ABSTRACT
Previous reports from the literature have indicated the northernmost range of extension of Ixodes minor Neumann to be southern Georgia with the greatest number of collections having been made in the coastal regions of that state. An unpublished record in the U.S. National Tick Collection indicated that I. minor had been collected as far north as South Island, Georgetown County, S.C., as early as 1933. I. minor was collected on three separate occasions in Charleston County, S.C., between October 1990 and February 1991, thus verifying the northern extension of this tick's range and the probable existence of a stable population on the coast of South Carolina. The roof rat (Rattus rattus) is reported for the first time serving as a host for I. minor.
Subject(s)
Muridae/parasitology , Rodent Diseases/parasitology , Tick Infestations/veterinary , Ticks/isolation & purification , Animals , Female , Rats , South Carolina , Tick Infestations/parasitologyABSTRACT
The insecticide susceptibility of Aedes aegypti adults and larvae from Santo Domingo, Dominican Republic, was investigated using World Health Organization standard procedures. A field strain was more resistant to insecticides than a colony strain that originated from the same place. Larvae produced from ovitrap-collected eggs were resistant to temephos (78.2% mortality on exposure to 0.025 mg/liter). Mortality rates after exposure of adults to discriminating concentrations showed that wild populations were resistant to DDT, malathion, propoxur, permethrin and deltamethrin. The problem of resistance was considered serious enough to warrant consideration of control measures other than the use of chemicals.
Subject(s)
Aedes , Insecticides , Animals , DDT , Dominican Republic , Insecticide Resistance , Larva , Malathion , Nitriles , Permethrin , Propoxur , Pyrethrins , Species Specificity , TemefosABSTRACT
Susceptibility tests were conducted using the World Health Organization diagnostic test procedure on strains of Aedes taeniorhynchus, Aedes sollicitans, Aedes vexans, and Culex nigripalpus collected from several localities in Charleston and Georgetown counties of South Carolina. Aedes taeniorhynchus was resistant to malathion (mortality 1.0-54.4%) but not to propoxur, permethrin, or fenitrothion. There also were indications that Ae. sollicitans and Cx. nigripalpus were resistant to malathion, but to a lesser extent than Ae. taeniorhynchus (mortalities: 72.1-81.0%, and 46.2%, respectively). Aedes vexans was susceptible to malathion (mortality 98.6%). In field tests using ULV application of malathion and field-collected Ae. taeniorhynchus, and susceptible Ae. aegypti and Ae. taeniorhynchus, a noticeably lower mortality also was obtained in the wild mosquitoes.
Subject(s)
Culicidae , Malathion , Mosquito Control/methods , Aedes , Animals , Culex , Female , Fenitrothion , Insecticide Resistance , Insecticides , Larva , Permethrin , Propoxur , Pyrethrins , South Carolina , Species SpecificityABSTRACT
Four handheld aerosol-mist generators and 1 thermal fog generator were evaluated initially for their ability to deliver low flow rates (< or = 5 ml/min) of resmethrin insecticide. Two generators, the London Fog Eliminator and Clarke Pl, were then selected from that group to conduct a treatment of a block of 16 residences (4 x 4 grid) vs. direct treatment of individual residences to determine the most efficacious method of treating a group of small dwellings or a village. Data are presented on droplet density, volume median diameter, and mortality of caged mosquitoes treated with the P1 and Eliminator in residences treated as a group; and mortality for caged Aedes aegypti L. in residences treated individually with the P1 at various flow control settings and spray-on times.
Subject(s)
Insecticides/administration & dosage , Mosquito Control/instrumentation , Pyrethrins/administration & dosage , Aedes , Aerosols , Animals , Female , HousingABSTRACT
In an effort to develop a more effective measure for use in emergency control of the dengue vector Aedes aegypti. applications of a combination of a larvicide (Bacillus thuringiensis israelensis [B.t.i.]) and an adulticide (permethrin) were made using a truck-mounted forced-air generator (Scorpion 20) and evaluated in the Dominican Republic. This method has the potential to simultaneously control adults and larvae. In bioassay cages placed in household water containers at the time of application, larval mortalities were 95.1 and 100% for 2 application rates of permethrin mixed with B.t.i. Adult mortalities were not as impressive, probably because of resistance to permethrin. Higher adult mortality in caged specimens (78.5%) and a substantial reduction in the natural population (68.4%) of Ae. aegypti were obtained following a 2.1-g AI/ha application of deltamethrin alone.
Subject(s)
Aedes , Bacillus thuringiensis , Insecticides , Mosquito Control/methods , Pyrethrins , Animals , Dominican Republic , Emergencies , Entomology/methods , Evaluation Studies as Topic , Larva , Mosquito Control/instrumentation , Permethrin , Pest Control, Biological/methodsABSTRACT
Baseline field studies were conducted from April 1987 to July 1988 on Aedes aegypti in Santo Domingo, an endemic area for dengue fever. Premise, container and Breteau indices were measured in one treated area and 2 nearby control areas. These indices averaged 69.6, 46.3 and 142.1, respectively. The principal larval habitats of Ae. aegypti were 208-liter (55-gal) concrete-lined drums. The estimated daily adult production was approximately 60 per house. Adult mosquito populations were monitored using oviposition traps and by sweep net collections. There was no correlation between adult abundance and the larval indices. Monitoring the natural adult densities was more efficient for evaluating the impact of ULV malathion application than the use of standard bioassay procedures.