And that’s a wrap: Mosquito Control Program 2020

GDG provided my office with a final mosquito control program report that examines the data collected throughout the 2020 season, and how successful treatments were.  

The information I am providing to you here is based on GDG’s final report and information. 

The goal of the program is to reduce the mosquito population by 80%. This means that there will still be mosquitoes in our community, however significantly less. The mosquito population, size and species has been shown to be influenced by weather conditions such a rainfall and temperature 

Through April and May this year, the snow melt caused areas to be saturated with water which triggered favourable development sites for spring mosquito larvaeDuring GDGs field monitoring iwas discovered there was the presence of spring speciesJune saw relatively normal precipitation, as there was one day with significant rainfall early in the month, while the weeks leading up and following were rather dryAugust saw many moderate rain events throughout the month, often continuing for several days. 

With a total of 442.4 mm of precipitation that fell in Ottawa from April to September and with GDGs growing knowledge of the area, they were able to respond quickly and effectively to the rain events 

Large bodies of water and sites with cold-water pools in Kanata had entered the early stages of larvae developmentIt took approximately 20 to 30 days for the spring species mosquito larvae to develop from the 1st instar stage to pupae. There are 4 stages of mosquito larvae1st instar, 2nd, 3rd and 4th. The pupae stage is when the adult structures are formed while the larvae structures are broken down. 

GDGs ground crew performed field surveys to identify temporary and permanent development sites. These sites were found in areas such as peatbogs, flooded forests, swamps, ruts, overflowing streams and ditchesMonitoring, treatment and post-monitoring continued throughout the spring and summer until every site in the protection zone was treated and verified 

Below shows the Treatment zone and the Protected zone for the Nuisance Mosquito Program: 

Treatment takes place when the larval egg has hatchedThis application is performed by air, using helicopters or drones and by ground using backpacks style sprayersA single application is usually good enough to achieve the 100% mortality of the spring larvae in most of the treatment areasSome small areas did require a post-treatment to achieve the 100% larval mortality.  

Monitoring results this year have shown that GDGs control strategy in areas like the Carp River and Beaver Pond area have improved significantlyAs well with the help of residents using the hotline or emailing, GDG has been able to discover new sites on private properties again this year 

Surveillance was performed by monitoring both the larval and adult mosquito stagesThe Post-treatment-larval surveillance provided information on the efficacy of larvicide, whereas the adult mosquito surveillance provided information on the locations of the development sitesThis information is helpful as it will improve the program throughout the next few years. 

Sweep tests were performed at the beginning of each week to confirm the number of mosquitoes caught in various areas in our communityThis type of test was used to identify the number of insects that could bite residents over a period of five minutes 

There were 8 locations throughout Kanata North that GDG routinely visited along with a student volunteer who acted as a witness to these weekly testsThe treatment is deemed effective when the average catch is less than 5 mosquitoesIf the capture rate is more than 15 mosquitoes, the test is considered a failure 

There was a total of 120 nuisance sweep tests performed during this seasons program with an average of 0.13 mosquitoes caught per test and 1.04 mosquitoes caught per night. 

CDC Light Traps were used to capture adult mosquitoes which helps GDG identify what species were in the areaBy knowing the specific species, GDG is able to better target their operationsCDC light traps use dry ice and an ultraviolet light to attract the mosquitoThese traps were installed in different locations within both the protected zone and treatment area in the afternoons and then collected the following morningsWhen the insect is collected it is then sent to the laboratory for species identification 

GDG previously believed that there needed to be a large rainfall in order to trigger mosquito egg hatching in areas like the Carp River, however, they have since discovered that a rainfall of as little of 20 mm can trigger a hatch in the right conditionsA treatment that follows a rainfall event now extends further up the Carp River and is performed more frequently in the wetlands that connect between and around the Carp River and Beaver Pond 

Overall, the 2020 mosquito season kept GDG quite busy, with great results for our community. I look forward to hearing how GDG plans to continue to improve the program for Kanata North residents.