STATE PLANT BOARD 
 
 October 1953 ET-312 
 
 United States Department of Agriculture 
 
 Agricultural Research Administration 
 
 Bureau of Entomology and Plant Quarantine 
 
 A HOMEMADE FLY TRAP 
 
 By H. M. Brundrett 
 Division of Insects Affecting Man and Animals 
 
 A fly trap made of wood and wire screening has been designed for 
 those who desire to construct their own. Soft wood that does not split 
 easily, such as redwood or white pine, is best. The screen should be 
 of Monel, bronze, or copper, and the hardware of nonrusting material. 
 
 The materials required are a piece of 24-inch screening 10 feet 
 4 inches long, the hardware listed on page 2, two pieces of 1 by 4 
 lumber 10 feet long, and 30 feet of 3/4-inch screen-door molding. One 
 of these boards is ripped slightly off center to make two different 
 widths, which are then cut into eight uprights. About 70 inches of 
 the second board is cut off, ripped into two strips of equal width, 
 and made into eight horizontals. The remainder of this second board 
 is sufficient for ripping the 1- and l/2-inch strips needed. It is 
 advisable to give all pieces of wood two coats of waterproof paint 
 before assembling them. 
 
 Four identical side panels, like the one shown in figure 1, are 
 first assembled, the lower crosspieces being 4 inches above the 
 lower ends of the uprights. Half-lap joints are used held together 
 with 2d nails. Screening is tacked to the inside of the frame, and 
 the edges are covered with molding. The four panels are then fastened 
 together with screws. An 18- by 18-inch frame with screening is then 
 screwed to the top edge of the cage, and the cone is constructed and 
 installed. 
 
 The cone is made from one piece of screening. A pattern should 
 be first made of paper (fig. 2). A semicircle is drawn with a radius 
 of 22 inches, and radii are drawn from the center to points on the 
 circumference 15 inches apart, making four equal triangles. A 1/2- 
 inch lap is left along one margin. When the screening has been cut 
 to the desired shape, it is rolled into a cone and the lap is soldered 
 to the opposite edge. The screening may be held in position for 
 soldering by tacking it lightly to the edge of a 1 by 4. Although 
 soldering is preferred, the edges can be either laced together with 
 copper wire or nailed to a strip of wood. 
 
The four pieces for the cone frame are nailed together to form a 
 square. Then the screening is tacked to the inside of the frame, and 
 the edges are covered with screen-door molding. The apex of the 
 cone is cut off to leave an opening about 1 inch in diameter. The cone 
 is slipped into position and fastened with L-head screws (fig. 3), or it 
 may be held in place by means of two small turn buttons if preferred. 
 
 A good bait pan to use with a trap of this size is one 14 inches 
 wide and 4 1/2 inches high. Granite-covered iron is very durable if 
 handled carefully so that the granite is not broken. The pan should 
 fit loosely inside the cone frame and extend 1/2 inch above the bottom 
 edge of the trap. 
 
 The bait to use depends upon the kind of fly to be trapped. For 
 blow flies an excellent attractant is 2 pounds of beef liver in 1 gallon 
 of water. For house flies 2 pounds of brown sugar, or 1 pint of cane 
 molasses, in 1 gallon of water may be used. After several days' 
 fermentation the bait becomes more attractive. 
 
 Best results are obtained when the trap is installed in the open 
 with no tree branches or other obstructions directly above it (fig. 4), 
 Partial shade does not harm the catch materially in hot weather, but 
 in cold weather the trap should be placed out of the wind but exposed to 
 sunlight. 
 
 Materials 
 
 Number 
 
 4 Uprights for panel frame 
 4 do 
 
 8 Horizontals for panel frame 
 
 4 Frame for top 
 
 4 Frame for cone 
 
 8 Molding for panel, verticals 
 
 4 Molding for panel, horizontals 
 
 4 Molding for cone 
 
 4 Screening (sides) 
 
 1 Screening (top) 
 
 1 Screening (cone) 
 
 1 l/4-lb. box of wire nails (for molding) 
 
 4 Cement-coated nails for cone frame 
 
 80 Galvanized nails for lap joints 
 
 1 l/4-lb. box of canvas tacks 
 
 16 Flat-headed wood screws for panels 
 
 8 Flat-headed wood screws for top 
 
 2 L-head screws 
 
 String solder, rosin core 
 
 2 1/16 X 3/4 X 28 
 1 5/16 X 3/4 X 28 
 
 1 11/16 X 3/4 X 17 1/4 
 1/2 X 3/4 X 1 7 1/4 
 1x3/4x15 5/8 
 
 20 1/2 inches long 
 15 1/2 inches long 
 
 14 5/8 inches long 
 
 15 1/2 x 22 
 18 X 18 
 24 X 44 
 3/4 X 18 
 6d 
 
 2d 
 
 11/2x8 
 11/4x7 
 
 2 inches long 
 
Figure l.--Side panel 
 of fly trap. 
 
 Figure 2. --Pattern for screen cone. 
 
UNIVERSITY OF FLORIDA 
 
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 3 1262 09242 9488