204 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 15 



very high temperature, fumigating on an especially cold night and allow- 

 ing the plants to become chilled, when the ventilators are open to 

 permit exit of gas. Moisture in the house will not materially affect 

 the result except that if the walks and soil are very wet, they will 

 absorb so much of the gas that the fumigant will not be effective against 

 the insect. 



Mr. R. L. Webster : In some of the work that I did in New York State, 

 it seems that moisture — particularly inside the plant — not moisture on 

 the outside or the moisture of the air — was conducive to injury. It 

 seems that the gas enters a plant in the same way that carbon dioxide 

 does; through the stomates. It gets into the intercellular spaces, and 

 then if there is a good deal of moisture it penetrates readily into the 

 cells, causing injury. A good deal of this is theoretical but it seems 

 to work out pretty well. It is largely a question of moisture in the 

 cell walls of the plants. 



President George A. Dean: The next paper is by C. A. Weigel 

 and Charles F. Doucette. 



FURTHER OBSERVATIONS ON THE STRAWBERRY ROOT 

 WORMi ON ROSES 



By C. A. Weigel and C. F. Doucette 



In a preliminary report- given in an earlier number of this Journal 

 the seriousness of this insect as a menace to greenhouse roses was dis- 

 cussed. Since then a careful survey has given evidence that this insect 

 is now of prime importance to rose growers in practically all of the com- 

 mercial rose districts of the United States, and in several establishments 

 the plants have been almost totally ruined for commercial purposes. 

 An active investigation of the life history and control measures was 

 inaugurated by the Bureau of Entomology in 1919, and since February 

 1920 conducted as a joint project in cooperation with Prof. J. G. San- 

 ders, Director Bureau of Plant Industry, Pennsylvania, with labor- 

 atory headquarters at Doylestown, Pa. The preliminary life history 

 studies which were started by Messrs. Weigel and Chambers were 

 subsequently taken up by the writers, assisted at intervals by Messrs. 

 Primm and Buckman of the Pennsylvania Bureau of Plant Industry. 



Life History and Habits 



The Egg : In the life history studies it was found that the eggs were 

 deposited in the curled-up, dead and dried leaves, singly or in masses 



^Paria canella Fab. 



=Jour. Econ. Ent. v. IS.'^pp. 226-232. 



