RESUMEN
Deposition of malathion and permethrin onto grass surfaces, after ultra-low volume (ULV) application, was studied in a suburban neighborhood in Saginaw County, Michigan. Commercial concentrates of malathion (Cythion ULV) and permethrin (Biomist 4 + 12) were sprayed using a truck-mounted ULV aerosol generator. Sod-grass blocks (0.18 m2) were placed in the frontyard and backyard of homes in the neighborhood at 4 distances to 91.4 m from the road where applications were made. Grass samples were taken from the sod blocks before application and at 15 min, 12 h, 24 h, and 36 h after application. Samples were extracted with solvent, and extractions were subjected to gas-liquid chromatography for detection of malathion and permethrin. Ranges of detection for malathion were 0.0-16.6 mg/0.18 m2 and for permethrin were 0.0-25.9 mg/0.18 m2. Most detections were from samples taken nearest the road at 15 min after application. Detections declined as a logarithmic function of time after application and as an exponential function of distance from the road.
Asunto(s)
Malatión , Control de Mosquitos , Residuos de Plaguicidas , Piretrinas , Michigan , Permetrina , PoaceaeRESUMEN
Liquid Bacillus thuringiensis H-14 (Acrobe) was applied from fixed-wing aircraft at a rate of 4.68 liters of water-insecticide mixture (1.17 liter concentrate) per hectare to woodland pools in Michigan. A post-treatment larval survey indicated an 88.5% reduction in Aedes species larvae. A volume median diameter of 208 microns was determined.
Asunto(s)
Aedes , Bacillus thuringiensis , Control Biológico de Vectores/métodos , Animales , Ecología , Larva , Michigan , Tamaño de la PartículaRESUMEN
A sustained-release, briquet formulation of methoprene (Altosid XR), applied at a rate of one briquet per catch basin in Saginaw, Michigan, provided ca. 70% reduction in emergence of Culex pipiens and Cx. restuans adults, compared with nontreated catch basins, during a period of 15 wk in the summer of 1990. In a parallel study using one briquet per 10.5 liter bucket, there was 99% reduction in adult emergence of these species for a period of 12 weeks. The difference between catch basins and buckets may be attributable to water movement through the catch basins with each rainfall, causing a dilution of methoprene through time. However, both studies indicated that the briquets released methoprene for 12-15 wk, suggesting that this formulation may offer season-long control of Culex mosquitoes from urban catch basins in Michigan, with a single treatment of insecticide.
Asunto(s)
Culex , Metopreno , Control de Mosquitos/métodos , Animales , Preparaciones de Acción Retardada , Ecología , Michigan , Población UrbanaRESUMEN
Liquid B.t.i. (Vectobac 12AS), when mixed with water at a 1:3 ratio and applied by helicopter at a rate of 1.17 liters B.t.i. (4.68 liters mix) per ha, was 99% effective in a small (mass median diameter on dye cards: 178 microns) droplet size but ineffective (65%) in a large (553 microns) droplet against spring Aedes larvae in snowmelt pools. There were about 6 times as many smaller droplets as larger ones impacting the treated pools, which probably explained the difference in effectiveness for the 2 treatment regimes. Results indicate that liquid formulations of B.t.i. could be aerially applied for spring Aedes control at a considerable cost savings and efficiency over aerially applied, granular formulations.