title: Effects of a Red Marker Dye on Aedes and Culex Larvae: Are There Implications for Operational Mosquito Control?
abstract: Marker dyes are often mixed with liquid insecticide formulations prior to field applications to accurately determine the characteristics and penetration of droplets into targeted habitats. We have been using FD&C Red 40 Granular DM food dye at the rate of 20 g/liter in liquid solutions of Bacillus thuringiensis israelensis (Bti) for area-wide larvicide applications against the Asian tiger mosquito, Aedes albopictus. The Bti and dye mix ratio has been recommended by pesticide manufacturers for testing under operational conditions, but no data exist on the effects of the dye itself on mosquito larvae. We tested the effects of the FD&C Red 40 food dye in laboratory bioassays against different strains of Ae. albopictus (New Jersey and Maryland) and Culex pipiens pipiens (Utah) at rates of 0.039 to 80.0 g/liter. We also conducted field application trials to measure dye concentrations up to 100 m downwind when mixed and applied according to manufacturer instructions. In laboratory bioassays, we found that mean survival in cups with dye were significantly different from the controls beginning at 10.0 g/liter for New Jersey Ae. albopictus and at 20.0 g/liter for Maryland Ae. albopictus and Utah Cx. p. pipiens. In field application trials, we recorded a maximum volume density of 1,152.8 nl/cm(2) and calculated the maximum concentration of dye at 9.09 × 10(-3) g/liter. Our results showed that although we detected greater effects of dye on Ae. albopictus in New Jersey experiments than Ae. albopictus in Maryland and Cx. p. pipiens from Utah, concentrations of the dye during operational applications were at least 1,100 times below concentrations that exhibited toxic effects for either species in the laboratory, suggesting that the dye will not interfere with accuracy of field bioassays. Our results conclusively demonstrate that the addition of the FD&C Red 40 marker dye does not alter the efficacy of the pesticide formulation by skewing results, but rather provides a valuable addition to accurately determine pesticide penetration and spectrum by discriminating between intended pesticide and other potential pollutants.
authors.affiliation: 1  Center for Vector Biology, Department of Entomology, Rutgers University, New Brunswick, NJ 08901.|2  Mercer County Mosquito Control, West Trenton, NJ 08628.
authors.forename: Isik
authors.initials: I
authors.lastname: Unlu
authors.affiliation: 3  Ecosystem Health and Natural Resources Management Specialization, Department of Environmental Science and Technology, College of Agriculture and Natural Resources, University of Maryland, College Park, MD 20742.
authors.forename: Paul T
authors.initials: PT
authors.lastname: Leisnham
authors.affiliation: 1  Center for Vector Biology, Department of Entomology, Rutgers University, New Brunswick, NJ 08901.|4  Hudson Regional Health Commission, Secaucus, NJ 07094.
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Williams
authors.affiliation: 2  Mercer County Mosquito Control, West Trenton, NJ 08628.
authors.forename: Kim
authors.initials: K
authors.lastname: Klingler
authors.affiliation: 2  Mercer County Mosquito Control, West Trenton, NJ 08628.
authors.forename: Garrett W
authors.initials: GW
authors.lastname: Dow
authors.affiliation: 3  Ecosystem Health and Natural Resources Management Specialization, Department of Environmental Science and Technology, College of Agriculture and Natural Resources, University of Maryland, College Park, MD 20742.
authors.forename: Nicole
authors.initials: N
authors.lastname: Kirchoff
authors.affiliation: 3  Ecosystem Health and Natural Resources Management Specialization, Department of Environmental Science and Technology, College of Agriculture and Natural Resources, University of Maryland, College Park, MD 20742.
authors.forename: Sophie
authors.initials: S
authors.lastname: Jin
authors.affiliation: 5  Salt Lake City Mosquito Abatement District, Salt Lake City, UT 84116.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Delisi
authors.affiliation: 5  Salt Lake City Mosquito Abatement District, Salt Lake City, UT 84116.
authors.forename: Katherine
authors.initials: K
authors.lastname: Montenegro
authors.affiliation: 1  Center for Vector Biology, Department of Entomology, Rutgers University, New Brunswick, NJ 08901.|2  Mercer County Mosquito Control, West Trenton, NJ 08628.|5  Salt Lake City Mosquito Abatement District, Salt Lake City, UT 84116.
authors.forename: Ary
authors.initials: A
authors.lastname: Faraji
mesh_terms: D000330:Aedes / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D000818:Animals; D001391:Azo Compounds / Q000633:toxicity*; D004396:Coloring Agents / Q000633:toxicity*; D003465:Culex / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D004305:Dose-Response Relationship, Drug; D007814:Larva / Q000187:drug effects; D008396:Maryland; D009032:Mosquito Control; D009515:New Jersey; D013045:Species Specificity; D014589:Utah
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; C005915:Allura Red AC Dye
keywords: Aedes albopictus; Culex pipiens; larval mortality; low-volume larvicide; marker dye