Mosquito Control

City of Ennis Department of Health Services


The City of Ennis Department of Health Services has an active program for assessing the numbers and types of mosquitoes within the City.  The Department’s staff is licensed through Texas Department of State Health Services to purchase and apply insecticides for public health protection.  Licensure requires annual classroom training of staff on the safe use and application of pesticides About the Pesticides We Use. The Department utilizes Integrated Pest Management (IMP) approach in Mosquito Control Mosquito_Control_Items.

In addition staff must be able to demonstrate knowledge of the biology and ecology of mosquitoes, to apply monitoring techniques and to establish what type of monitoring and/or control measures to employ and how to evaluate the effectiveness of the monitoring and/or control measures applied.

Each week, City staff sets out approximately 8 traps throughout the city. The number of mosquitoes trapped at each location is logged, and each trap net's catch (called a "pool" of mosquitoes) is shipped to the Texas Department of State Health Service's laboratory in Austin for testing.  Mosquitoes are tested for the West Nile Virus (WNV), St. Louis encephalitis (SLE) and several other mosquito-borne viruses.

To report stagnant water or request a trap to sample mosquitoes, contact the City of Ennis Department of Health Services at 972.875.1234. Both the federal Centers for Disease Control and Prevention (CDC) in Atlanta, and the Texas Department of State Health Services in Austin have written guidelines and regulations that relate to municipalities’ and county governments’ use of airborne pesticides (truck-mounted sprayers). This form of mosquito control is known as “adulticiding” or killing adult mosquitoes.

Though most U.S. cities used adulticiding throughout the latter half of the twentieth century to reduce “nuisance” mosquitoes (those species that bite humans but normally don’t carry disease), nuisance spraying is heavily discouraged by state and federal health officials.  The City of Ennis has adopted the recommendations of the CDC when deciding when to use the truck-mounted adulticiding spray unit.

These guidelines are as follows:

  • When a particular trap location has over 100 female mosquitoes in one night of trapping.
  • When a mosquito pool (one trap’s catch of mosquitoes) has tested positive for either WNV or SLE.
  • When the county or state health department reports a suspected human case of WNV or SLE in Ennis.
  • When the county or state health department reports a confirmed human case of WNV or SLE in Ennis.

In May of this year (2015), the City of Ennis Department of Health Services staff began monitoring mosquito populations captured in live mosquito traps throughout various locations around the City.  At this time (October 2015), there have been three mosquito traps that have tested positive for the West Nile Virus, to date there have been no reported human cases of West Nile Virus within the City limits.

For more information, please call the Department of Health Services at 972.875.6442. You may also contact us to schedule a treatment of stagnant bodies of water in public areas.  City staff will treat the area within 48 hours.

2016 Presentations to the City Commission:

    1. The Zika Virus 2016

    2.Mosquito Control Update 2016



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For more information about mosquitoes and West Nile virus, visit