INSECTS AFFECTING OHIO SHADE TREES 193 



, The work of this insect upon the catalpa was first 

 Bud Gnat mentioned in Bui. 7, Ohio Department of Agricul- 

 ture, Division of Nursery and Orchard Inspection. 

 During- the early summer, the tender growing- tips of the catalpa be- 

 come swollen and in time blacken at the point of injury. During 

 the early part of the season the injury is usually found 3 or 4 inches 

 below the tip, an*d at a lesser distance during late summer when the 

 tree is growing less rapidly. The tip above the injury dies. Fol- 

 lowing the death of the tip in early summer, the next node below 

 develops one or more branches and frequently a cluster of leaves, 

 giving the tree a bushy growth. Plate 24. The ultimate result 

 after continued topping is a stunted, crooked, forked, growth Plate 

 13. Fig. 2. 



An examination made last spring of all the twigs upon 15 three- 

 year-old catalpa trees revealed the fact that 49 percent of the tips 

 of the twigs had been injured by the bud gnat. 



If one of the injured twigs is examined by being cut open, small, 

 footless, yellow or white larvae will be found. If one of these is 

 placed on a smooth surface, it has the power to jump several inches 

 in the air. This is accomplished by raising both ends of the body 

 so that they almost meet above, and then with a sudden motion 

 straightening out. 



The insect has been under observation on the Experiment 

 Station farm since the summer of 1904. From observations made 

 in the field there appear to be two broods per annum, one in 

 early and another in late summer. The pupal stage is probably 

 passed under the surface of the soil, as the author was unable to 

 secure adults by placing twigs infested with the larva in cages that 

 did not contain moist soil. 



With so little understood concerning the pest it is difficult to 

 plan remedial measures. It has been suggested in Bui. 7, Ohio State 

 Department of Agriculture, Division of Nursery and Orchard In- 

 spection, that cutting the infested twigs and destroying them would 

 be of value during the summer. 



The Station plantings at Wooster indicate that the pest is less 

 serious in cultivated groves than in sodded ones. However, this ob- 

 servation can only be considered as an indication, as the cultivated 

 groves are younger than the sodded ones and the insect has thus 

 been unable to become so well established. 



