UNITED STATES DEPARTMENT OF AGRICULTURE 
Contribution from the Bureau of Entomology 
L. O. HOWARD, Chief 
Washington, D. C. PROFESSIONAL PAPER May 3. 1919 
THE ROSE MIDGE. 
By E. R. SAsscer, Collaborator, and A. D. BorpEn, Scientific Assistant, Tropical 
and Subtropical Fruit Insect Investigations. 
CONTENTS. 
Page. Page 
PME O CU CGT ON aoe ee ee ee AP Hood aplante=n2 222 ek Swi Se ees 
History and distribution___________~_ 2 | Experiments in control______________ 4 
IDES CEG ON ga Bes es eee Zep VIGEhOOSMOLECOntLO Stes = a= eee a 
ihe wehi SOL ys eee peeclecr 4; Precautionary measures_____________ 8 
Seasonal history___________ et es Ame ater asuice lite Cte = en ne ae ee 8 
INTRODUCTION. 
The rose midge, Dasyneura rhodophaga (Coq.), an insect related to 
_the Hessian fly, is often the cause of considerable injury to roses 
grown under glass. In 1912 Davis (3)1 estimated that the loss due to 
this pest in two Chicago greenhouses would approximate $10,000 
annually. Subsequently this insect was reported by various ento- 
mologists as being especially injurious to the flower and leaf buds 
of the rose, distorting their growth and eventually causing them to 
turn brown and die. 
In the fall of 1916 an infestation was located at Colgate, Md., 
which, according to the owner, caused an annual loss of from $4,000 
to $6,000. Although the house was generally infested, the infesta- 
tion was limited to the following varieties of roses: Radiance (pink), 
Hadley (red), Russell (pink), and Killarney (white). The Hadley 
and Radiance varieties were most severely infested, scarcely a leaf 
or flower bud escaping attack. 
This infestation offered an excellent opportunity for determining 
a satisfactory means of controlling this pest in a commercial green- 
house, and, in collaboration with Prof. E. N. Cory, entomologist of 
the Maryland Agricultural Experiment Station, the investigation 
was begun in October, 1916. Results of these experiments are given 
on pages 6 and 7. 
1 Figures in parentheses refer to ‘‘ Literature cited,” p. 8. 
103858°—19 
