June, '09] JOURNAL OF ECONOMIC ENTOMOLOGY 215 



sion of the views of other workers as to the most important problems 

 existing in this particular field of investigation. 



The paper will therefore be confined to a general discussion of the 

 project, leaving out entirely the question of results which have already 

 been obtained. For a general understanding of the project, its sub- 

 ject and objects may be stated as outlined in the writer's plan of 

 work. 



Subject. — An investigation of the factors governing the production, 

 diffusion and insecticidal efficiency of hydrocyanic acid gas and car- 

 bon di-sulfid vapor as used in economic entomology. 



Object. — 1. To establish a scientific basis for practical working re- 

 quirements under known conditions. 2. Determination of minimum 

 effective time and dosage required by various insect species. 3. De- 

 termination of maximum safe time and dosage usable with various 

 plants. 4. Standardization of effective and economical formula? for 

 various needs. 5. Determining modifications required for effective 

 w^ork under varying conditions of temperature, moisture, light, insect 

 protection and plant resistance. 



Need for this Investigation. — From many points of view it would 

 seem that this is one of the most important general fields of investi- 

 gation demanding immediate attention by the economic entomologists. 

 The general requirement for the fumigation of nursery stock before 

 its sale and distribution has led to considerable experimental work in 

 the use of hydrocyanic acid gas. The results obtained are in many 

 instances indefinite, doubtful, or even contradictory, and as a rule the 

 experimental work has been done under such conditions that no 

 reasonable explanation of these inconsistencies can be given. The 

 commercial value of the stock thus treated must amount to many mil- 

 lions of dollars annually. The cost of treatment, while small as com- 

 pared with the value of the stock itself, is still a large item in the ag- 

 gregate. 



Besides its use for treatment of nursery stock while in a dormant 

 condition, hydrocyanic acid gas is coming to be extensively used for 

 the treatment of citrus trees and green house crops, involving its ap 

 plication to living plants which may be in an active growing condition. 

 The reasons for susceptibility of various plants to injurv^ by gas 

 treatment are but vaguely understood, while their importance as 

 bearing upon the general adoption of fumigation methods in green 

 house and orchard work is very great. 



The loss occasioned by insects to stored cereals and their products 

 was estimated by Mr. Marlatt for 1904 as being over 100 million dol- 

 lars. These losses are particularly severe with corn and various 



