City of Longmont

In 2002, City Council voted in favor of establishing a formal mosquito control program in the City of Longmont. The purpose of the program is to protect residents from disease and annoyance through a comprehensive Integrated Pest Management approach. The 2009 larval coverage area for the City of Longmont included approximately 28 square miles of private and public lands in the city limits of Longmont. In 2009 the City of Longmont and Boulder County Public Health agreed to cost share larval control efforts in a portion of unincorporated Weld County. The Weld County Service Area encompasses 9 square miles of unincorporated lands, east of County Line Road and south of Ute Hwy. Both entities recognize that this area presents a significant number of larval mosquito habitats, which can produce mosquitoes that will migrate into Longmont city limits and Boulder County. To date, 401 larval mosquito habitats are included in the regular inspection and larviciding program for the City of Longmont Mosquito Management Program. There were 11 new larval sites added to the routine inspection program in 2009. To date, 71 larval mosquito habitats are included in the regular inspection and larviciding program for the Weld County Service Area.

Program Goals The primary objectives of the City of Longmont Mosquito Control Program is to suppress the development of larval mosquitoes in wetland and other sites, conduct surveillance of adult mosquito populations and provide limited adult mosquito control when predetermined disease and annoyance thresholds have been surpassed. These objectives are reached using a framework of Integrated Pest Management whose goal is to provide the greatest level of control of pest and disease vector mosquito populations while maintaining a balanced use of cultural, biological, and least-toxic chemical procedures that are environmentally compatible and economically feasible.

Services provided to City residents:
• Information about mosquito biology and source reduction of mosquito habitats
• Information on mosquito control and monitoring efforts within the city
• Seasonal West Nile Virus activity
• Information about personal protection for mosquito annoyance and West Nile Virus risk
• Arrange routine habitat inspections at residential backyards, catch basins, retention ponds on either city or private property with permission
• Perform application of mosquito control products using Integrated Pest Management (IPM) methods and target specific controls on mosquito larvae at no cost to the property owner
• Respond to reports and concerns of mosquitoes and possible mosquito habitats
• Stock residential ponds with fat head minnows for biological control
• Advanced call notification of spraying and exclusion of your property from spraying
• Spray schedules

2009 Season Perspective
The higher-than-normal levels of precipitation during the 2009 season replenished the water table to levels not seen in years for many areas along the Front Range. Rainfall totals remained above average for a majority of the 2009 mosquito season. Although most of the rainfall occurred in early April and June, additional weekly rainfall created numerous larval mosquito habitats and kept things green throughout the season. With the excess moisture came a corresponding above-average workload for larval mosquito control activities, due to the flushing and refilling of aquatic habitats on a regular basis. In general, many reservoirs and ditches remained full for a large portion of the summer, because irrigation water was not moved as quickly. Many grassy edges and inlets to reservoirs were consistently producing mosquito larvae throughout most of the season. Working with local farmers to understand and recognize the patterns of agricultural irrigation continues to be one of CMC’s ongoing priorities. In 2009 91.3% of the total sites inspected in the City of Longmont were wet upon inspection and 53.3% were producing mosquito larvae. Mosquito populations in the first part of the 2009 season consisted of primarily Aedes spp., known as “floodwater” mosquitoes as their eggs hatch in response to rising water levels resulting from rainfall and/or irrigation. Adult Culex mosquito populations spiked in mid-July. Overall, vector mosquitoes comprised about 50-75% of mosquito collections during July and August, remaining in line with historical averages. This scenario could have played out much differently had the median temperature during early spring been warmer, as occurred in 2003 when the vector Culex mosquitoes had an early population spike. 2009 was different in that we had similar moisture levels, but without the corresponding high temperatures of the 2003 “WNV epidemic” season.

The first West Nile Virus infected mosquitoes were detected in Weld County on July 10, Boulder County on July 13, and Larimer County on July 14. West Nile infection rates in mosquitoes remained below epidemic years and the Colorado Department of Health and Environment (CDPHE) ceased WN testing of mosquitoes on August 14. Dip counts for larval mosquitoes slowed into late August. By the first days of September the species composition of Culex mosquitoes collected from adult trapping dropped to less than 10% of the total counts in most areas.

Fathead Minnow Program
Residents are encouraged to call 970-962-2583 to request a CMC technician to stock ornamental ponds. Fish will be provided in June each season. Please ensure that your pond is at least 3 feet deep, does not contain koi, blue, or other predatory fish, and possesses a soil base bottom so that the fish can survive the winter.

2009 Surveillance Trapping Operations
Data on mosquito abundance and species identity is critical in the operation of a successful mosquito management program. Over the past few years, identifying, packaging, and sending Culex mosquito pool samples to the CDC/CDPHE labs for West Nile Virus testing has also become critically important in the battle against West Nile Virus and other mosquito-borne diseases. The purpose of a surveillance program is to be an early warning system. In other words, the system is intended to alert mosquito personnel of an impending health crisis. The key is that the system gives enough advance warning that mosquito control personnel can work with County Health Departments and city officials to take effective steps in minimizing the number of human cases.

In 2009, Colorado Mosquito Control monitored a statewide network of over 250 trap sites, with over 3,100 trap nights set, collecting more than 499,000 adult mosquitoes that were counted and identified to species by the CMC Surveillance Laboratory. While individual traps provide only limited information, trap data is interpreted in the context of historical records for the same surveillance location, going back in time more than a decade in some locations. Individual traps are also compared to other traps from around the region that were set on the same night and therefore exposed to similar weather conditions. Technicians working in the Surveillance Laboratory at Colorado Mosquito Control, Inc. are trained to provide accurate species identification of mosquito specimens for both adults and larval mosquitoes. More than 50 mosquito species are believed to occur in Colorado and 20 of those were identified from samples processed during the 2009 season from across the state.

CMC employs two kinds of traps to monitor mosquito populations. The CDC light trap uses carbon-dioxide from dry ice as bait to attract female mosquitoes seeking a blood meal from a respiring animal. Once attracted by the CO2, the mosquitoes are lured by a small light to a fan that pulls them into a net for collection. The gravid trap uses a tub of highly-organic water as bait to attract female mosquitoes that are looking for a place to lay their eggs. A fan placed close to the water surface forces mosquitoes that come to the water into a collection bag.

Targeted Ultra-low Volume Adult Mosquito Control

The goal of Colorado Mosquito Control, Inc. is to provide all residents of the City of Longmont with the best options for safe, effective, modern mosquito management. The primary emphasis of the City of Longmont Mosquito Control Program is to control mosquitoes in the larval stage, using safe biological control products. This environmentally focused program maintains adulticiding applications as a final resort when mosquito populations surpass West Nile Virus risk thresholds. Mosquito surveillance trapping results are used to make data-driven decisions regarding areas that need to be sprayed for adult mosquito control. Adult mosquito control spraying is targeted to specific sectors determined by this trap data, thereby reducing the area sprayed and the frequency of spraying in each sector. Over 95% of the Longmont Mosquito Control Program is targeted against larval (aquatic stage) mosquitoes utilizing biological control materials. However, on occasion adult mosquito spraying becomes necessary.

City officials work cooperatively with CMC to monitor mosquito surveillance and West Nile Virus transmission activity in vector populations. If deemed necessary by city officials and Public Health supervisors, Colorado Mosquito Control utilizes 3.3% Permethrin in ultra low volume (ULV) spray applications via truck mounted fogging machines. ULV sprayers dispense an extremely small amount (0.0035 pounds per acre) of fine aerosol droplets which stay aloft and kill adult mosquitoes on contact.

CMC worked with the Daily Times Call to provide resident notification of mosquito adulticide applications again in 2009. CMC utilized mosquito trapping data collected on Sunday evenings each week, for reporting to the City of Longmont on Mondays. The City of Longmont would make decisions, based on mosquito trap counts, as to the areas to be included in mosquito spraying for that week. CMC communicated the areas to be included to the Daily Times Call for posting in the Times Call on Tuesdays. CMC also posted the spray schedules for the City of Longmont on CMC’s website on Mondays and the day of applications. All mosquito spraying was scheduled and performed on Wednesday evenings in 2009.