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Single-brood Floodwater Innovation Gains Momentum


Single-brood control of floodwater mosquitoes has long been a particularly tough challenge for mosquito control districts. Just as species and habitat play a key role in effective control strategies, the insects’ stage of development is a critical factor. The more complex these variables, the more challenging it is to find an efficient and effective solution.

After two years of program integration and large scale trials, an advanced formulation combining Bti strain AM65-52 and (S)-methoprene (VectoPrime® FG) is having an impact in floodwater prone districts where asynchronous broods traditionally put a strain on resources.


In the Suffolk County area of New York, Aedes sollicitans and Ae albopictus are two of the dominant mosquito species, with a breeding season that runs from May 1 until the end of September. Tom Iwanejko, Director of the Suffolk County Vector Control Division, says the area also has extensive freshwater wetlands as well as salt marsh wetlands. In addition, Ae albopictus populations have risen sharply over the last three years and continue to expand in Suffolk.

After hearing of promising results from districts that used VectoPrime FG® for single-brood control in 2015, Iwanejko and his team were committed to evaluating the product for efficacy and operational efficiency in 2016. In March, Iwanejko began by bringing Jim Andrews, a technical specialist with the Public Health team at Valent BioSciences Corporation (VBC), out to the County to lead a training session on the new technology. Andrews and the team worked in a classroom setting to help them understand what VectoPrime is, how it works, and how sprayers should be calibrated to best deliver the product.


“We started with two crews and ran it [VectoPrime FG] out there for a test run,” Iwanejko says. “We saw excellent results — particularly with the later instars — so we incorporated it into the program for all 18 of our field inspectors and applicators.”

The results were well-received. While efficacy will always be his most important concern, Iwanejko says VectoPrime’s low application rate also brought the program much-needed efficiency. “Not only did we like the granules, but we were able to treat around four times more acreage per load than in the past,” Iwanejko says. “This saved the county a lot of staff time that would have been spent trekking back and forth to refill the backpack.”

Next season, the Suffolk County team plans to look into incorporating aerial applications into their treatment program, especially for the late season when the challenge is getting liquid spray droplets to penetrate the vegetation canopy.


The area of Ocean County, New Jersey contains mostly salt marsh and is home to a federal wildlife refuge and a state park. That means that environmental regulations are inherently more stringent then in many other locales. For this reason, the Ocean County Mosquito Extermination Commission has an ongoing need for solutions that are highly effective but are also low-impact on the surrounding ecology.

District Assistant Superintendent Mike Senyk says the County has traditionally relied heavily on bacterial larvicides as a cornerstone of its program, and since Bti and (S)-methoprene were both known to be low-impact, high efficacy products, the district decided to run a trial of VectoPrime FG in 2016.

“We heard the success stories form 2015 and liked the idea of how these two products would complement one another,” Senyk says. “We want strategies that work together instead of getting in the way of each other.”

The notion of combining Bti and (S)-methoprene is not new. Many districts have combined Bti and (S)-methoprene (a process known as duplexing) for single-brood control by either tank mixing liquid formulations or even spraying Bti granules with (S)-methoprene as it’s loaded into the hopper. VectoPrime® FG takes this approach to the next level by combining Bti strain AM65-52 and (S)-methoprene on a micron-scale. Using an innovative formulation technology known as BioFuse®, every micron particle of VectoPrime delivers an optimized ratio of both actives in the flexibility of a granule.

In the 2016 Ocean County Trial, a 24-acre barrier island marsh of Island Beach State Park was treated with VectoPrime FG by helicopter to control larval Ae sollicitans mosquitoes. Just prior to application, surveillance revealed mosquito larvae of the 2nd instar in the range of 11-30 larvae per dip. 48 hours post spray, the Ocean County team collected 50 pupae and placed them into an emergence jar to study the VectoPrime’s effects. The results showed just 10% emergence: Only 5 adults emerged while 39 pupae died and 6 adults died on top of the water.

Senyk says the 90% mortality rate was exceptional. He says a key to its effectiveness is the product’s ability to get into hard-to-reach areas. Much of the trial area is covered with a dense canopy of Phragmites that makes penetration into the water difficult, but the results were convincing. Senyk noted cost savings in man-hours as well as fuel costs, and says district will continue to utilize VectoPrime FG in their treatment program in 2017.


It hasn’t been an easy road for the Canyon County Mosquito Abatement District (CCMAD) headquartered in Nampa, Idaho. The District’s formation in 1997 was driven by residents that were plagued by extremely high mosquito populations in and around the Deer Flat National Wildlife Refuge. The Lake Lowell Mosquito Abatement District  became the Canyon County Mosquito Abatement District in 1998, and funding to operate its mosquito control program did not become available until 1999. The first budget to operate the program was limited and depended heavily on a crew of dedicated volunteers. Despite these humble beginnings, this grass roots effort is now a story of extraordinary success in the vector control community.

West Nile virus (WNV) would soon change the scope of work provided by the District. Over 1,000 human cases of WNV in Idaho during 2006 got the immediate attention of state legislators, which led to laws to support the formation and funding of mosquito control in 2007. This effort paved the way for the CCMAD to expand its operations to include all of Canyon County.

CCMAD Director Ed Burnett says the expanded territory brought with it new challenges including flood-irrigated pastures. These areas are difficult to access and are populated, at times, by asynchronous broods of mosquitoes that often include 4th instar larvae The District saw VectoPrime® FG as a unique tool for pre-flood applications necessary to treat areas that become inaccessible after water is present while maintaining control of late instar larvae, applications that have proven very effective for the District’s floodwater habitats.

CCMAD maximizes program efficiency by employing other advanced technologies such as GPS tracking of adulticiding operations, computerized recordkeeping of its larvicide applications, and a robust
surveillance program that complement the use of new products such as VectoPrime.