THE ROSE APHIS. 15 
TREATMENT IN THE GREENHOUSE. 
For the treatment of the rose aphis as it occurs in greenhouses the 
nicotine solutions may be used, but at a lower strength than advised 
in the preceding paragraphs. Conditions vary somewhat, but it is 
believed that in most cases if the nicotine solution is used at the 
strength of 1 part to 2,000 of water it will not injure the rose plants 
if applied on a dark day or late in the afternoon so that the plants 
will not be exposed to reflected sunlight through the glass. 
When greenhouses containing different forms of plants are syringed 
with a forcible stream of water or with neutral soaps of the castile 
or similar types for the red spider and other insects, the rose aphis 
and other green aphides will also be killed. The same is true in 
regard to fumigations with hydrocyanic-acid gas for other rose pests. 
Directions for the use of hydrocyanic-acid gas for the fumigation of 
greenhouses and cold frames are given in Circular No. 37 of the 
Bureau of Entomology. In the experience of Dr. A. F. Woods, the 
author of that publication, the young growth of roses is particularly 
sensitive and has been more or less injured in experiments in the use 
of this gas. This is particularly true of such varieties as "Perle des 
jardins," "Mermet," and "Bride." 
ADDITIONAL COPIES 
OF THIS PUBLICATION MAY BE PROCURED FROM 
THE SUPERINTENDENT OF DOCUMENTS 
GOVERNMENT PRINTING OFFICE 
WASHINGTON, D. C 
AT 
5 CENTS PER COPY 
