346 Report OF THE DEPARTMENT OF ENTOMOLOGY OF THE 
for the San José scale, and its valuable fungicidal qualities for 
various fruit diseases. The advantages claimed for this treat- 
ment by immersion, although they have not been well substantiated, 
are its convenience and general adaptibility for the purposes for 
which fumigation with hydrocyanic acid gas would be employed. 
This method of treating nursery stock has not been officially recog- 
nized, except by the Oregon State Board of Horticulture,) which, 
at the request of the nurserymen of that state, annulled on October 
8, 1906, Rule 8 of the quarantine regulations, requiring nursery 
stock to be fumigated, and substituted in its place a provision which 
compelled dipping in a standard solution of the lime-sulphur wash. 
Present interest in the probable utility of this treatment in actual 
practice is largely the result of the adoption of this rule. 
PRESENT STATUS OF DIPPING AS A MEANS OF DISINFECTING NURSERY 
STOCK. 
Dipping of nursery stock in various contact sprays is not a new 
practice and has long been employed for various purposes by nur- 
serymen, especially for the treatment of scions and budding sticks. 
With the appearance of the San José scale as a nursery pest, the 
immersion of infested trees in strong liquid insecticides was 
naturally, in view of existing practices, one of the first methods to 
be suggested and to be officially tested, to determine the value of the 
more promising sprays then in use, as disinfectants for this pest. 
Upon the discovery of the San José scale in nurseries on Long 
Island in 1894, Mr. F. A. Sirrine* of this Station directed some 
extensive experiments on the treatment of nursery stock, by im- 
mersion of trees in strong preparations of whale-oil soap, which 
was then regarded as the most efficient spraying insecticide for this 
insect. The results were not entirely successful and the failures 
were attributed to careless work in the dipping operations. Dip- 
ping of purchases of trees, before planting, in soap mixtures is still 
practiced by some fruit growers as a means of precaution, to pre- 
vent the introduction on their premises of destructive insects such 
as scales and root-inhabiting lice. 
In recent years, with the growing interest in this treatment, a 
number of experiments have been undertaken to determine the 
*Oreg. Bd. Hort., Bien. Rpt. 9: 120. 1905-6. 
* Ann. Rept. of this Station, 14: 612. 1895. 
