Attractants for House Flies

Christopher J. GedenUSDA, ARS, CMAVE

Howard (1911) described a prototype baited trap developed by C F. Hodge

Methods: ”…baited with fish heads, meat scraps, watermelon rinds, and green corncobs, over which the melted waste from the ice cream freezer was poured”

Results: “on one occasion he caught 2,500 flies in fifty-five minutes”

• In 1945, Harvey Scudder was assigned by the US Public Health Service to assess of the efficacy of DDT.• No standard methods had been developed for measuring fly populations at the time.• His solution: count flies resting on a known surface area, making 3-5 counts in areas appearing to have the highest population. (Scudder, H. I. 1947 A new technique for sampling the density of housefly populations)

“In constructing a neutral resting surface, consideration has been given to the fact that houseflies are commonly observed to select edges as resting places” Scudder 1947.

The Scudder grid (or grill) became the standard method for monitoring house fly populations for many years, and is still the method of choice for some organizations.• World Health Organization • U.S. Armed Forces Pest Management Board • California Integrated Waste Management Board

Advantages: • Simple• Inexpensive• Fast• Allows sampling of many sites• If used consistently, can be used to measure population changes over time

Action thresholds proposed by Scudder (1998)_______________________________Location No. flies/grill_______________________________Restaurant kitchen 2Residential back yard 2-3City block 5Milking parlor 15General farm 20_______________________________

Scudder, H. I. 1998. Use of the fly grill for assessment of house fly populations: An example of sampling techniques that create rough fuzzy sets. J. Vector Ecol. 21: 167-172.

Axtell (1970) introduced the spot card and recommended its use as a fly monitoring tool.

Advantages: • Easy• Inexpensive • Allows consistent sampling of the same locations over time• Measures activity over a week rather than giving snapshot of instantaneous fly activity• Good tool for monitoring fly populations indoors

Disadvantages: does not distinguish among fly species; temperature dependent

Research on fly attractants led to improvements over food-baited “Big Stinky” types of traps.

Mulla (1970’s) identified triemethylamine and indole/skatole as potent feeding attractants.

Carlson (1970’s) discovered the pheromone (Z)-9-tricosene

Scatter baits including some or all of these components plus fast-acting toxicants were a major improvement over earlier insecticidal baits.

The challenge: attractant must compete with natural odors

Olson sticky cylinder trap with white sleeve

Farnam Fly Terminator

Victor Fly Magnet

Sheltered QuikStrike with collecting pan

Comparison of Olson sticky trap, Farnam jug trap, Victor jug trap, and sheltered QuikStrike bait strip stations.__________________________________________________Day Olson Farnam Victor QuikStrike__________________________________________________ Mean no. house flies/trap 1 661 b 5,462 a 2,920 a 6,015 a 2 679 c 4,356 b 2,934 bc 8,814 a 3 678 c 3,080 b 2,520 bc 7,366 a 4 515 b 904 b 1,611 b 5,659 a__________________________________________________Means within rows followed by the same letter are not significantly at P=0.05 (Tukey’s range test)

Comparison of Olson sticky trap, Farnam jug trap, Victor jug trap, and sheltered QuikStrike bait strip stations.__________________________________________________Day Olson Farnam Victor QuikStrike__________________________________________________ % Females 1 21.9 c 72.1 a 59.1 ab 47.5 b 2 19.8 c 73.8 a 78.0 a 35.2 b 3 19.8 c 62.2 ab 68.2 a 46.2 b 4 15.9 d 66.5 b 76.8 a 41.0 c__________________________________________________Means within rows followed by the same letter are not significantly at P=0.05 (Tukey’s range test)

Jug traps and QuikStrike vs sticky traps.

RESULTS: • Sheltered QuikStrike bait stations collected more flies than the other methods. • Jug traps collected higher proportions of female flies flies (66-78%) than QuikStrike stations (35-48%) or sticky traps (16-22%). • Jug trap counts on day 4 were much lower than on day 1. • All of the methods except the QuikStrike stations were limited by trap saturation effects.

Effect of “fly conditioning” on attractiveness of Farnam attractant. ________________________________________________

Day No. flies collected : % Females Fresh Fly-conditioned Fresh Fly-conditioned________________________________________________ 1 7,953 a 8,149 a 90.9a 33.0 b 2 6,762 a 3,337 ab 75.9 a 60.2 b 3 4,749 a 2,429 ab 78.5 a 57.0 b 4 994 a 706 a 64.7 a 66.8 a________________________________________________Means within rows under subheading followed by the same letter are not significantly at P=0.05 (Tukey’s range test)

Do jug trap collections increase when attractant is “fly-conditioned”?

RESULTS: No. Fly-conditioned attractant collected about the same number of total flies as fresh attractant, but proportionally more females were collected with fresh attractant.

Comparison of traps baited with Farnam attractant, Victor attractant, or a combination.________________________________________________

Day Farnam Victor Farnam + Victor________________________________________________ Mean (SE) no. flies collected 1 469 b 1,279 ab 2,295 a 2 2,631 b 2,114 b 6,847 a 3 2,457 b 2,030 b 6,812 a 4 1,037 b 1,059 b 3,662 a ________________________________________________Means within rows followed by the same letter are not significantly at P=0.05 (Tukey’s range test)

Are the Farnam and Victor attractants synergistic?

RESULTS: Yes. Attractant combinations collected significantly more flies than either attractant alone and more than expected based on the sum of the collections in the two single-attractant treatments.

Comparison of molasses (25% diluted blackstrap), standard Farnam Terminator attractant, & molasses plus Farnam attractant. ________________________________________________Day Molasses Farnam Molasses + Farnam________________________________________________

Mean no. house flies/trap 1 6,251 a 9,835 a 8,588 a 2 4,407 a 6,946 a 7,021 a 316,417 a 19,378 a 16,053 a 4 8,895 a 13,778 a 10,347 a ________________________________________________Means within rows followed by the same letter are not significantly at P=0.05 (Tukey’s range test)

Molasses as a fly attractant.

RESULTS: Molasses traps collected as many flies as traps with Farnam attractant or molasses-attractant mixtures.

Farnam attractant: The two main components are metabolic products of protein degradation that provide flies with token stimuli for the presence of protein. The attractant has a very objectionable odor and can not be used near people or food.

Molasses is a complex material that may contain sugar breakdown products to provide flies with token stimuli for the presence of sugars.

Quinn, B. et al. 2007. Analysis of extracted and volatile components in blackstrap molasses feed as candidate house fly attractants. J. Chromatography, Series A. (in press).

Organic components extracted from blackstrap molasses __________________________________________________________________ Compound name Retention time (min) Found in extract __________________________________________________________________ dihydro-2-methyl-hydroxy-2(3H) furanone 11.59 hexane x 3-hydroxy-2-butanone 11.96 ether 2,5-dimethylpyrazine 12.69 ether x trimethylpyrazine 13.82 ether x acetic acid 14.41 both propionic acid 15.45 both x butanoic acid 16.86 both x furfuryl alcohol 17.16 both x pentanoic acid 18.14 hexane propanamide 18.84 ether x 2-hydroxy-3-methyl-2-cyclopenten-1-one 19.08 both x hexanoic acid 19.34 ether 2,5-dimethyl-4-hydroxy-3(2H) furanone 19.44 both butylated hydroxy-toluene 19.92 ether acrylamide 20.22 ether x 1-(1H-pyrrol-2-yl) ethanone 20.63 both x furan carboxylic acid methylethyl ester 21.04 hexane 2(3H)-dihydro-3-hydroxy-4,4-dimethyl furanone 21.26 ether x 5-acetyldihydro-2(3H) furanone 21.59 ether 2-methoxy-4-vinylphenol 22.79 both 5,6-dihydro-6-pentyl-2H-pyran-4-one 23.17 hexane 2,6-dimethoxyphenol 23.41 both x 1-acetyl pyrrolidine 24.43 ether 2,3-dihydrobenzofuran 24.55 ether 1,4:3,6-dianhydro-α-d-glucopyranose 24.63 ether benzoic acid 25.20 both x 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline 25.37 both benzeneacetic acid 26.14 both x dihydro-4-hydroxy-2(3H) furanone 26.32 ether 1-(4-hydroxy-3-methoxyphenyl) ethanone 26.62 both x 1-(4-hydroxy-3-methoxyphenyl)-2-propanone 26.74 both x 2,6-dimethoxy-4-(2-propenyl)-phenol 27.27 both 3,4-dimethoxyphenol 27.54 both 4-(4-hydroxy-3-methoxyphenyl)-2-butanone 27.81 hexane hexadecanoic acid 28.52 hexane 3-(2-hydroxyphenyl)-2-propenoic acid 28.62 hexane 4-methoxybenzoic acid 28.68 hexane x 4-hydroxy-9-fluorenone 28.89 hexane 4-hydroxybenzaldehyde 29.07 ether x 4-pyridinecarboxamide 29.18 ether x 4-hydroxy-3-methoxybenzene acetic acid 29.22 ether 1-(4-hydroxy-3,5-dimethoxyphenyl) ethanone 29.35 hexane

From this information, we developed several candidate blends of components. A 7-component blend looks particularly promising…

Fly response to blend in assay chambers

View collections after 5-min assay period

Responses of house flies to 7 component molasses blend in outdoor cages _______________________________________________ Fly count Blend Water control _______________________________________________ 1 min counts 26.3 (5.1) 6.7 (2.2) 3 min counts 21.5 (2.7) 5.7 (1.6) 5 min counts 15.2 (2.6) 6.3 (1.3) Collection at 5 min 69.5 (22.2) 5.8 (3.9) ________________________________________________ “Counts” are visual counts of flies resting on the outside cover of the assay chamber at 1, 3 and 5 minutes after placement in the cages. At the end of 5 minutes, the entry port was sealed and the flies present in the assay chamber were counted.

Jug trap tests, CMAVE tents: _____________________________ Water Farnam MolBlend _____________________________ Tent 1 41 71 206 Tent 2 30 121 235 Tent 3 42 65 227 Mean 37.7 85.7 222.7 _____________________________

Jug trap tests, CMAVE tents: ______________________________ Rep Water 25% Mol. MolBlend ______________________________ 1 62 118 189 2 23 88 303 3 64 165 453 Mean 49.7 123.7 315.0 ______________________________

Jug trap tests, CMAVE tents _______________________________________ Tent Water 25% Mol. MolBlend Farnam _______________________________________ 1 58 264 422 191 2 46 442 347 303 3 72 353 855 188 Mean 58.7 353.0 541.3 227.3 _______________________________________

How well will the blend compete with other natural food odors?

Can the lure be incorporated into an attract-and-kill system?