1o. 42, SECOND SERIES, FOURTH EDITION. 
SB ° 
= nited States Department of Agriculture, 
ENT BUREAU OF ENTOMOLOGY. 
L. O. HOWARD, Entomologist and Chief of Bureau. 
. 
HOW TO CONTROL THE SAN JOSE SCALE. 
By C. L. Maruatt, 
Entomologist and Acting Chief in absence of Chief. 
THE SAN JOSE SCALE A PERMANENT FACTOR IN FRUIT GROWING. 
The San Jose scale is so widely disseminated and has become so 
firmly established in the principal deciduous-fruit regions of this 
country that its extermination is now, in most cases, out of the 
question. In the main, therefore, the San Jose scale must be recog- 
nized as a permanent factor to be regularly dealt with as are other 
insect evils or the fungous diseases of plants. 
Extermination is possible only where the scale is detected at the 
very outset on new or recently planted nursery stock or at least 
before any considerable chance of spread has been afforded. It is true 
that by the greatest care in the introduction of nursery stock the San 
Jose scale may for years, perhaps, be kept out of districts now free 
from it, and one is warranted, therefore, in adopting every precaution 
to avoid introducing this scale and even to attempt extermination 
wherever the conditions are reasonably favorable. There is only one 
method of exterminating the scale, and that is by digging up and 
burning all infested trees. This is an heroic remedy and is advised 
only under the conditions of very recent introduction of nursery 
stock—in other words, where the scale is discovered within a few 
months after the purchase of the infested trees. If the scale has 
passed an entire breeding season in an orchard, it will have spread 
much more widely than any inspection will indicate and very likely 
will have gained a footing on wild and ornamental plants other than 
fruit trees, from which it will reintroduce itself into neighboring 
orchards or into new plantings, however thorough may have been the 
attempts to eradicate it. 
THE SAN JOSE SCALE CAN BE CONTROLLED. 
While, therefore, one is undoubtedly justified in asserting that the 
San Jose scale is to be a permanency, it by no means follows that the 
profitable growth of deciduous fruits is seriously menaced on this 
account. The experience in California, covering many years, has 
abundantly demonstrated that this scale insect can be controlled, and 
the more recent experience in the East points indubitably to the same 
conclusion. In other words, by proper repressive and remedial treat- 
