Long-Term Insect Repellent Electrospun Microfibers from Recycled Poly(ethylene terephthalate).

In recent years, there has been an increase in the incidence of insect-borne diseases. Topically applied insect repellents are used to prevent these infectious diseases, but concerns of skin permeability and rapid evaporation rates have made way for alternative preventative methods. Encapsulation of insect repellents in polymeric materials allows for nonskin contact methods of repellent delivery with extended-release profiles without the need for reapplication. Poly(ethylene terephthalate) (PET) is widely used in textiles as well as food packaging and other single-use applications. This short product lifespan makes PET a major environmental pollutant; thus, recycling of PET is of great interest and utility. We report on the fabrication and evaluation of recycled PET microfibers containing N,N-diethyl-meta-toluamide (DEET) and picaridin and the first evaluation of dual repellent loading (DEET/picaridin) via electrospinning. The electrospun microfibers displayed a repellent retention up to 97% within the polymer network upon processing. Release profiles were characterized by isothermal thermogravimetric analysis (TGA). Hansen solubility parameters correlated release profiles with the chemical affinity between PET and the repellent substrate. Insect repellency was assessed against live mosquitoes using a novel bioassay method. Repellency was observed to be as high as 100% for over 1 week and 80% for over 3 weeks. Our method allows for long-lasting repellency with the potential for large-scale textile manufacturing.

Evaluation of various substances and trap component configurations to increase mosquito collections in Biogents Gravid Aedes traps.

Two independent studies were conducted in northeastern Florida to determine if Biogents Gravid Aedes Trap (GAT) mosquito collections could be enhanced with a variety of substances and structural configurations. The first study baited GATs with either: 1) an infusion of mixed Southern live oak leaf (Quercus virginiana) and slash pine needle (Pinus elliottii) litter, 2) Biogents Lure (BG Lure), 3) yeast-derived carbon dioxide), 4) yeast-derived carbon dioxide+ BG Lure, or 5) a combination of all three. Nine mosquito species were collected from traps in the first study with Psorophora ferox>Culex nigripalpus>Aedes aegypti>Cx. quinquefasciatus as the top four most abundantly collected species. No significant difference in mosquito abundance was observed among these species among treatments. However, when the overall number of mosquitoes for all nine species was pooled, GATs baited with the combination of yeast-derived carbon dioxide + BG Lure + leaf infusion numerically collected the greatest number of individuals compared with the other four treatments. The second study evaluated the separate and combined attractiveness of individual GAT structural components/configurations with and without Southern live oak leaf litter infusion and BG-Lure. Aedes albopictus, Ae. aegypti, Anopheles quadrimaculatus, and Cx. quinquefasciatus were collected from all these traps in the second study. Results generally revealed that the current commercially available GAT configuration consisting of a screened translucent top (with BG-Lure) fitted into the black reservoir baited with oak leaf infusion remained the most attractive combination for collecting northeastern Florida mosquitoes.

Potential of Outdoor Ultra-Low-Volume Aerosol and Thermal Fog to Suppress the Dengue Vector, Aedes aegypti, Inside Dwellings.

A field study investigated penetration of outdoor ground ultra-low-volume (ULV) aerosol and thermal fog adulticide applications into a dwelling to control the dengue vector Aedes aegypti (L). Four applications of Kontrol 4-4 (4.6% permethrin active ingredient [AI], 4.6% piperonyl butoxide) at the maximum label rate were made at 25-30 m in front of a house at Camp Blanding Joint Training Center, Starke, FL, during summer 2016. The ULV sprayer and thermal fogger nozzles were oriented horizontally, and vehicle travel speeds were 16 and 24 km/h, respectively. All doors and windows of the house were left open. Spray efficacy was assessed using caged female mosquitoes positioned 30 cm above ground, outside and inside of the house. Interior cages were placed in open areas and cryptic sites (i.e., in a closet or cardboard box). A spinner holding 2 rods sized 3 mm × 75 mm was deployed next to each cage (except cryptic sites) to sample droplets and to quantify AI deposition. Thirty minutes after application, cages were removed, slides collected, and mosquitoes transferred to clean cages in the laboratory where mortality was assessed at 24 h posttreatment. The ULV application to the south side of the house produced 100% mortality in outdoor and indoor cages and 24% mortality at cryptic sites. Similarly applied thermal fog resulted in 85% mortality outdoors, 34% indoors, and only 4% in cages at cryptic sites. Application of either method from the west resulted in 19-61% mortality outdoors and 0.5-6.5% indoors. Droplet volume median diameter (Dv0.5) on rods from the ULV application was significantly larger compared with the thermal fogger outdoors, but similar indoors. Outdoors and indoors, the AI deposition from ULV was significantly higher than from thermal fog. Our results show the potential for controlling dengue vectors inside houses with outdoor ground ULV applications in areas where doors and windows are left open for ventilation.

Evaluation of the DynaTrap Flylight (DT-3009) Against House Flies and Stable Flies (Diptera: Muscidae) Under Indoor Conditions.

Ultraviolet light traps are commonly used to manage house flies in indoor situations. Many indoor traps are longer than their 46-cm fluorescent tubes and have glue boards to capture attracted flies. Smaller traps have been sold to use in homes and small rooms, but few if any trap evaluations can be found in the literature. One trap, the DynaTrap Flylight DT-3009 (DTFL) has become quite common and a performance evaluation between it and an open-front commercial trap seemed warranted. Evaluations were conducted at the USDA-ARS-CMAVE laboratory in Gainesville, FL. The DTFL and the Gardner GT-200 open-front trap were evaluated individually and then in pairs. Traps were placed approximately 90 cm above the floor at the edge of a 2.4- × 0.76-m wide counter. Traps tested individually were centered on the long axis of the counter. For paired tests, traps were placed approximately 2.1 m apart. Fifty mixed-sex, 3- to 5-d-old house or stable flies were released and counts of captured flies were made after 1, 4, and 24 h. In individual tests, the DTFL and the GT-200 captured 38 and 76% of the house flies, respectively, and 3 and 18% of the stable flies, respectively, after 4 h. At 4 h in paired tests, the DTFL and the GT-200 captured 3 and 66% of the house flies, respectively, and 2 and 16% of the stable flies, respectively. Depending on the intended use, either trap was considered efficacious in capturing house flies when used alone. Differences in trap performance are discussed.

Comparison of Mosquito Abundance From Biogents Sentinel 2.0 Traps With and Without Rain Covers.

Biogents Sentinel (BGS) traps have rapidly become a standard for adult Aedes aegypti surveillance. Several investigators have found that trap collections can be damaged easily by heavy dew or rain entering the trap intake port. In addition, water entering the trap may temporarily stop the fan, thus reducing the collection potential of the trap. We evaluated the effectiveness of a rain cover designed to minimize damage to mosquito trap collections from BGS 2.0 traps in a residential backyard in Jacksonville, FL. Rain covers consisted of white fiberglass 51-cm2 sheets positioned 19, 29, and 39 cm above the air intake of the traps. One BGS trap did not have a rain cover and was used as a control standard for comparison. All traps were baited with the BG-Lure. Generally, traps with rain covers resulted in higher mosquito counts when compared with collections from uncovered traps. Overall mosquito abundance was greater from traps with the rain cover positioned at 29 cm, but this difference was not significantly different when compared with the other cover heights. Covers spaced 29 or 39 cm collected significantly more Culex quinquefasciatus compared with traps at 19 cm and no cover. Species diversity was greatest for BGS traps with the rain cover positioned at 29 cm followed by 39 cm, 19 cm, and no cover; however, differences in diversity among the traps, with or without covers, were not significant.

Comparative Efficiency of Biogents Gravid Aedes Trap, Cdc Autocidal Gravid Ovitrap, and CDC Gravid Trap in Northeastern Florida.

We conducted a study to compare the effectiveness of the Biogents Gravid Aedes Trap (BG-GAT) and Centers for Disease Control and Prevention (CDC) Autocidal Gravid Ovitrap (AGO) with that of the CDC Gravid Trap (CDC-GT) (as a standard) for their proficiency to collect mosquitoes in an urban residential neighborhood in northeastern Florida. Aedes aegypti , Ae. albopictus, and Culex quinquefasciatus were collected from each trap, with the latter species being predominant. Significantly more Cx. quinquefasciatus were collected from CDC-GT traps compared with the other 2 traps. Pairwise comparison of the efficiency of the CDC-GT revealed that this trap collected 6.7- to 21.5-fold more mosquitoes than the BG-GAT, depending on species. The BG-GAT collected overall more mosquitoes (3- to 6-fold) than the AGO, with the exception of Ae. aegypti, where both traps were nearly equal in effectiveness.

Comparison of Adult Mosquito Abundance From Biogents-2 Sentinel and Biogents Gravid Aedes Traps In Northeastern Florida.

We compared the efficacy of the Biogents Gravid Aedes Trap (BG-GAT) and Biogents-2 Sentinel (BG2S) trap to assess differences in adult mosquito collection rates between these 2 mosquito surveillance methods in northeastern Florida. Species diversity of trap collections was significantly greater for BG2S than for BG-GAT, with 14 mosquito species collected from the former trap and 4 species from the latter. Aedes aegypti and Culex quinquefasciatus were the 2 predominant species collected in both traps. Overall, BG2S traps collected significantly more mosquitoes (in some instances nearly 5 times) than the BG-GAT, regardless of species. There was no significant difference between the 2 traps with respect to gravid status when total species and number of mosquitoes collected were compared. However, at the species level, 8% of Ae. aegypti were gravid from the BG-GAT collections compared with 1% from the BG2S. The number of gravid Cx. quinquefasciatus was also considerably greater (59%) for the BG-GATs than for BG2S traps (2%), but these relationships were not statistically significant due to high variability in collections between traps.

Operational Evaluation Of Vectomax® WSP (Bacillus thuringiensis Subsp. israelensis+Bacillus sphaericus) Against Larval Culex pipiens in Septic Tanks (1).

The residual effectiveness of VectoMax® WSP (a water-soluble pouch formulation containing a combination of Bacillus thuringiensis subsp. israelensis strain AM65-52 and B. sphaericus strain ABTS 1743) when applied to septic tanks against 3rd- and 4th-stage larvae of Culex pipiens L. was evaluated in this study. This formulation was evaluated at operational application rates of 1 pouch (10 g) and 2 pouches (20 g) per septic tank. Both application rates resulted in >96% control of larvae for 24 days. Operationally, VectoMax WSP has proven to be a useful tool for the nonchemical control of Culex species in septic tank environments.

Larvicidal activity of selected plant hydrodistillate extracts against the house mosquito, Culex pipiens, a West Nile virus vector.

The larvicidal activity of hydrodistillate extracts from Chrysanthemum coronarium L., Hypericum scabrum L., Pistacia terebinthus L. subsp. palaestina (Boiss.) Engler, and Vitex agnus castus L. was investigated against the West Nile vector, Culex pipiens L. (Diptera: Culicidae). Yield and identification of the major essential oils from each distillation was determined by GC-MS analyses. The major essential oil component for each plant species was as follows: α-pinene for P. terebinthus palaestina, and H. scabrum (45.3% and 42.3%, respectively), trans-ß-caryophyllene for V. agnus castus (22.1%), and borneol for C. coronarium (20.9%). A series of distillate concentrations from these plants (that ranged from 1 ppm to 500 ppm, depending on plant species) were assessed against late third to early fourth C. pipiens larvae at 1, 6, and 24 h posttreatment. In general, larval mortality to water treated with a distillate increased as concentration and exposure time increased. H. scabrum and P. terebinthus palaestina were most effective against the mosquito larvae and both produced 100% mortality at 250 ppm at 24-h continuous exposure compared with the other plant species. Larval toxicity of the distillates at 24 h (LC(50) from most toxic to less toxic) was as follows: P. terebinthus palaestina (59.2 ppm) > H. scabrum (82.2 ppm) > V. agnus castus (83.3 ppm) > C. coronarium (311.2 ppm). But when LC(90) values were compared, relative toxicity ranking changed as follows: H. scabrum (185.9 ppm) > V. agnus castus (220.7 ppm) > P. terebinthus palaestina (260.7 ppm) > C. coronarium (496.3 ppm). Extracts of native Turkish plants continue to provide a wealth of potential sources for biologically active agents that may be applied against arthropod pests of man and animals.

Comparative efficacy of spinosad with conventional acaricides against hard and soft tick populations from Antalya, Turkey.

The acaricidal efficacy of ceramic tiles treated at field application rates with either spinosad (Mozkill 120 SC, 0.01 g ai/m(2)), deltamethrin (Impotek Deltamethrin EW, 0.01 g ai/m(2)), permethrin+esbiothrin (Chrysamed, 0.1 g ai/m(2)), chlorpyrifos-methyl (Chlortoks EC 50, 0.2 g ai/m(2)) or a mixture of alpha-cypermethrin/tetramethrin/piperonyl butoxide (Ecorex Alfa SE, 0.01 g ai/m(2)), against larval Rhipicephalus turanicus and Argas persicus ticks was determined in laboratory bioassays. All ticks were initially exposed to treated tiles for 15 min then removed to non-treated containers and mortality evaluated for 15 min, 1 h, 6 h, and 24 h postexposure. Generally, A. persicus proved to be the most susceptible of the two species to all treatments. The alpha-cypermethrin/tetramethrin/piperonyl butoxide mixture was the quickest acting acaricide against larval A. persicus where 100% mortality was observed 15 min postexposure. For the rest of the treatments complete mortality was obtained at 1 h except for permethrin/esbiothrin which occurred at 6 h postexposure. Complete mortality of larval R. turanicus occurred to deltamethrin and spinosad at 1 h postexposure with all acaricides providing 100% control at 6 h except permethrin/esbiothrin which only achieved 92% control through the end of the study (i.e. 24 h). Our results showed that spinosad would be a useful addition in a tick control program as an alternative for pyrethroids and organic phosphorus acaricides against both tick species.

Acaricidal effects of the essential oil of Origanum minutiflorum (Lamiaceae) against Rhipicephalus turanicus (Acari: Ixodidae).

The acaricidal effects of the volatile essential oil Origanum minutiflorum O. Schwarz & P.H. Davis (Lamiaceae) against adult Rhipicephalus turanicus was evaluated at a variety of concentrations and exposure times. Generally tick mortality increased with concentration and exposure. Ticks exposed to vapors from cotton wicks containing at least 10mul/L resulted in complete (100%) mortality at 120min. The major constituent of essential oil obtained from the plant material of O. minutiflorum was carvacrol.

Evaluation of the naturally-derived insecticide spinosad against Culex pipiens L. (Diptera: Culicidae) larvae in septic tank water in Antalya, Turkey.

The naturally-derived insecticide spinosad (Conserve SC) was evaluated against larval Culex pipiens L. (Diptera: Culicidae) under laboratory and field conditions in Antalya, Turkey. Laboratory bioassays showed that the 24 h LC50 and LC90 against late 3rd and early 4th instars were estimated at 0.027 and 0.111 parts per million, respectively, while adult emergence was eliminated at concentrations above 0.06 ppm. Larval mortality from septic tanks that were treated with spinosad at rates of 25, 50, 100, and 200 g ai/ha ranged between 22 to 78% 1 day after application. At 7 days post-treatment, larval mortality ranged from 2 to 50% and at 14 days mortality was <10% for all treatments. Larval bioassays of the water from those septic tanks treated at 100 and 200 g ai/ha resulted in an elimination of Cx. pipiens larvae 7 days after treatment. After this time, larval reduction declined to 79 and 83%, respectively, 14 days after treatment. Larval reduction in septic tanks treated at the two lowest rates (i.e. 25 and 50 g ai/ha) ranged from 14 to 74% during the 14-day study. These results indicated that spinosad can be considered an effective larvicide for treatment of septic tanks against Cx. pipiens.