Evaluation of Pyrethrin and Permethrin Ground Ultra-Low Volume Applications for Adult Culex Control in Rural and Urban Environments of the Coachella Valley of California

Abstract

Six experimental ground ultra-low volume (ULV) applications of Pyrenone 25-5 (0.0025 lb/acre) and Aqua-Reslin (0.007 lb/acre) were made by truck-mounted Pro-Mist or London Fog equipment over 1-mi2 study areas in rural and residential environments of the Coachella Valley, Riverside County, California. Efficacy of replicate applications was evaluated by measuring mortality among caged sentinel mosquitoes, by evaluating changes in host-seeking abundance at replicated dry ice-baited traps positioned along intersecting east-west and north-south transects, and by differential recapture patterns of marked females released near traps in the sprayed central core and unsprayed control areas. Sentinel mortality agreed well with estimates of droplet density measured by "slide spinners" and was affected by 1) distance of cages from the truck route; 2) landscape features, such as tree lines that created wind shadows; 3) irregular landscape that disrupted the particle cloud; 4) low wind speed that failed to carry the droplet cloud through the environment; and 5) failure of the droplets to penetrate dead airspace within stands of vegetation. Despite variable sentinel mortality, Culex tarsalis relative abundance in rural landscapes within and around our study areas always declined after ULV applications. Concurrent decreases in abundance at traps within sprayed and adjoining unsprayed areas confounded our estimates of percentage of control using Mulla's formula, which compares abundance in sprayed and unsprayed areas pre- and postspray. ULV applications significantly affected recapture patterns, in that recapture rates within the spray zone usually were significantly less than in the unsprayed zone. Collectively, our data indicated that ground ULV applications measurably reduced Cx. tarsalis abundance in rural areas of the Coachella Valley but that further evaluations may be necessary to validate efficacy on Culex quinquefasciatus populations in residential communities.

Effects of exposure to pyrethroid cyfluthrin on serotonin and dopamine levels in brain regions of male rats

“…Pyrethroids are more stable in light and air than natural pyrethrins. Today, they are one of the most widely used domestic and agricultural pesticides (Heudorf and Angerer, 2001;Lothrop et al, 2007), they are used to control pests in residential and agricultural settings, to treat head lice and scabies in humans and fleas in pets, for public health vector control, and for disinfection of commercial aircrafts (Anadón et al, 2009(Anadón et al, , 2013aWei et al, 2012;USEPA, 2013). Pyrethroid insecticides account for more than 30% of insecticides used worldwide (Barr et al, 2010).…”

Evaluation of ULV and Thermal Fog Mosquito Control Applications in Temperate and Desert Environments

“…Multiple factors including environmental conditions have a significant impact upon the efficacy of aerosols used in adult mosquito control operations; for instance, hotarid climates are likely to be particularly problematic because of impacts such as rapid evaporation. No studies have been identified that look at the performance of thermal fog in hot, dry conditions; however, ground and aerial ULV aerosol pesticide delivery in hot dry conditions has been carried out with mixed outcomes against desert locusts (Holland and Jepson 1996) and mosquitoes (Lothrop et al 2007a, Lothrop et al 2008, in part because of population dynamics or wind conditions at the time of delivery. No studies have been identified that investigate differences in success of ULV or thermal fog (or ULV and thermal fog side by side) applications in hot, dry compared to warm, moist conditions, regardless of wind conditions.…”

The attribution of urban and suburban children's exposure to synthetic pyrethroid insecticides: a longitudinal assessment

“…Pyrethroid insecticides, a group of synthetic insecticides, are widely used in agriculture and public health programs worldwide (Heudorf and Angerer, 2001;Lothrop et al, 2007). Their availability for consumer use in the household has increased since the early 2000s (US Environmental Protection Agency, 2005) when restriction on use of organophosphorus pesticides (OPs) in residential environments in the United States was imposed (US Environmental Protection Agency, 1998).…”