, stirring in gradually during the cook- 
ing one quart of the lye, and then adding water until you have about 
22 pints of a brown and thick soap. This will make 44 gallons of wash, 
costing less than one-half cent per gallon. 
There is some slight difference between the experience of Mr.Koebele 
and Mr. Coquillett as to the value of soap washes, and the greater suc- 
cess which the former had with them as compared with the latter was 
probably due to the fact that his experiments were made during the 
dry or rainless season. The great point of interest, however, in these 
experiments is that they confirm in a remarkable manner the experience 
had in Florida. And I think you will agree with me that they justify 
the opinions which I have expressed in official writings. Such observa- 
tions as I have been personally able to make during my brief sojourn 
among you have greatly served to confirm me in those opinions, and 
while the resin soaps experimented with by Mr.Koebele are a valuable 
addition to our insecticides for the scale-insects, I find the experience 
in Florida repeated here, and all the more satisfactory washes have 
kerosene as their effective basis. There has been, however, a very 
great waste in applying it, and it is in this direction that reform is 
most needed. 
The fact cannot be too strongly urged that in the case of this Icerya, 
as of most other orange-feeding scale-insects, it is practically impossible, 
with the most careful and thorough spraying, to reach every one of the 
myriads on the tree. Some few, protected by leaf-curl, bark-scale, or 
other shelter, will escape, and with their fecund progeny soon spread 
over the tree again if left unmolested. Hence, two or three sprayings, 
not too far apart, are far preferable to a single treatment, however 
thorough. And this is particularly true of the pest we are considering, 
which lives on so many other plants, and which in badly infested groves 
is frequently found crawling over the ground between the trees. 
404— Bull. 15 2 
