BULLETIN 



OF THE 



Ohio Agricultural Experiment Station 



NUMBER 197. OCTOBER, 1908. 



THE CATALPA MIDGE. 



Cecidomyia catalpae Comstock. 



BY H. A. GOSSARD. 

 CHARACTER OF DAMAGE AND IMPORTANCE. 



Three distinct forms of injury are chargeable to the larvae of the catalpa midge. 



1. To the leaves, causing a form of leaf spot. 



2. To the terminal buds and ends of the branches. 



3. To the seeds in the pods. 



1. The adult midges must appear in late May and early June in 

 dinary seasons. About June 22, 1908, my assistants found injury 

 pronounced on many trees and numerous larvae were in the 

 terminal buds. A close examination of the material brought in from 

 the field soon discovered larvae on the leaves as well as in the buds, 

 and a few hours observation of hundreds of larvae on collected 

 leaves, as well as on leaves still on the trees, established their con- 

 nection with the leaf-spot trouble. In the center of many of the 

 spots could be found a larva with its head end inserted into a small 

 hole in the center of the spot from which it imbibed its nourish- 

 ment. Apparently the damage was caused by the removal of the 

 plant juices from the spot, as there seemed to be no separation of 

 the upper and lower epidermal surfaces over the injured area, nor 

 did the larva seem to bury the front part of its body between the 

 surfaces after the manner of some leaf-miners. Some spots just 

 commencing- to form could be found with young larvae feeding in 

 their centers. Hundreds of these spots could often be found on 

 single leaves, and large fruiting trees are sometimes so badly 



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