February, '21] gossard and parks: hessian fly prevention 



57 



to make our breeding stations perform a statewide service and added 

 some new types of cage or trap to either breed out flies or else to catch 

 them in natural flight in the field. The three most practical were 

 named and defined as follows: 



1. Concentration cage. This was a tight store box without bottom 

 and with circular holes cut in the top for lantern globes fitted into them, 

 the globes being covered over the top with cheese-cloth tied in place. 

 Into this cage was put about two bushels of stubble and surface earth 

 known to contain healthy "flaxseeds" in great numbers. If the stubble 

 and earth heap was not moist, this was or should have been wetted with 

 one or two pailsful of water, because this loose heap dries out more 

 rapidly than field soil, and normal conditions are more nearly preserved 

 by adding the water. Water was also added as each rain occurred. 



2. Migration wire. Five linear feet of ordinary wire fly-screen, 

 two or three feet high, was set up on a frame with the lowest edge 

 elevated about eight inches to one foot above the ground and standing 

 north and south. A similar trap was set at right angles to it, east and 

 west. By this arrangement the chance for catching flies was equally 

 good no matter from which direction the wind blew. The wire was 

 coated with tanglefoot, the flies removed with a brush after each day's 

 count, and the tanglefoot renewed or freshened by brushing over it. 



3. Egg Record. Besides the traps just described, a strip of wheat was 

 seeded at each station in time to be of inviting size at the date when the 

 flies were expected to appear. A number of these plants were so marked 

 that they could be identified easily, and when the flies began to 

 appear all eggs were counted and removed. Each day, thereafter, the 

 eggs were counted and removed. 



The records of fly activity at one of the four stations were registered 

 bv these devices as follows: 



Hessian Flv Record * * * 1920, Saxdusky, Ohio 



While stations were also maintained at Bryan, Wooster and Colum- 

 bus, the brood at the last two points was much lighter and results were 

 not pronounced. For these two points, we were obHged to fall back on 



