FourStar® Bti CRG - 8 lb./acre
- arthuroslund2
- Sep 5
- 4 min read
Updated: Sep 19
The Collier Mosquito Control District (CMCD) carries on extensive spraying of FourStar Bti CRG in Collier County residential areas.
Bayview park | 4/1/2025 |
Pelican Bay | 4/1/2025 |
Wiggins Pass | 4/1/2025 |
Windstar Country club | 4/1/2025 |
River Reach | 4/2/2025 |
North Road Area | 4/8/2025 |
Little Hickory | 4/24/2025 |
Barefoot Beach | 5/4/2025 |
Wiggins Pass | 5/4/2025 |
Gordon River Greenway | 5/5/2025 |
Gulf Harbor | 5/5/2025 |
North Road | 5/5/2025 |
Pelican Bay | 5/5/2025 |
Anchorage Swamp | 6/5/2025 |
Barefoot Beach | 6/5/2025 |
Gulf Harbor | 6/5/2025 |
Pelican Bay | 6/5/2025 |
Bayview | 6/6/2025 |
Botanical Gardens | 6/6/2025 |
Little Hickory | 6/6/2025 |
Port Royal | 6/6/2025 |
Sandpiper Street south | 6/6/2025 |
Wiggins Park | 6/6/2025 |
Windstar Country Club | 6/6/2025 |
Port of the Islands | 6/10/2025 |
Barefoot Beach, Gulf Harbor, Little Hickory and Vanderbilt Drive | 7/10/2025 |
Wiggins Pass are | 7/15/2025 |
Wiggins Pass are | 7/17/2025 |
Wiggins Pass area | 8/29/2025 |
FourStar® Bti CRG is a heavy, high-density and sand-based larvicide designed for both saltwater and freshwater habitats with vegetative canopy. A dual action-controlled release technology allows FourStar® Bti CRG to remain effective through wet and dry periods. It can kill larvae for up to 40 days and 4 floodings.
FEATURES:
High density, spherical silica sand carrier
10% Bti active ingredient
Dual-action controlled release technology
Up to 40 days residual
Effectiveness in intermittent flood areas
BENEFITS:
Can be applied to pre-flood areas
Wet/dry effectiveness reduces applications
Controls Aedes taeniorhynchus
Weight provides optimal vegetation penetration
Less target drift
More coverage per application
APPLICATION RATES
FourStar® Bti CRG is approved for ground and aerial application at a minimum 7.5 to 10 lbs./acre, up to 20 lbs./acre.
FourStar microbial larvicide kills mosquito larvae before they become adults by using the naturally occurring bacteria Bacillus sphaericus (Bsph) and Bacillus thuringiensis israelensis (Bti). These active ingredients are inherent in soil and contain protein crystals that when ingested rupture the gut wall of the larvae causing larval death.
To enhance performance, FourStar larvicides contain Central Life Sciences’ patented “Dual Action” release technology. This innovative technology regulates the release of active ingredients to the water surface as well as throughout the water column to ensure a long residual and maximum coverage.
Bacillus thuringiensis israelensis (Bti) is a biological larvicide used in Florida and throughout the United States to kill mosquito larvae in standing water but does not kill adult insects, other water insects like fish or beneficial insects, humans, or pets. Bti is a safe and effective tool for mosquito control, targeting only the larvae of specific insects such as mosquitoes, midges, and blackflies.
Resistance to Bacillus thuringiensis (Bt) has evolved in some insect populations, reducing the effectiveness of Bt crops and insecticides. This resistance stems from mutations in the insects' genes that alter Bt toxins' ability to bind to their midgut receptors. However, strategies such as using non-Bt refuges, planting Bt crops with multiple toxins, and continuing research into resistance mechanisms can help delay or mitigate the evolution of resistance, extending the usefulness of this technology.
Mosquitoes evolve resistance to Bacillus thuringiensis (Bt) through natural selection when exposed to the toxins, leading to the proliferation of resistant individuals in the population. This resistance involves genetic changes in mosquito populations, often affecting Bt toxin receptors in the midgut.
Resistance development is influenced by toxin complexity; combinations of Bt toxins, especially those including Cyt1Aa, significantly delay or prevent resistance, making them more effective for mosquito control than single-toxin formulations. Resistance can also be associated with epigenetic changes, such as alterations in DNA methylation and gene expression, which can modify an insect's immune and stress response.
Potential for indirect effects
While not directly toxic, Bti can impact dragonfly populations by disrupting their food web.
Reduced food source: Dragonfly nymphs are aquatic predators that primarily feed on other aquatic invertebrates, including mosquito and midge (chironomid) larvae. Since Bti treatments effectively reduce mosquito and midge populations, this can lead to a significant decrease in the available food for dragonfly nymphs.
Ecological concerns:
Trophic impact: A multi-year study in the Camargue region found a significantly lower abundance and richness of adult dragonflies in areas with regular Bti spraying compared to untreated areas. The researchers concluded that the Bti-induced scarcity of prey was a likely cause.
Reduced biodiversity: Research indicates that sustained Bti use may decrease the overall biomass and biodiversity of aquatic macrofauna, which could have cascading effects on the ecosystem and organisms like dragonflies.
Conclusion
Fourstar Bti CRG does not directly poison dragonflies. However, by eliminating the larvae of mosquitoes and other Diptera that serve as a primary food source, widespread or repeated Bti application can indirectly threaten dragonfly populations by causing a severe reduction in their prey.
Reference
However:
“While the gut of the dragonfly nymph may not produce the deadly conditions that the gut of the mosquito larvae does in the presence of Bti, that same toxin is being ingested by the dragonfly nymph when it feeds on the larvicide-exposed mosquito larvae as a food source. A further study is indicated before I can completely abandon that there is no relationship between the decline of the dragonfly presence at Madrona Marsh and the recent dosing of Bti.”
chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://csef.usc.edu/History/2014/Projects/J1732.pdf
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