308 ReporT OF THE DEPARTMENT OF ENTOMOLOGY OF THE 
sulphur wash. Their actual value for this purpose and the condi- 
tions under which they may be safely employed are problems 
for future experimentation. 
The fact that fumigation with hydrocyanic acid gas, in addition 
to proving safe to the plants, was the only one of the remedies 
employed that completely jdestroyed the scales, deserves special 
emphasis. This process is the most efficient means of disinfecting 
nursery stock and its utility for this purpose has been abundantly 
established by many experiments and by the experience of careful 
nurserymen. While it is not an absolute guarantee of the im- 
munity of the trees from destructive insects, it is without question 
the most effective method of accomplishing their destruction. Its 
efficiency and safeness are proportionate to the care that is exer- 
cised in carrying out the details of the operation. For dug dormant 
stock, infested with the San José scale, fumigation is the more 
reliable treatment. 
