Fly Bait Recipes

Liquid Yeast Bait

(from Satrom and Stephens 1979)

This recipe makes 7-9 portions of liquid bait for use with a cone trap. It can be stored 20-30 days once it is ready for use.

2 quarts tepid (not hot) water (95-105 F)
1 cup + 3 oz. active dry yeast (baking yeast)
2 tablespoons ammonium carbonate (optional*)

*Ammonium carbonate is available from chemical supply houses and will improve the odor of the bait.

Mixing the bait

Use a plastic (not glass) narrow-necked gallon jug with a screw cap for mixing, ripening, and storing bait. Bleach or milk jugs work well. Wide-mouth containers will not produce effective bait.

Mix all the above ingredients in the jug. Important: With cap lightly sealed, allow mixture to begin to ripen (see ripening instructions below). It will foam up at first. After it subsides (1-2 days), tighten the lid and continue ripening till very smelly (2-9 additional days). Gases must escape while bait is foaming up (loose cap), but bait must finish ripening without air (tight cap) to attract flies.

Ripening the bait:

Allow bait to ripen 4-10 days in a place where temperatures remain above 60 F during the night and day. Bait is ripe when it is very smelly, with a musky, penetrating odor. Warm daytime temperatures will make up for slightly cooler (less than 60 F) nights, but in general, the warmer the average temperature, the faster the bait will ripen. Because of its heavy odor, the bait should be ripened in a well-ventilated area where it will not offend people. Do not ripen or store the bait in direct sunlight. Extreme temperatures can build within the jug, kill the yeast, and cause gases to expand enough to pop off the lid or break the jug.

Storing the bait:

To maintain potency, store bait with the cap kept tight. Open the jug only when necessary to refill the bait pan. Do not store in direct sunlight.

Note: Ripened bait should be treated as a decaying food material. It can cause gastro-intestina disturbances if ingested.

Using the bait:

Stir or shake the bait supply each time before adding to the bait pan. Pour about 1 cup (8 ounces) of bait in a wide pan on a level surface under the trap. Be sure the edge of the pan is higher than the bottom edge of the trap frame.

The bait is effective in the pan for at least 3 to 5 days. It attracts more flies on the first day, and then gradually declines thereafter. Don't let the bait dry out.

Beltsville Bait

(from Pickens, et al. 1994)

This makes a dry bait that can be easily stored for a considerable time. It must be mixed with water before using.

1 pound granulated sugar
1 pound baking powder (double-acting type)
2 ounces dry active yeast (baking yeast)
6 ounces air-dried blood or freeze-dried fish meal
1/4 cup honey
2 tablespoons* water

*Quantity of water needed may vary with humidity of air when mixing. Use only sufficient water to bind dry ingredients together when they are compressed.


Mix ingredients thoroughly. Press mixture into a plastic ice-cube tray to form cubes. Invert the tray to dump the cubes, and let them dry to form hard blocks. To use the bait, add 2 cubes of bait to 2 quarts of water. Place bait in a wide-mouth pan beneath a cone-type trap. Flies are attracted to this bait from only a short distance, so traps should be placed within 6 feet of areas where flies are active. Bait pans should be cleaned and baited every 1 to 2 weeks and should be kept filled with water.