The cage described requires only two lengths of pipe — 6-foot 10-inch posts and 

 10-foot frame rails. These lengths can be cut with a minimum of waste from standard 

 21-foot pipe lengths. It is best to remove the threaded end of the pipe, even though this 

 operation necessitates one additional cut for each 21-inch length of pipe. 



Inexperienced help can make any number of time-consuming mistakes. One 

 supervisor thoroughly familiar with the details should not attempt to direct more than 

 two inexperienced helpers. Erection and dismantling of the cage can be accomplished 

 by a crew of three in approximately 2 days — 1 day for the framework and 1 day for the 

 covering — or a total of 6 man-days to erect and 6 to dismantle the cage. A sloping 

 terrain and other situations may double the labor required. 



The No. 5 tees could be improved if the Allen setscrews were on the side rather 

 than on the base. The setscrews in the standard fittings require that the ground rails 

 be lifted and the screws tightened blindly by feel. It is important that the ground rails 

 be centered in the tees and firmly attached by setting the Allen screws during the initial 

 layout of the framework and before the anchor stakes are driven. 



Tightening the Allen screws on a 7-foot-high cage is a little awkward. Light 

 platforms constructed of brazed ^-inch conduit frames with a wooden top were made to 

 elevate the men working on the frame. 



The 20-mesh Saran screen enclosing such a large area had no effect on the 

 temperature or humidity within the cage. It did depress the light 50 percent and 

 caused the plants to grow rank. The cage was constructed 7 feet high to give maximum 

 freedom for bee flight and to cover a crop such as sweetclover, which was used in 

 1962. 



FIBERGLASS SCREEN CAGES 



Two smaller cages, 24 feet 8 inches by 133 feet, with 8- and 12-mesh fiberglass 

 screening, were constructed in 1962 to determine the effect of light on the activity of 

 the bees and the physiology of the plants in regard to pollination and seed set. Fiber- 

 glass screening appears to have the structural strength and durability equal to the 

 Saran screening and is much lighter in weight, even considering the differences in 

 mesh. Costs are competitive between the two types of materials. The 8-mesh costs 

 considerably less than the 12-mesh fiberglass or the 20-mesh Saran. 



Panels for these cages were sewn 8 feet 4 inches wide and 33 feet 4 inches long 

 to permit use of 100-inch Government surplus zippers and to fit the cages to the 

 planted field of sweetclover. For these dimensions two odd lengths of pipe were 

 required — 4-foot 4-inch cross pipes and 3-foot end pipes. Otherwise the framework 

 was identical to that of the larger Saran screen cage. 



