Caught in the Act

CDC PHIL of larval surveillance- https://phil.cdc.gov/Details.aspx?pid=2

The times they are a-changin’, including the number of days hospitable to mosquitoes.

Climate Central analyzed the number of days perfect for mosquitoes (between 50-95 degrees Fahrenheit) and found that 64 percent of the 239 locations studied had more mosquito days in the 2010s compared to the 1980s. The increased number of days means increased opportunity for mosquitoes to bother people, or worse, make someone sick.

With increased mosquito days comes increased demand for mosquito control services, and pest management companies are standing up to meet this demand. The 2021 State of the Mosquito Market Report, published by PCT in May 2021, showed that from 2014-2020, pest control companies offering mosquito control increased from 38 to 73 percent. Now that more companies offer mosquito control services, the question becomes, “What is the best way to manage mosquitoes?”

Like most control programs, the best way to manage mosquitoes uses an integrated approach. Science-based mosquito control, or integrated mosquito management (IMM), uses data to create plans that utilize multiple tools to prevent and kill mosquitoes. Using this approach, technicians reduce mosquitoes while minimizing the impact on the environment by only using pesticides when the data supports need.

A fundamental component to any IMM plan is surveillance, which is the regular monitoring of all mosquito life stages throughout the entire mosquito season. Mosquito surveillance provides companies valuable information to:

1. Detect increases or decreases in mosquito populations.
2. Detect if the mosquito species collected changes over time.
3. Determine if the environment contains mosquitoes that bite humans. (Not all mosquitoes bite people!)
4. Determine what control measures to use and when.

Incorporating surveillance into a mosquito control program can be challenging though, and the 2021 report reflects this (only 18 percent of respondents reported offering surveillance). Mosquito surveillance takes more time at an account compared to other services, possibly even requiring two visits a month instead of just one. Additionally, once traps have collected mosquitoes, companies need specific expertise to identify species and determine how to use the data. Finally, some customers may demand treatment. After all, they called you to treat, not tell them what kind of mosquitoes they have, right?

However, a recent report from FieldRoutes revealed that about one-third of pest control purchasers searched for environmentally friendly pest control, suggesting customers may want options that do not solely rely on insecticdes. This means a company might be able to carve a niche for itself by educating customers about surveillance and data-driven mosquito control. To help, below are just a few ideas about how to take a stab at mosquito surveillance today. What follows are some ways to start collecting data.

Immature surveillance. All mosquitoes require water to complete their life cycle, so surveillance should start by regular, ongoing inspections of the property for current and potential mosquito habitats. Have the inspector bring a piece of grid paper, create a sketch of the property and mark water/larvae findings. Make sure to capture relevant information such as date and time, type and size of water source, and treatments performed. Keep this document and record the next inspection data over the original with a new pen color. If visually capturing this data proves challenging, start by making notes on the service report as a way to track data over time.

The historic data will inform treatment decisions and visualize ongoing problems with the property. Use this information next year to remind the customer when their mosquito season may start. With enough historic data, technical experts may identify trends in the area that marketing can use to recruit new customers.

Leigh-Anne Lawton

Adult surveillance. More sophisticated traps, such as Center for Disease Control and Prevention Light Traps, can collect several adult mosquito species and provide data for a larger area (e.g., a neighborhood).

To begin, set one trap and identify the mosquito species collected. Different species will dictate treatment range and if technicians should set additional traps. For instance, traps may collect Culex quinquefasciatus mosquitoes from more than a mile away, possibly justifying treatments for homes in a radius that’s larger than 1 mile. However, traps that collect Aedes aegypti mosquitoes suggest the problem is much closer (about 55-110 yards away). In this instance, the technician should speak to the residents in the immediate area, and if possible, treat their homes or choose to set more traps to estimate the necessary treatment area.

If manually servicing traps proves too time consuming and labor intensive, commercially available smart traps may help solve this problem. These traps can distinguish mosquitoes from other insects and wirelessly transmit count data. Unfortunately, they still have limitations such as not being able to identify mosquitoes’ species. However, future innovation may overcome these limitations and reduce the labor and time required to perform adult mosquito surveillance.

Customer interviews. Regularly surveying customers can create a dataset that could help inform treatment decisions. As part of the monthly service, the technician could ask the decision maker questions and record the answers in a journal, simultaneously building value with the customer while collecting important data about the account.

Example questions may include: Are you getting bitten? How often are you bitten? When do you get the most bites: daytime, dawn/dusk or night? Did you see what bit you? Do you have a picture? What did it look like? Alternatively, automated programs can send surveys ahead of the visit asking these questions.

Technical experts can use the answers to help categorize the types of mosquitoes plaguing the customer, gauge if the problem is getting better or worse and determine possible treatment decisions.

Additionally, comparing answers between seasons could help predict when complaints will start coming in next mosquito season. Just remember that ideally, customer requests alone should not result in pesticide application.

TALKING POINTS. Companies that educate customers before, during and after the mosquito season manage expectations (e.g., reducing, not eliminating, mosquitoes) and help customers understand the importance of mosquito surveillance and using data to determine the treatment. Consider these talking points when explaining to customers the value of surveillance-based control.

Mosquito surveillance lets experts estimate populations in an area and make the best decisions for the customer and environment. If mosquito numbers are low, using repellents, large fans or managing standing water in a backyard may prevent bites and unnecessary pesticide applications.

Mosquito control programs should start before mosquito season, including surveillance. Preventing bites can start by delaying when mosquitoes will appear. PMPs and customers should prepare during colder weather, so emerging mosquitoes cannot lay eggs, delaying new adults as long as possible.

When talking to homeowners associations or recruiting multiple homes in an area, explain that performing surveillance for an entire neighborhood and treating a larger area will result in better mosquito control for individual homes. After all, mosquitoes do not respect property boundaries.

Regular larval inspections allow technicians to address mosquito sources and possibly uncover costly ticking time bombs. A broken sprinkler system or leaking septic tank can create mosquito larval habitats, but also cost people hundreds of dollars in water bills and replacement costs.

FINAL THOUGHTS. Any surveillance is better than no surveillance. There will always be better ways to execute, and the best way may not always be easy or reasonable. However, any effort to make data-driven decisions is a step in the right direction and could result in better management of mosquitoes, build value with customers and minimize the impact to the environment.

Additionally, with increasing regulatory scrutiny around pesticides, pest control companies that make data-driven decisions about when to use insecticides act as product stewards and protect the availability of these products on the market. On the other hand, treating a yard with insecticides without any supporting data risks introducing unnecessary contaminates into the environment, impacting non-target organisms, creating higher pesticide costs and selecting for insecticide resistance.

Regardless of the method, mosquito surveillance requires time to perform. For this reason, monthly service for mosquito accounts may become a two-day job instead of just one. This may mean more cost to service a single account. However, the upside could mean mosquito control becomes a premium service that commands a premium price. Surveillance-based mosquito control will not always be easy, but any efforts to start making data-driven decisions could create benefits that make the reward worth the challenge.

Jennifer R. Gordon earned her B.S. in entomology from Purdue University, her M.S. in entomology from Louisiana State University and her Ph.D. in entomology from the University of Kentucky. She is founder and principal consultant at Bug Lessons Consulting. Learn more at buglessons.com.

References:

1. Central, C. (2020). This News Bites: More Mosquito Days. Climate Central. Retrieved April 15, 2021, from https://medialibrary.climatecentral.org/resources/more-mosquito-days.
2. PCT. (2021). 2021 State of the Mosquito Control Market. Pest Control Technology. Retrieved May 7, 2021, from https://giecdn.blob.core.windows.net/fileuploads/document/2021/05/07/2021%20mgk-mosquito-market%20report.pdf.
3. AMCA. (2021). Best Practices for Integrated Mosquito Management. AMCA. Retrieved Nov. 15, 2021, from https://cdn.ymaws.com/www.mosquito.org/resource/resmgr/docs/publications/hr_november_2021_amca_bmp_ma.pdf.
4. Flores, C. (2015). Mosquito Surveillance for Effective Mosquito Population Control. Vector Disease Control International. Retrieved Feb., 22, 2022, from https://www.vdci.net/blog/mosquito-surveillance-for-effective-mosquito-population-control/.
5. Routes, F. (2021). 2021 Consumer Pest Control Purchasing Report. Retrieved from https://www.fieldroutes.com/resources/reports/consumer-pest-control-purchasing-report?cid=7015G000001OZs8QAG.
6. Ciota, A.T., et al. (2012). Dispersal of Culex mosquitoes (Diptera: Culicidae) from a wastewater treatment facility. Journal of medical entomology, 49(1), 35-42.
7. Reiter, P., et al. (1995). Dispersal of Aedes aegypti in an urban area after blood feeding as demonstrated by rubidium-marked eggs. The American Journal of Tropical Medicine and Hygiene, 52(2), 177-179.