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ARS Home » Plains Area » Kerrville, Texas » Knipling-Bushland U.S. Livestock Insects Research Laboratory » Livestock Arthropod Pest Research Unit » Research » Publications at this Location » Publication #397697
Research Project: Integrated Pest Management of Flies of Veterinary Importance

Location: Livestock Arthropod Pest Research Unit

Title: A new formulation of screwworm attractant with reduced hazardous chemicals and transport restrictions

Author
item Hickner, Paul
item PACHECO, LUCAS - ANIMAL AND PLANT HEALTH INSPECTION SERVICE (APHIS)
item Duke, Sara
item SANCHEZ ORTIZ, CARLOS - ANIMAL AND PLANT HEALTH INSPECTION SERVICE (APHIS)
item WELCH, JOHN - ANIMAL AND PLANT HEALTH INSPECTION SERVICE (APHIS)
item PHILLIPS, PAMELA - ANIMAL AND PLANT HEALTH INSPECTION SERVICE (APHIS)
item Arp, Alex

Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/12/2023
Publication Date: 4/20/2023
Citation: Hickner, P.V., Pacheco, L., Duke, S.E., Sanchez Ortiz, C., Welch, J.B., Phillips, P.L., Arp, A.P. 2023. A new formulation of screwworm attractant with reduced hazardous chemicals and transport restrictions. Journal of Medical Entomology. https://doi.org/10.1093/jme/tjad043.
DOI: https://doi.org/10.1093/jme/tjad043

Interpretive Summary: New World screwworm flies, Cochliomyia hominivorax (Coquerel), develop in the tissues of living, warm-blooded animals, including cattle. Due to the serious economic damage inflicted on the livestock industries, they were eradicated from North and Central America during the mid-20th to early-21st centuries using the sterile insect technique (SIT), a method presently employed to maintain a permanent barrier between Central and South America. Attractive baits/lures are an important component of the screwworm eradication program, where they are used for surveillance, sample collection, and strain evaluation in the field. The first chemical lure, later named swormlure, was developed based on the attractiveness of C. hominivorax to odors produced from decomposing animal tissues. The formulation has changed little over the years and presently contains 10 chemicals, one of which is dimethyl disulfide (DMDS). Restrictions on the transport of DMDS have recently impeded its use in swormlure-4 (SL-4). However, dimethyl trisulfide (DMTS) is not as highly restricted and can be shipped via air transportation. Both chemicals are produced by microbial decomposition of animal tissues. Here, we conducted field trials using three releases of sterile C. hominivorax, each comprising approximately 93,000 flies, to test the efficacy of SL-4, containing DMDS, to swormlure-5 (SL-5) containing DMTS. Traps baited with SL-4 and SL-5 were similar in attraction to C. hominivorax, but, SL-5 was considerably more attractive to Cochliomyia macellaria (Fabricius), a closely related but non-target fly.

Technical Abstract: New World screwworm flies, Cochliomyia hominivorax (Coquerel), are obligate parasites of warm-blooded animals. Due to the serious economic damage inflicted on the livestock industries, they were eradicated from North and Central America during the mid-20th to early-21st centuries using the sterile insect technique (SIT), a method presently employed to maintain a permanent barrier between Central and South America. Lures are an important component of the screwworm eradication program, where they are used for surveillance, sample collection, and strain evaluation in the field. The first chemical lure, later named swormlure, was developed based on the attractiveness of C. hominivorax to volatile organic compounds (VOCs) produced from decomposing animal tissues. The formulation has changed little over the years and presently contains 10 chemicals, one of which is dimethyl disulfide (DMDS). Restrictions on the transport of DMDS have recently impeded its use in swormlure-4 (SL-4). However, dimethyl trisulfide (DMTS) is not as highly restricted and can be shipped via air transportation. Both chemicals are produced by microbial decomposition of animal tissues. Here, we conducted field trials using three releases of sterile C. hominivorax, each comprising approximately 93,000 flies, to test the efficacy of SL-4, containing DMDS, to swormlure-5 (SL-5) containing DMTS. Traps baited with SL-4 and SL-5 captured 575 (M = 191.7, SD 17.9) and 665 (M = 221.7, SD 33.2) C. hominivorax, respectively (P = 0.241). However, SL-5 was considerably more attractive to Cochliomyia macellaria (Fabricius), a closely related but non-target fly.