We assessed the exposure and acute toxicity of naled, applied aerially as an ultra-low-volume spray for mosquito control, on late instar larvae of the Miami blue (Cyclargus thomasi bethunebakeri) (Comstock and Huntington 1943) (Lepidoptera: Lycaenidae), an imperiled South Florida butterfly. We concurrently evaluated the control efficacy against caged adult female salt-marsh mosquitoes (Aedes taeniorhynchus) (Wiedemann 1821) (Diptera: Culicidae). This 3-yr study was conducted in north Key Largo (Monroe County, FL) beginning in 2006. The field trials incorporated 15 sampling stations: nine in the target spray zone, three in the spray drift zone at varying distances from the target zone, and three in the control zone not subjected to naled spray drift. A total of six field spray trials were completed, three at an altitude of 30.5 m (100 feet), and three at 45.7 m (150 feet). For all trials, the ultra-low-volume application of Trumpet EC insecticide (78% naled) at a rate of 54.8 ml/ha (0.75 fl. oz/acre) was effective in killing caged adult mosquitoes in the target zone. Butterfly larvae survival was significantly reduced in the spray zone compared with drift and control zones. Analysis of insecticide residue data revealed that the mortality of the late instar butterfly larvae was a result of exposure to excess residues of naled. Additional research is needed to determine mitigation strategies that can limit exposure of sensitive butterflies to naled while maintaining mosquito control efficacy.

A study was conducted to evaluate the impact of naled on honey bees as a result of their exposure to aerial ULV applications of this insecticide during three routine mosquito spray missions by Manatee County Mosquito Control District in Florida during the summer of 1999. Naled deposits were collected on filter paper and subsequently analyzed by gas chromatography. Mortality of adult honey bees Apis mellifera L. was estimated based on numbers from dead bee collectors placed in front of the entrance of the beehives. We found that honey bees clustering outside of the beehives were subject to naled exposure. Bee mortality increased when higher naled residues were found around the hives. The highest average naled deposit was 6,227 +/- 696 microg/m2 at the site 1 forest area following the mosquito spray mission on July 15, 1999. The range of naled deposition for this application was 2,818-7,101 microg/m2. The range of dead bees per hive was 0-39 prior to spraying and 9-200 within 24 h following this spray mission. The average yield of honey per hive was significantly lower (p < 0.05) for naled-exposed hives compared with unexposed hives. Because reduction of honey yield also may be affected by other factors, such as location of the hives relative to a food source and vigor of the queen bee, the final assessment of honey yield was complicated.

The impact of the mosquito adulticide naled on honey bees, Apis mellifera L., was evaluated by exposing test beehives to nighttime aerial ultra-low-volume (ULV) applications using a high-pressure nozzle system. The tests were conducted during routine mosquito control missions at Manatee County, Florida, in summer 2000. Two treatment sites were sprayed a total of four times over a 10-wk period. Honey bees, which clustered outside of the hive entrances, were subjected to naled exposure during these mosquito control sprays. The highest average naled ground deposition was 2,688 microg/m2 at the Port Manatee site, which resulted in statistically significant bee mortality (118) compared with the controls. At the Terra Ceia Road site, an intermediate level of naled deposition was found (1,435 microg/m2). For this spray mission, the range of dead bees per hive at Terra Ceia was 2 to 9 before spraying and 5 to 36 after naled application. Means of all other naled ground depositions were < 850 microl/m2. We concluded that substantial bee mortality (> 100 dead bees) resulted when naled residue levels were > 2,000 kg/m2 and honey bees were clustered outside of the hive entrances during mosquito adulticide applications. Compared with the flat-fan nozzle systems currently used by most of Florida's mosquito control programs, the high-pressure nozzle system used in this experiment substantially reduced environmental insecticide contamination and lead to decreased bee mortality. Statistical analysis also showed that average honey yield at the end of the season was not significantly reduced for those hives that were exposed to the insecticide.

A Bacillus sphaericus highly toxic to 4th-stage Culex quinquefasciatus was isolated from sediment samples collected at Winter Beach marsh in Indian River County, Florida. This isolate, named WBM 1-1-13, showed significantly higher toxicity compared with strain 2297. WBM 1-1-13 is equivalent, though better initially, to the toxicity of strain 2362, the active ingredient of VectoLex. Furthermore, the Winter Beach marsh isolate produced more Bin per unit medium than strain 2362, which suggests that this new isolate could be useful for Culex control.