Measurement of the effect of microsporidian pathogens on mosquito larval mortality under artificial field conditions.
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to D A Dame.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Simultaneous ground and aerial adulticide applications were evaluated against riceland mosquitoes in Stuttgart, AR, during July 1985. Naled was aerially applied at 52.6 ml/ha over 10.4 km2 surrounding the city. Ground ULV applications of a mixture of malathion, HAN and resmethrin/PBO (1:1:0.0625) were applied within the city at a rate of 221.8 ml/min at 24 kph. Adult populations of Anopheles quadrimaculatus and Psorophora columbiae were reduced at 24 hr but resurgence of Ps. columbiae was evident at 48 hr posttreatment. Posttreatment data indicated that movement of both mosquitoes occurred along the path of prevailing wind.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
In a survey of containers infested with Aedes aegypti (L.) conducted during September and October 1979 in a substandard residential area of New Orleans, LA, infestation indices were as follows: House--35, Breteau (foci)--85, Receptacle--69, Block--100, and Larval Density--169. A mean of 48.5 water-holding containers were found per block. More than 50% of these receptacles were narrow-mouthed containers, e.g., drink bottles, that held an average of less than 0.03 mosquito immatures each. After exclusion of data on the unproductive narrow-mouthed type, the average container held 7.8 liters of water, 105 1st and 2nd instars, 69 3rd an 4th instars, and 12 pupae. With assumed constant adult survival rates of 0.85-0.90 per day, the number of females per block on any particular day was estimated from pupal production data at 362-558, and the standing crop of females 12 days and older and therefore old enough to transmit dengue fever if they are vector competent was estimated at 51-158 per block.
Explore the source record for details and available documents.
Technology was developed for mass rearing males of the genetically altered MACHO strain of Anopheles albimanus Wiedemann, which allowed for elimination of females by treating the eggs with propoxur (o-isopropoxyphenyl methylcarbamate). This made it possible to eliminate virtually all the females (potential malaria vectors) being released in the field, and also reduced the space previously devoted to larval rearing by 50%, since the females were eliminated in the egg stage. Also, the difficulties involved in separating the sexes with previous techniques were eliminated. Because there is some genetic recombination, about 0.2% of the MACHO males become susceptible and an equal number of females become resistant each generation. Thus after 6-12 months, the strain is purged to remove these contaminants. With this system an average of more than 1 million pupae per day was produced during 3 weeks of a 5-week period, and an average of 968.2 thousand per day during the entire period. The pupae produced were 99.9% males with an average adult emergence of 90%.
During a 3-year program that required daily releases of large numbers of sterile male Anopheles albimanus Wiedemann mosquitoes in a coastal area of El Salvador, we were able to compare methods of transport and release of adults and pupae. The disadvantages of the laboratory handling and packaging of adults were largely overcome when improved methods were devised for release of pupae. Such releases saved time and laboratory space and overcame several logistical problems arising from evening releases of the adults. We finally achieved 91.3% emergence with the pupal release methods.
Technology was developed for sterilizing and packaging as many as 1 million male Anopheles albimanus Wiedemann per day for field release. The average sterility produced in the males during a 1.5-year period was 98.9%. Mortality due to transport of the males in specially developed cages averaged 4.5% for 72-hour-old adults and 2.5% for 24-hour-old adults. The average mortality due to transport and field exposure of pupae was 1.2 to 9.8%, depending on the technique used.
Recent field experiments demonstrated the possibility of using the sterile male method for the control of Anopheles albimanus Wiedemann, the most important vector of human malaria in Central America. Until now there was no practical method for excluding females from the releases of sterile males. A genetic method was developed for the preferential elimination of females during any of the four life stages. This genetic sexing system utilizes propoxur (o-isopropoxyphenyl methyl-carbamate) susceptibility as a recessive conditional lethal a T(Y:2R) translocation, and an In(2R)inversion. The propoxur resistance allele (dominant) was linked to the Y chromosome via a radiation-induced translocation, and genetic recombination was suppressed by inversions. In one of the strains produced, 99.7 percent of the females are eliminated when treated with propoxur, without male loss.
Explore the source record for details and available documents.
Maintenance of unknown-age tsetse puparia at 4 degrees C for six days substantially reduced emergence; normal emergence occurred when puparia were held at temperatures of 12 degrees, 14 degrees, or 16 degrees C for two, three or four weeks, respectively. In-storage eclosion of adults was either suppressed completely at the temperatures used or was slight. Weight, puparial duration, and density of puparia were examined in an attempt to detect sexual differences in puparia. There appeared to be no usable correlation between pupal weight and sex, but the difference between the puparial duration of each sex offers a mechanism for retaining 81% of the females produced and releasing 84% of the males. The flotation of unknown-or known-age puparia in methanol-water solutions of varying specific gravities demonstrated some diffences in the density of male and female puparia. However, these differences were not great or consistent enough to provide an efficient system of separating puparia by age or sex.
Explore the source record for details and available documents.