Operations Observations:

Single-brood Floodwater Mosquito Control Challenges

Single-Brood Operational Efficiency Calculator

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Single-brood/floodwater mosquitoes, such as Aedes vexans, present two fundamental challenges for public health professionals involved in mosquito control.

First, larvae often hatch and develop at different times and rates, which complicates strategies for treatment timing and larvicide product selection. Second, floodwater habitats can be extremely unpredictable. Flooding patterns can vary greatly based on rain patterns, tidal events, irrigation timing, etc. Consequently, labor-intensive field surveillance is often necessary to detect flooded habitats and the dominant life stages present (from 1st to 4th instar) before larviciding can begin.

As a result, public health professionals are faced with the following unknowns when developing their IVM strategy for single-brood, floodwater mosquitoes:

As a result, public health professionals are faced with:

  • Surveillance Demands – Continual surveillance may be required to monitor asynchronous broods
  • Operational Complexity – Reacting to changing conditions typically requires greater effort and resources than less dynamic conditions
  • Product Selection – Different solutions for early/late instars – switching costs


Bottom line, more unknowns usually equates to higher program costs.

How are today’s mosquito abatement directors and operations managers addressing this challenge.

Case Study: Pinellas County Single-brood Trials Yield Positive Results

Asynchronous, single-brood floodwater mosquitoes present a unique set of challenges in Florida’s Pinellas County. Not only do larvae within the Aedes and Culex populations hatch and develop at different times and rates, the variability of flood patterns exacerbates the issue.

In February 2015, Valent BioSciences (VBC) introduced VectoPrime® FG to help Public Health professionals combat these challenges.

VectoPrime takes an innovative approach to mitigating the variability brought about by floodwater “unknowns.” A next-generation biorational larvicide, VectoPrime offers complete single-brood control that can also be applied pre-flood. This biorational larvicide combines Bti strain AM65-52 with (S)-methoprene in each micro particle by utilizing VBC’s patented BioFuse™ technology. As a result, VectoPrime FG offers the industry’s widest single-brood application window (1st to 4th instar, or pre-flood) with the industry’s lowest rates for direct application to water, thus saving significant operational costs while improving application flexibility.

Pinellas investigators conducted two trials:

1) a microcosm trial using buckets
2) a field trial conducted in the salt marsh ecosystems in the county.

Microcosm Trial Key Results

Nearly all the Aedes larvae (all instars) died in the first eight hours post-application, whereas nearly all the Culex larvae died in the first 10 hours. There was no significant mortality in the untreated control bucket.

Field Test Key Results

Only eight dipping locations contained larvae, so only these dipping locations were used for efficacy assessment. The buckets placed in the flagged locations confirmed that the VectoPrime application reached all eight locations. No living Aedes or Culex larvae were found 24- or 48-hours post-application in any of the eight dipping locations, indicating 100% mortality.

Case Study: Ocean County Getting a “Double Dose of Bti”

Mike Senyk is the Superintendent at Ocean County Mosquito Control in Barnegat, New Jersey.

In the early 2000’s, Ocean County Mosquito Control would apply liquid larvicides to open salt marsh habitats, but rising sea levels/water keeps pushing up the lower marsh. As such, this habitat is no longer “pocketed” which results in easy flow of fish/minnows across the lower marsh which are doing a good job of keeping mosquito larval populations down. Water is now pushing into the “transition” or “tree-line” zone. Public Health professionals in Ocean County now needed to apply larvicide in areas that are harder to reach due to vegetation, and have thus switched to granule larvicide applications.

Ocean County began aerial applications with VectoBac® GS but found that they needed to make two applications to the same area at 4 lbs. per acre due to difficulties in changing their aircraft hopper equipment/plate configuration (i.e. applying an 8 lb/acre rate).

After learning about VectoPrime and the operational efficiencies its BioFuse™ technology delivered, Ocean County calculated that a switch to VectoPrime would significantly improve their payload and thus save significantly on their operational costs.

Now with VectoPrime, Ocean County can apply 4 lbs/acre — once.

In addition, Ocean County feels that VectoPrime provides them control:

  1. early in the season when metabolism of the larvae is not as high,
  2. later in season (e.g. August) when organics/algal blooms are high and
  3. when dealing with high larval populations


“You get assurance with the integration of (S)-methoprene,” says Mike. “If you’re on a tight schedule, you have that advantage with Prime. It is beyond the perfect replacement for Abate.”

Improve Your Floodwater Mosquito Control Operations

Interested in learning more about VectoPrime and exploring whether your program can realize operational cost savings and increase efficiency?

Complete the form below to connect with a Valent BioSciences representative to see how they can provide you with a custom operational savings report (OSR) utilizing Valent BioSciences’ Single-Brood Program Savings Calculator.

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