4 BULLETIN 833, U. S. DEPARTMENT OF AGRICULTURE. 



Lakes and the northern and central Atlantic seaboard. On the Pa- 

 cific coast it is reported from California and Oregon, and its presence 

 has been confirmed in South Dakota, Tennessee, and Georgia. 

 Doubtless a careful survey would locate many additional isolated 

 infestations which have not been brought to the attention of State or 

 Federal entomologists. 



VARIETIES AFFECTED. 



While the chrysanthemum midge has been recorded from central 

 and southern Europe as seriously injuring the common white or ox- 

 eye daisy (Chrysanthemum leucanthemum), as well as C. corymbosum, 

 C. atratum, C. ja/ponicum, and C. myconis (11), its depredations in 

 North America are confined to practically all of the commercial 

 chrysanthemums, both the single and pompon varieties. The first 

 infestation in this country was reported on the variety Mistletoe, 

 and according to Felt (14, 15, 16) this variety appears to be very 

 susceptible to the attacks of the midge. 



Although several attempts have been made to infest the Shasta 

 daisy and the common field daisy, 0. leucanthemum, it has not been 

 possible to get the ovipositing female to lay eggs on them. This is 

 of much importance, for should the infestation spread to this common 

 weed, there would be great difficulty in eradicating this pest. 



A. Gibson lists the following varieties as being fairly free from injury : 

 Bob Pulling, Gertrude Peers, Daily Mail, Oconta, Mrs. G. C. Kelly, 

 W. Wood Mason, F. T. Quilleton, and E. T. Quittington. All the 

 above varieties are the blended product of C. indicum and O. mori- 

 folium, both of which grow wild in China and Japan. He reports 

 the following varieties as being practically ruined: Smith's Advance, 

 Ivory, Bonnaffon, Wm. Turner, Western King, and Englehart. 



Observations made by H. F. Dietz in the Middle West showed 

 that the Wm. Turner variety had lost all the crown buds. In case 

 of a thick infestation on the variety Dr. Enguehard all of the plants 

 had to be discarded early in the season; also all Chadwick varieties, 

 as well as Elberon, Major Bonnaffon, and Golden Mensa. The varie- 

 ties which seemed to be least injured were Golden Age, Harvard, and 

 White Bonnaffon. 



In some of the greenhouses of the District of Columbia during the 

 season of 1918-1919 such varieties as Mensa, William Turner, and 

 the white and yellow Bonnaffon were completely ruined on account 

 of the severe infestation. 



ECONOMIC IMPORTANCE. 



Although a comparatively recent introduction this insect now 

 seems to be firmly established in the United States and is one of the 

 most important pests to be reckoned with by chrysanthemum 

 growers. 



