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Biomedical subjects

L R Boobar

Publications and source records attributed to L R Boobar.

At least 19 recordsLinked to original sources

Quantitative evaluation of sampling methods for Ixodes dammini and Amblyomma americanum (Acari: Ixodidae).

Three tick-sampling methods (dry ice-baited tick traps, cloth drags, and ambulatory human host) were evaluated to determine which technique yielded the greatest capture of host-seeking stages of Ixodes dammini Spielman, Clifford, Piesman & Corwin and Amblyomma americanum (L.). The most reliable method, catching more stages and significantly more numbers of I. dammini and A. americanum; was dry ice-baited tick traps. There were no significant differences between the drag and human-host methods for any stage of ticks (I. dammini and A. americanum) collected. The numbers of ticks caught during the study were 5,052 by dry ice-baited tick traps, 199 by cloth drags, and 89 by ambulatory human host.

Animals↗

Field evaluation of two formulations of cyfluthrin for control of Ixodes dammini and Amblyomma americanum (Acari: Ixodidae).

Liquid or granular cyfluthrin was applied in the spring and fall to different test plots at a rate of 0.41 (AI) kg/ha to control Ixodes dammini Spielman, Clifford, Piesman & Corwin and Amblyomma americanum (L.). Spring application of liquid cyfluthrin showed the most significant decreases of both species. I. dammini nymphs were reduced 97% at 10 d, 100% at 2 mo, and 100% at 1 yr; and A. americanum adults and nymphs were reduced 91-93% at 10 d and 100% at 2 mo posttreatment. Granular cyfluthrin applied in the spring gave 97 and 87% control of nymphal I. dammini 10 d and 2 mo posttreatment, respectively.

Animals↗

A fabric body light trap for sampling mosquitoes.

A Fabric Body light trap has been developed that has unique features of a cloth body, folding rainshield and a modified folding net. These features allow the light trap to be reduced in size and weight for transportation and storage while retaining the same operational characteristics as the Solid State Army Miniature (SSAM) light trap.

Aedes↗

Botanical derivatives in mosquito control: a review.

A review on the reported uses of chemicals derived from botanical sources is presented, along with the part of the plant used for extraction, the mosquito species studied and the bioactivity observed for 344 plant species. Examples of phytochemicals evaluated against mosquitoes as general toxicants, growth and reproduction inhibitors, repellents and ovipositional deterrents are given. The effects of mosquito species and life stage specificity, solvents used for extraction, phototoxic activity and the geographical source from where the plant compounds are derived are discussed.

Aedes↗

Field evaluation of four biorational larvicide formulations against Anopheles albimanus in Honduras.

Four biorational larvicide formulations: Teknar (B.t.i.), Arosurf MSF (Monomolecular Surface Film), Arosurf MSF combined with Teknar, and SAN-809-I ([s]-methoprene combined with B.t.i.), were evaluated against naturally occurring populations of the malaria vector mosquito Anopheles albimanus Wiedemann in Honduras. All formulations reduced the mean number of larvae per sample area to 0 within 48 h after treatment, and gave significant (P less than 0.05) control when compared with similar untreated areas for at least 10 days after treatment. It is concluded that each of these four formulations can be used effectively to control the larvae of An. albimanus in Honduras.

Animals↗

Integrated use of planaria (Dugesia dorotocephala) and Bacillus thuringiensis var. israelensis against Aedes taeniorhynchus: a laboratory bioassay.

The effectiveness of integrating Bacillus thuringiensis var. israelensis (B.t.i.) and the predatory planaria, Dugesia dorotocephala against Aedes taeniorhynchus was determined under controlled laboratory conditions. There was no significant effect (P greater than 0.05) of B.t.i. on D. dorotocephala either by direct association or through ingestion of B.t.i. dosed larvae. Planaria, alone, and B.t.i. combined with planaria, both provided significant (P less than 0.05) reduction of Ae. taeniorhynchus populations through the 12-week evaluation.

Aedes↗

A new housing for the Battery-operated Aerosol Droplet Sampler Model 312.

Rotating impactors are more efficient aerosol droplet collectors than stationary impactors. Breakage of the phenolic plastic housing on a commercial rotating impactor during shipment has reduced this laboratory's ability to collect droplet data. Directions for replacing that housing with an aluminum BUD box are presented.

Electric Power Supplies↗

Comparison of ground and aerial ultra-low volume applications of malathion against Aedes aegypti in Santo Domingo, Dominican Republic.

Efficacy of ground and aerial ultra-low volume (ULV) applications of 91% malathion at 438 ml/ha against Aedes aegypti in the Dominican Republic was evaluated using indoor collections, oviposition trapping and adult sentinel mortality rates. Ground compared to aerial ULV applications in this study were found to have a greater effect on Ae. aegypti when measured by the described sampling techniques. Neither application method provided the level of Ae. aegypti suppression believed necessary for control in the event of a dengue virus epidemic.

Aedes↗

Culicidae (Diptera) mortality resulting from insecticide aerosols compared with mortality from droplets on sentinel cages.

The mortality of female Aedes aegypti exposed to an ultralow-volume (ULV) aerosol for 15 min and then transferred to clean cages was compared to the mortality of females exposed to the contaminated sentinel exposure cages. ULV aerosol sprays of fenitrothion (50% AI) were dispersed at 180 and 205 ml/min, and ULV aerosol sprays of bendiocarb (18.87% AI) were dispersed at 90 and 120 ml/min in an open field. At 24 h after exposure, the mean percentage of mortality of Ae. aegypti in cages previously exposed to insecticides was 87% at 46 m and 71.8% at 91 m downwind of aerosol generation for the four flow rates. The mean percentage of mortality of Ae. aegypti exposed to the aerosol and then transferred to clean cages was 74.5% at 46 m and 68% at 91 m. Insecticide droplets deposited on exposed cages caused significant mortality to Ae. aegypti. Data show that sentinel mosquitoes used in insecticide bioassays should be transferred into clean holding containers as soon as possible after exposure to prevent biasing of results from insect contact with insecticide deposited on cage walls and screens.

Aerosols↗

Reduction of the Amblyomma americanum (Acari: Ixodidae) population at Fort A.P. Hill, Virginia, by aerial application of diazinon granules: correlation of percentage control with received dose.

Habitat (280 ha) of lone star tick, Amblyomma americanum (L.), was aerially treated with 14% diazinon granules. Concentration of acaricide reaching the forest floor ranged from 0.02 to 1.25 kg (AI)/ha. Greater than 85% control was achieved at study plots receiving the highest dose. A positive correlation was shown between dose received at the forest floor and percentage of control of adults (r = 0.91) and nymphs (r = 0.86).

Animals↗

Aerosol penetration relative to sentinel cage configuration and orientation.

Aerosol movement into 4 different sentinel cage configurations at 0 degrees, 30 degrees and 60 degrees orientation relative to the aerosol flow in a wind tunnel was studied using a quartz crystal microbalance cascade impactor. The data suggest that a cylinder, screened on all sides, with the longitudinal axis perpendicular to the ground would provide a consistent cage profile to the wind regardless of wind direction changes and thereby reduce aerosol environment variability among cages.

Aerosols↗

Effects of screen materials on droplet size frequency distribution of aerosols entering sentinel mosquito exposure tubes.

Aerosol filtration effects of three types of mesh screen used for mosquito cages were evaluated with aerosolized water, mineral oil and chlorpyrifos. The screen materials were two nylon tulles (3 x 4 and 8 x 11 repeats per cm2) and corrosion-resistant steel (7 x 7 repeats per cm2). Open areas of these three mesh materials were, respectively, 94%, 79% and 88%. Aerosol droplet size frequency distributions were altered when passed through test screens of these materials fitted to standard tubes from World Health Organization test-kits for exposure of adult mosquitoes. The alterations included reductions in total droplets and volume median diameter (VmD). Nylon screen with fewer repeats of the mesh altered droplet VmD and frequency distribution the least, allowing the greatest number of droplets to enter sentinel mosquito cages for bioassays of mortality-rates. The greater filtration effect of screens with less open area, giving rise to selective deposition of particular droplet sizes on the screen material, could result in anomalous exposures of test mosquitoes to contact with insecticide filtrate on the screen substrate. This might help to explain the poor correlation often observed between insecticide aerosol impact on wild target mosquito populations as compared with sentinel caged mosquitoes. In addition to other standard test procedures, the need for standardization of materials used for construction of sentinel cages employed for aerosol bioassays is emphasized.

Aerosols↗

A new type of collapsible insect-surveillance light trap for sampling Diptera.

The newly designed Army Collapsible Insect Surveillance trap for nocturnal collection of flying Diptera that are attracted by light is described. A polyvinyl chloride construction increases durability, while the capability to collapse from a height of 92.1 cm to 24.1 cm facilitates transportation and storage.

Animals↗