20 
BULLETIN 1439, U. S. DEPARTMENT OF AGRICULTURE 
adheres more closely to the surface of the foliage than does the fish 
oil, but the difference is slight. Corn oil is not so good an adhesive 
as either of the other two, but is much more efficient than any of the 
remaining adhesives tried, which rank in the following order: Pro- 
prietary miscible oil, proprietary casein product, lead oleate, flour, 
and soap. 
In view of the fact that fish oil is only slightly less efficient than 
linseed oil and is much less expensive, it is obvious that the former is 
the one to be recommended. In April, 1923, as previously remarked, 
the price of linseed oil was $1.17 per gallon, and that of fish oil 79 cents 
per gallon, in barrel 
lots; in March, 1925, 
the price of linseed 
oil was $1.23, and that 
of fish oil 75 cents per 
gallon; in May, 1926, 
the prices,in barrel lots, 
of linseed oil and fish oil 
were, respectively, 87 J^ 
cents and 70 cents per 
gallon. It is obvious 
how variable from year 
to year are the prices 
of such commodities. 
It can be readily seen 
that by the use of fish 
oil a great saving in the 
cost of spraying can be 
effected, especially 
when large quantities 
are used. 
Fish oil as an adhesive 
was used in arsenate-of- 
lead mixtures only. It 
was not used in combi- 
nation with Bordeaux 
mixture (7), nicotine 
sulphate, soap, or any 
other ingredients. 
Further experiments should be conducted to determine the value of 
this oil when added to other spray mixtures. 
In using fish oil as an adhesive one must bear in mind that the best 
results are obtained by adding the oil after the arsenate of lead has 
been well mixed with the water and while the mixture is being agi- 
tated. The mixture should be agitated at all times while it is being 
applied, not only to obtain an even coating of poison but to get maxi- 
mum adhesiveness. In high-power spraying the agitation of th< 
material is usually excellent, but in using the smaller outfits, such as 
the barrel pump, the agitation is sometimes poor, and satisfactory 
results can not be obtained either in the even distribution of the 
poison or in the adhesive qualities of the mixture. 
The best grade of fish oil should always be used. This is known as 
" light pressed" and is yellow to brown in color. A cheaper grade 
Fig. 16.— Undergrowth at Saugus, Mass., November 3, 1924, 144 
days after it was sprayed with arsenate of-lead mixture contain- 
ing corn oil as adhesive. The poison adhering is clearly shown. 
Livestock should not be allowed to eat vegetation so treated 
