Daconil WeatherStik Fungicide is a broad-spectrum contact fungicide formulated for the preventive control of fungal and algal diseases in turfgrass and ornamental plants. The active ingredient is chlorothalonil, a multi-site inhibitor classified under FRAC Group M5, which provides a foundational mode of action for resistance management.
Product Configuration and Specifications
The product is defined by its active ingredient, formulation technology, and commercial packaging. The active ingredient is chlorothalonil. It is formulated as a flowable suspension concentrate with a built-in surfactant system. The standard commercial unit is a 2.5-gallon container. These containers are packaged 2 per case, with 72 cases (144 containers) comprising a standard pallet.
Functional Mechanism and Design
Chlorothalonil acts as a multi-site contact fungicide. It inhibits several enzymatic processes within fungal cells, including glycolysis and respiration, leading to a loss of cellular integrity. The "WeatherStik" technology incorporates a proprietary surfactant that enhances the adherence of the fungicide to plant surfaces, providing superior rainfastness and extended residual activity. The fungicide forms a protective barrier on the plant surface and does not exhibit systemic movement within the plant.
Target Applications and Performance
The product is labeled for use on turfgrass and over 75 ornamental plant species. It controls a broad spectrum of diseases including dollar spot, brown patch, gray leaf spot, algae, anthracnose, rust, and snow molds. Performance is characterized by providing preventive control for 14 to 21 days per application. Its multi-site activity makes it a key component in fungicide rotation programs to delay the development of pathogen resistance to single-site fungicides.
Application Specifications and Protocol
The product is applied as a foliar spray in sufficient water volume to ensure thorough, uniform coverage of all plant surfaces.
Standard Application Protocol:
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Mixing: The flowable formulation mixes readily with water. The built-in surfactant eliminates the need for additional spray adjuvants in most situations. The spray solution remains in suspension for up to six hours under continuous agitation.
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Coverage: Complete coverage is critical for efficacy, as the product is not systemic. Spray applications must target the crown and sheath area of turfgrass for optimal protection.
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Timing: Apply preventatively at the first sign of disease pressure or according to a scheduled preventive program. The product is rainfast soon after application.
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Tank Mixing: It is commonly tank-mixed with systemic fungicides like azoxystrobin or propiconazole for broad-spectrum control with both contact and systemic activity.
Handling and Safety
Chlorothalonil requires careful handling. Applicators must wear appropriate personal protective equipment including long sleeves, long pants, chemical-resistant gloves, and eye protection. Avoid contact with skin, eyes, and clothing. Do not apply to plants under stress. Observe all re-entry intervals specified on the product label. Store in a secure, dry location away from foodstuffs and out of reach of children.
