The Town of Johnstown s Mosquito Management Program

Transcription

1 The Town of Johnstown s Mosquito Management Program The Town of Johnstown Mosquito Management Program completed its 7th year of cost effective biorational integrated mosquito management operations in 2010 with Colorado Mosquito Control as its contractor. Mosquitoes are dynamic insects which are capable of rapid populations increases dependent on habitat, water level, rainfall events, and temperature patterns. The experience and knowledge possessed by CMC employees for the local land use and irrigation patterns, enables an overall reduction of mosquitoes. The biorational management operations and data driven response to spikes in mosquito abundance are aimed at reducing the risk and annoyances associated with mosquitoes. If left unmanaged residents residing throughout large sections of the town would be burdened by mosquitoes, thereby resulting in a decreased quality of life and reduced ability to enjoy outdoor activities. The objective for the Town of Johnstown Mosquito Management Program is to utilize trained field biologists to suppress the number of mosquitoes, in the aquatic larval habitats. This reduces the potential for mosquitoes to emerge from the water to feed on and reduce the transmission of vector borne diseases to the residents of Johnstown. The Town of Johnstown monitors adult mosquito populations via a surveillance trapping network to enable a proactive response to suppress West Nile Virus vector mosquito populations prior to a public health emergency outbreak. Adult mosquito population data provides real time information regarding the nuisance and risks associated with mosquito populations in Johnstown. Trapping data provides a scientific basis when determining the need to reduce the mosquito populations via adult mosquito control materials. CMC sets 5 mosquito surveillance traps in the Town of Johnstown on a weekly basis to monitor the mosquito counts within town. This objective enables a decline in the overall mosquito populations, while reducing the threat of mosquito borne disease transmission, at the least possible cost, and with the least possible impact on the people and natural environment. CMC will continue to strive and demonstrate a commitment to Integrated Pest Management principles for a progressive approach to mosquito reduction.

2 Please call or to report any water that stands for more than 4 days, mosquito annoyance concerns, or for information regarding West Nile Virus prevention. Resident phone calls continue to locate new mosquito habitats, thereby reducing the number of mosquitoes in the backyards of Johnstown residents. Service Area The larval control area for the Town of Johnstown encompasses approximately 7.2 square miles within town limits. To date 156 larval mosquito habitats are included in the regular inspection and larviciding program for the Town of Johnstown Mosquito Management Program. The program can provide services to residents in town limits regarding: Information about mosquito biology Information about mosquito control, monitoring efforts, trapping data for mosquito counts, & spray schedules Seasonal West Nile activity updates Options for personal protection from mosquito annoyances and West Nile Virus risk Inspection and application of mosquito larvicides or provide bio-controls for target specific management of mosquito larvae Respond to reports and concerns of possible mosquito habitats

3 The History Program behind the Mosquito Management Johnstown s Integrated Mosquito Management program focuses on utilizing naturally occurring soil bacteria, larvicides, to control mosquitoes in the larval stage, instead of relying entirely on application of pesticides in the form of fogging materials. The program primarily utilizes applications of Bti, a stomach toxin, which is target-specific to larval mosquitoes. This naturally occurring bacteria is activated by a specific ph within the larval gut and disrupts the larvae s ability to consume and digest food resources. Field technicians methodically inspect larval habitats twice a week, weekly, bi-weekly or post rainfall, as deemed necessary based off of historical data. A technician may spend the day inspecting a variety of habitats ranging from urban mosquito breeding locations (storm drains, catch basins, wading pools, paddle boats & tire piles), as well as cattail marshes, stagnant ditches, reservoir edges and irrigated pastures. Inspections are performed to determine whether larval mosquitoes are present or not at a site. Once the presence of mosquito larvae is confirmed, larvicides are applied. This enables targeted control, while reducing the miles of city streets that need to be fogged for adult mosquitoes. When properly carried out, by trained applicators, IPM programs return beneficial results in reduced pesticide use, reduced frequency of pesticide resistance, and reduced exposure to pesticides by the environment. The Mosquito Management Program offered by CMC follows successful IPM principles for cost effective, scientific methods of survey/inspection, evaluation, diagnosis, application and record keeping of materials used 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 Colorado Department of Health and Environment (CDPHE) Lab for West Nile Virus testing has also become critically important in the battle against West Nile Virus and other mosquitoborne 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 advance warning that mosquito control personnel can

4 work with County Health Departments and town officials to take effective steps in minimizing the number of human cases. In 2010, Colorado Mosquito Control monitored a statewide network of over 250 trap sites, with over 3,200 trap nights set, collecting more than 425,000 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. 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 Surveillance Light Trap Data Comparison In 2010, an average of 5 surveillance light trap locations monitored adult mosquito populations within the Town of Johnstown. Weather permitting, CDC batteryoperated light traps were set weekly in each location to provide adult mosquito population data for seasonal comparisons. Surveillance trapping began May 27 th and trapping was concluded on September 2 nd. There were 72 successful surveillance traps set which collected a total of 17,704 mosquitoes from within the Town of Johnstown. The average number of mosquitoes caught per trap per night was 246 and the average Culex mosquitoes caught per trap per night was 47. The composition of mosquitoes trapped was 17.1% (3,026) Culex tarsalis, 1.8% (317) Culex pipiens, 80.8% (14,307) Aedes/ Ochlerotatus spp. and.2% (44) Culiseta spp.

5 Targeted Ultra-low Volume Adult Mosquito Control Adult mosquitoes can come from unknown unidentified sites or may migrate in from uncontrolled areas. Johnstown uses all available data from CDC light traps, Mosquito Hotline annoyance calls, and field technician reports to focus adult mosquito control efforts on specific, very limited targeted areas. In parts of the community were high numbers of mosquito annoyance calls are received, floater CDC light traps are set to evaluate adult population levels and species make-up. In most cases, a direct correlation is evident between areas with high complaint calls and high trap counts. While this correlation allows us to focus adult control in these areas, the emphasis is placed on finding the source of breeding and continued larval control measures. Over 95% of the Johnstown s Mosquito Control Program is targeted against larval (aquatic stage) mosquitoes utilizing biological control materials. However, on occasion adult mosquito spraying becomes necessary. At that point 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 ( pounds per acre) of fine aerosol droplets which stay aloft and kill adult mosquitoes on contact.

6 Permethrin is a synthetic pyrethroid similar to the insecticide pyrethrum which occurs naturally in chrysanthemum plants. Permethrin is found in a variety of products, including household insecticides, flea dips, repellents for clothing, sprays for pets, and lice shampoos. This pesticide has been selected to achieve effective control of mosquitoes and suppression of West Nile Virus transmission with the least impact on human health and the environment. Fogging applications are performed based on mosquito populations caught in traps on a nightly basis. The town is divided into zones. Specific neighborhoods are fogged when surveillance traps catch 100 floodwater mosquitoes, referred to as a Nuisance Threshold or 50 Culex mosquitoes, referred to as a Disease Threshold. The thresholds for fogging applications are established by an industry standard that measures vector and nuisance mosquito populations. Colorado Mosquito Control uses state of the art technology, correct application timing, and least-toxic products to minimize non-target impacts. All adult mosquito control is accomplished using calibrated Ultra Low Volume (ULV) equipment and performed after dusk. This type of equipment produces droplets averaging 12 microns in diameter and allows for a minimal amount of product to be put into the environment. These treatments take place in the evening when mosquitoes are flying in greater numbers and non-target activity is greatly reduced. Using this application technique, the overall goal of minimal environmental impact and effective adult control is achieved in the targeted area. All insecticides used by Colorado Mosquito Control are registered by the EPA and the Colorado State Department of Agriculture. For additional information regarding permethrin, including toxicology data please visit: and click on the tab for pesticides.

7 Notification and Shutoff Services Upon request, residents can be notified prior to spraying with Permethrin insecticides. Call & Shutoff forms are available online and may be submitted via CMC website or by mail. Please note that a shutoff does not guarantee that drift of insecticide material will not occur and may decrease the effectiveness of adulticiding in your immediate area. Please note that the call shutoff list is a service that CMC provides to residents and may be obsolete in the case of a West Nile Virus Public Health emergency, as experienced in 2003/ For additional information regarding permethrin, including toxicology data please visit: and click on the tab for pesticides. Technology In many municipalities the link to CMC s dashboard from the contracted areas webpage has provided transparency of data for mosquito control operations directly to the residents. From the dashboard, data for specific mosquito traps, acres of larvicides applied, ULV miles sprayed and West Nile Virus positive mosquito locations can be accessed from the page options. Interactive reports on the dashboard are updated on a daily basis to contain all current data throughout the season. CMC encourages the distribution of this link to enable faster reporting about operations and answers to inquiries from the community. Free Fish Stocking Program CMC will continue to work with Johnstown residents to supply larvivorous fish to those residents with ornamental and closed-system ponds that are not currently stocked with fish and that may be producing mosquito problems in their neighborhoods. CMC technicians will physically visit the resident s homes to distribute fish and confirm that the pond is a viable habitat for fish. Fathead minnows are the preferred fish for this application because they are native to Colorado, prominently found in the Platte, Republican, Arkansas and Rio Grande basins. Minnows also have high reproductive success and are tolerant of various habitats. A single fathead minnow can consume up to 600 mosquito larvae an hour, thereby providing another biological control in ornamental ponds. The fathead minnow averages a life span of 3 years.

8 Prevention & Protection Presentations CMC offers all resident committees, homeowner s associations, or employers the option to have a member of CMC staff provide informative presentations about personal protection, repellents, West Nile Virus activity and ways to reduce mosquitoes by dumping/ draining standing water. These presentations work in conjunction with the Colorado Department of Health and Environment s Fight the Bite campaign. CMC can also provide specifics about mosquito control operations and data for a given area of Loveland to any person whom requests. Please call for more information or to schedule a presentation time. Backyard Inspection Program CMC employs a technician solely assigned to inspecting residential backyards and educating residents about the Fight the Bite campaign. Backyard inspections will reduce container breeding WNV vector mosquitoes and increase public contact and program involvement.