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Acute toxicity and persistence of three insect repellents, deet and two piperidines (AI3-35765 and AI3-37220), were evaluated against mosquito larvae of Aedes albopictus (Skuse) and Anopheles albimanus Wiedemann (Diptera: Culicidae) in the laboratory, and against natural populations of Ae. albopictus in the field. In laboratory studies, the LC50 values of the repellents for first instars ranged between 0.005 and 0.021% (Ae. albopictus) and between 0.01 and 0.014% (An. albimanus) and, for fourth instars, between 0.019 and 0.034% (Ae. albopictus) and between 0.015 and 0.024% (An. albimanus). A 0.1% concentration of deet caused 90-100% mortality in first-instar Ae. albopictus for 4 weeks, whereas AI3-35765 and AI3-37220 at the same concentration killed 95-100% of larvae for 12 weeks and 98-100% of larvae for 33 weeks post-treatment, respectively. Deet and AI3-35765 at 0.1 % concentration resulted in complete mortality of first-instar An. albimanus for 3 weeks post-treatment, whereas AI3-37220 resulted in 91-99% larval mortalities for 35 weeks post-treatment. A 0.1% concentration of A13-37220 provided 77-98% larval mortality for 20 weeks and 63-97% larval mortality for 12 weeks post-treatment, respectively, against fourth-instar Ae. albopictus and An. albimanus. In the field, in artificial containers, the reduction of Ae. albopictus larvae caused by deet, AI3-35765 and AI3-37220 was 88-95% for 3-4 weeks, 98-100% for 7 weeks, and 82-100% for 13 weeks post-treatment, respectively. In used tyres, the same concentration of the repellents resulted in 100% reduction of Ae. albopictus larvae for 2 weeks (deet), 4 weeks (AI3-35765) and 5 weeks (AI3-37220) post-treatment. In cemetery flower vases, Aedes spp. larvae were eliminated for 4 weeks (deet) and 6 weeks post-treatment by both A13-35765 and AI3-37220. These topical repellents (particularly AI3-37220) have good potential for development and use in the management of container-inhabiting mosquitoes because they deter oviposition and kill larvae.

Seven microorganisms including 4 protozoans, 2 fungi, and a bacterium infected Aedes albopictus (Skuse) larvae collected from 12 counties in northecentral Florida. Ae albopictus and 14 other species of mosquitoes were collected from tires, flower-holding vases in cemeteries, other types of artificial containers, and treeholes. Ascogregarina taiwanensis (Lien & Levine) was the most common parasite of Ae. albopictus throughout the year. The microsporidium Vavraia culicis (Weiser) infected Aedes aegypti (L.), Ae. albopictus, Aedes triseriatus (Say), and Orthopodomyia sinifera (Coquillett). A vibrio bacterium and 2 fungi (Leptolegnia sp. and Smittium culisetae Lichtwardt), infected Ae. albopictus larvae but were observed infrequently. A. taiwanensis, S. culisetae, and the vibrio bacterium previously have been reported from Ae. albopictus. This is the 1st report of the other 4 microorganisms parasitizing Ae. albopictus larvae.

We compared rates of feeding on human hosts for blood-engorged female Anopheles quadrimaculatus species A, B and C1 collected from daytime resting sites in Manatee Springs State Park, Levy County, Florida during 1992-1993. Quick-blot DNA probes were used to identify mosquito taxa and also the presence of human blood in the mosquito gut. In collections from a campground area, human blood-feeding rates differed significantly among mosquito species (10.7% [19 of 177], 0%, [0 of 62], and 1.2%, [4 of 327]), respectively for species A, B and C1). In collections from a woodland site (1 km from the campground), 1.5% (2 of 129) of the species B females had fed on humans, whereas none of 19 species A or 159 species C1 females had done so. Of the three species in this study area, species A appears the most likely to be a biting pest of humans and a vector of human malaria.

Anopheles perplexens was collected from habitats previously unreported for this species in northern Florida. These habitats included intermittently flooded swamps, water-filled tires, and plastic oviposition cups. First-instar An. perplexens larvae were recovered from soil samples collected in an intermittently flooded swamp that were flooded in the laboratory, suggesting that An. perplexens eggs may survive in the soil during dry periods. Anopheles perplexens larvae were collected from water-filled tires and plastic oviposition cups at sites near Gainesville, FL. Of 30 dissected An. perplexens females collected in updraft CDC traps, all had ovarioles in Christophers's stage II and blood was absent in the midgut. The physiological state of these females indicates that updraft CDC traps collect predominately host-seeking females and that females take one blood meal per gonotrophic cycle.

We compared the number of Aedes albopictus and Aedes aegypti females collected in CDC, duplex cone, bi-directional Fay, and new omni-directional traps in a series of trials in northern Florida during 1992 and 1993. Bi-directional Fay and omni-directional traps collected significantly more Ae. albopictus females than did the other traps tested. The bi-directional Fay trap collected significantly more Ae. aegypti females than did any other trap. The results of these studies indicate that these traps may be useful tools for sampling Ae. albopictus and Ae. aegypti adults.

Updraft CDC traps baited with dry ice were used to monitor changes in the abundance and parity rate of Anopheles quadrimaculatus Say complex mosquitoes in an intermittently flooded swamp in Central Florida during an 18-d period. Mosquitoes collected each day were identified to species using DNA hybridization and isozyme electrophoretic techniques and were dissected to determine follicular maturation and parity. Of 1,178 An. quadrimaculatus mosquitoes identified to species, 4% were species A and 96% were species C. Dissections of females of both species indicated that 98% were nonblood fed and nongravid with ovariole development at Christophers' stage II. Overall parity rates were 0.19 and 0.51 for populations of species A and species C, respectively. The duration of the gonotrophic cycle for species C females was estimated to be 5 d based on the interval between peaks in the number of nulliparous females collected on days 1 and 6 and peaks in the number of parous females collected 5 d later. Significant trends were observed in the number of parous species C females collected each day, indicating that the parity rate could not be used as an unbiased estimator of survivorship.