April 27, 2022
City of Mansfield Council Members,
Approximately forty-five percent of the population of Tarrant County resides in the City of Fort Worth. Fort Worth has about ten times the population and land area as compared to the City of Mansfield. Mansfield has twelve mosquito trapping locations of which six are tested weekly as compared to Fort Worth’s seventy plus sites.
With these statistics one would not be surprised if Fort Worth had ten times the ground spray events as compared to Mansfield. It would stand to reason with Fort Worth being ten times larger in land area and mosquito trapping locations. That is not the case at all. During 2021 the City of Mansfield resorted to ground spraying sixty-two times with twenty of those events at a one mile radius as compared to Fort Worth’s thirty-six times with all of those confined to one-half of a mile.
One would question why Fort Worth not only did not have ten times the ground spray event but had forty-two percent less spray events in total than a city one tenth its size.
The reason is that the two cities have very different mosquito control programs. The City of Fort Worth has a robust preventative control program that follows EPA guidelines that were described in a previous letter and the City of Mansfield seems to promote a reactive, wait until things get bad enough, ground spray response.
The City of Fort Worth will tell you that the only part of Tarrant County Public Health’s mosquito control activities that they follow are mosquito trapping and testing and that preemptive larviciding is “an extremely important part” of their mosquito control program. After adopting the proactive program areas where positive traps were commonplace are now rare.
A robust larviciding program goes far beyond treating a few back yards. Larviciding locations should include creeks, drainage ditches with water, creek road crossings and anywhere with standing water. Fort Worth currently follows the following schedule for applying larvicides:
1. Areas that had positive traps the previous year or historically produced positive traps are larvicided for a one-half mile radius monthly throughout the season.
2. As mosquito trap numbers increase those areas are larvicided for a one-half mile radius.
3. A positive trap location will be larvicided for a one-half mile radius.
4. Ground spraying will be used only after two or three consecutive positive traps. The reason for this delay is to give larviciding time to take effect in greatly reducing new mosquitoes entering the environment as current adult mosquitoes are naturally dying off.
This comparison demonstrates how following EPA recommended mosquito control guidelines can and will yield widely varying results as compared to the least effective, most costly and most toxic response.
There are two attachments to this letter. One is of a typical area that would be included in a larviciding program and the other is a typical letter to residents in an area the uses larviciding as primary mosquito control.
Thank you,
Larry McFarland