248 TWENTY-FIFTH ANNIVERSARY REPORT. 
SAN JOSE SCALE. -_ 
(Aspidiotus perniciosus Comstock.) 
In 1894, the San José scale was discovered for the first time on 
Long Island’ and efforts were immediately directed to discover 
means of controlling this pest in several nurseries, in which it 
was found, and which, aside from a few private yards and or- 
chards, were the leading centres of infestation. At this time there 
was no question but that this species was already distributed in 
many parts of the State where its presence was unsuspected. As 
this pest, from its ravages in California, was known to constitute 
one of the most difficult problems with which fruit growers and 
nurserymen have to contend, the Station directed special efforts to 
ascertain other localities where it was present, attention being largely 
given to nurseriegy and to orchards of recent planting. It was 
hoped by this means to retard the spread of the species in the com- 
munities in which it was found and to prevent, as methods of con- 
trol were developed, its further dissemination through infested 
nursery stock. The studies that were undertaken on this subject 
may be grouped under the headings: (1) The San José scale in 
nurseries, and (2) the San José scale in orchards. 
San José scale im nurseries — As fumigation for the treatment 
of scale insect on citrus trees had proven the most efficient means 
of destroying the scale in California, experiments? were commenced 
by this Station in 1895 to determine the limits of effectiveness and 
safe use of hydrocyanic gas upon nursery trees. In the preliminary 
tests!” upon dormant nursery stock, fumigation, using the standard 
amount of potassium cyanide, proved entirely destructive to the 
scale and safe to the plants; and it was then concluded that this was 
the cheapest and most reliable treatment for nurserymen who 
handle and ship fruit trees in large quantities. 
Besides treating importations and spraying doubtful stock in the 
field, an additional safeguard in the nursery to prevent the 
dissemination of the scale on the premises is an_ efficient 
treatment of bud sticks, scions, etc., especially if such are taken 
from infested plantations. As fumigation was proving well 
adapted to dormant trees, it was desirable to also extend its use 
* Bul. 87 Rpt. 14:350 (1805); Insect Life, 7:284; N. Y. State Mus. Rpt. 
3: No. 13 (1895). 
°U. S. Dept. Agr. Rpt. 1887; Insect Life, 3:457 (1890). 
® Rpt. 14:6090-613 (1895): Bul. 136 and Rpt. 16:467, 468 (18907). 
_ 
