Fatally impaired glucose digestion by propylene glycol in Aedes aegypti (Diptera: Culicidae) and co-formulation with terpenoids for enhancing attractive toxic sugar baits.

Propylene glycol (PG) demonstrates greater efficacy than other sugar polyols. However, the attributes it confers for toxicity and possible co-formulation with other ingredients are unknown. To evaluate this, α-glucosidase and glucose oxidase reactions were performed in Aedes aegypti (L.) (Diptera: Culicidae) to categorize if PG behaves similarly to prior studied sugar alcohols. A combination of no-choice and choice assays was used to determine effective ratios of PG and sucrose, competitiveness against a control of 10% sucrose, and whether mosquitoes recovered from PG consumption. The final trials included ß-cyclodextrin encapsulated cinnamon leaf oil, clove stem oil, patchouli oil, garlic oil, cedarwood oil, and papaya seed oil formulated with 5% sucrose + 5% PG. PG functioned as a linear competitive inhibitor of α-glucosidase. The efficacy of PG was synergized by co-ingestion with equivalent ratios of sucrose. Unlike the high diuretic response to other sugar alcohols, PG resulted in diminished excretion regardless of being co-formulated with sucrose or terpenoids. PG is not especially competitive against unadulterated sugar meals but is likewise not clearly repellent. Although mosquitoes did not recover from ingestion of the glycol meals, there was no indication that mortality would continue to accumulate once the treatments were removed. Of the terpenoids tested, cinnamon and patchouli caused ~50% or less mortality; garlic, cedarwood, and clove caused 80-90% mortality; and papaya seed caused 100% mortality, exceeding all other test groups and the formulation blank. PG is a useful supporting ingredient in attractive toxic sugar bait formulations with flexibility in formulation.

The Role of Temperature, Wind Speed, and Precipitation on the Abundance of Culex Species and West Nile Virus Infection Rate in Rural West-Central Illinois.

While most research on West Nile virus (WNV) and its main vector, the Culex mosquito, has been conducted in laboratory or urban settings, studies with field-caught mosquitoes in rural areas, such as west-central Illinois, are lacking. The objective of this research was to investigate key abiotic factors using macroclimate data, including temperature, precipitation, and wind speed, to determine their influence on field-caught mosquito abundance in 4 rural counties in Illinois from 2014 to 2016. Additionally, the relationship between minimum infection rate (MIR) and thermal time was examined. Using gravid traps at 15 sites, Culex mosquitoes were collected twice a week. A total of 5,255 adult female Culex mosquitoes (Cx. pipiens, Cx. quinquefasciatus, and Cx. restuans) were collected in 2014; 9,138 in 2015; and 5,702 in 2016. Regression models were developed based on outcomes of relationships between field-caught mosquitoes and abiotic factors. Precipitation and thermal time had the most significant relationship with mosquito abundance (r2 = 0.993 and r2 = 0.993, respectively), while wind speed was less (r2 = 0.714). The greatest number of Culex and the highest annual MIR were observed in 2015, which was also the driest of the 3 sampling seasons. Mosquito abundance was observed to increase with warmer degree days and MIR was found to increase with abundance in mosquitoes. These models can be used for other mosquito surveillance and monitoring studies in various climate types and environments.

Distribution of Invasive Aedes Mosquitoes in West-Central Illinois, 2014-18: Record Updates for Aedes japonicus and Ae. albopictus.

A comprehensive surveillance of Aedes mosquitoes in west-central Illinois has not been conducted in recent years, resulting in incomplete distribution records for several Illinois counties. As of 2014, out of 102 Illinois counties, active populations of Ae. japonicus had been confirmed in 15 counties, and Ae. albopictus confirmed in 34 counties. The Miller laboratory at Western Illinois University (WIU) began the WIU Vector Biology Initiative (WIU-VBI) in 2014 to address the lack of mosquito surveillance in west-central Illinois. Through this effort, the presence of Ae. japonicus was confirmed for the 1st time in Fulton, Hancock, and Schuyler counties, IL, from 2014 to 2018. Actively breeding populations were confirmed in Cass, Fulton, McDonough, and Schuyler counties, IL. Additionally, Ae. albopictus was observed for the 1st time in Cass, Fulton, Hancock, McDonough, and Schuyler counties, IL, in 2016 and 2017, with active breeding populations in Cass and McDonough counties, IL.

A New Record of Uranotaenia sapphirina and Aedes japonicus in Lee and Ogle Counties, Illinois.

Mosquito surveillance was conducted in Nachusa Grasslands Preserve located in north central Illinois in May through October during 2018 and 2019. In the Lee and Ogle counties, Illinois, boundaries of the preserve, 3 Uranotaenia sapphirina and 3 Aedes japonicus were collected and documented over the 2 field seasons in wetland and stream habitats. While Ur. sapphirina has been reported in nearby states, this is the first record in Lee County and on the preserve. Aedes japonicus has previously been recorded in Lee County; however, this is the first observance of this species within Ogle County and on the preserve.