Home and Landscape: Pesticide Active Ingredients Database

chlorothalonil

Pesticide Type

Fungicide

See the Pesticide Terms page for definitions of terms used in this database.

How Does This Active Ingredient Work?

This active ingredient is a broad-spectrum, protectant fungicide. Chlorothalonil inhibits fungal growth on plant leaves.

Potential Hazards1

Water quality2
(aquatic wildlife)Footnote 1. Water quality ratings from Pesticide Choice: Best Management Practice (BMP) for Protecting Surface Water Quality in Agriculture, ANR Publication 8161, or the USDA-NRCS WIN-PST database—see Pesticides: Water-Related Toxicology of Active Ingredients. Information to be added.
Natural enemies3
(beneficials) Information to be added.
Honey bees4Footnote 3.Honey bee ratings are: (Very High) I-Do not apply to blooming plants; (High) II-Apply only during late evening; (Moderate) III-Apply only during late evening, night, or early morning; and (Low) IV-Apply at any time with reasonable safety to bees. For more information, see How to Reduce Bee Poisoning From Pesticides (PDF), Pacific Northwest Extension Publication PNW591. Information to be added. Acute toxicity to people and other animals5Footnote 4.Acute oral toxicity ratings for people and other mammals based on LD50 and US EPA Acute Toxicity Ratings system: H = Highly Toxic (LD50 < 50), M = Moderately Toxic (LD50: 50-500), L = Slightly Toxic (LD50: 500-5000), VL = Not Acutely Toxic (LD50 > 5000). Information to be added.
LVL
For potential long-term consequences of the active ingredient, see the California Prop 65 list for materials known to cause cancer or reproductive toxicity, or the U.S. Environmental Protection Agency list of materials that can cause cancer or organ damage.
Hazards Ratings: VL=Very low, L=Low, LM=Low to Moderate, M=Moderate, LH=Low to High, MH=Moderate to High, H=High, VH=Very High, N=None, NKR=No Known Risk, — = No data
Honey Bee Ratings:
Do not apply or allow to drift to plants that are flowering including weeds. Do not allow pesticide to contaminate water accessible to bees including puddles.
Do not apply or allow to drift to plants that are flowering including weeds, except when the application is made between sunset and midnight if allowed by the pesticide label and regulations. Do not allow pesticide to contaminate water accessible to bees including puddles.
No bee precaution, except when required by the pesticide label or regulations.

Safety Precautions

Read the product label for specific information on personal protective equipment (PPE) and safety requirements. Note that many consumer pesticide products do not include information about PPE on the label. You should still wear basic PPE to protect yourself from exposure, such as chemical resistant gloves, long sleeves, and goggles. Learn about safe use and disposal of pesticides.

Warning on the use of pesticides.

Pest Notes and Example Products

These products were registered for home and garden use in California in July 2013. Professional use products are not included. If no example products are listed, this active ingredient may be available only for professional use. Individual products are registered for specific uses on specific sites. Read the label to determine if the product is registered for your use. Note that some products may be formulated with additional pesticides. Information to be added

This active ingredient is mentioned in the following Pest Notes:

Example home, garden or landscape use products6:

    Bonide Fung-Onil, Gardentech Daconil Fungicide

Example professional use products:

    Concert II, Daconil Action, Enclave, Instrata, Renown Fungicide, Spectro 90

Footnotes

1 Potential hazard ratings may vary depending on the species, environmental conditions, application rate and type, and pesticide formulation; ratings may not be available for all active ingredients due to these factors. Toxicities are averages of reported effects and should only be used as a general guide.
2 Water quality ratings are from the USDA-NRCS WIN-PST database—see Pesticides: Water—Related Toxicology of Active Ingredients. This information is not currently available.
3 Impact on natural enemies ratings are from the UC IPM Pest Management Guidelines for Agriculture database.
4 Honey bee ratings are from the UC IPM Bee Precaution Pesticide Ratings.
5 Acute oral toxicity ratings for people and other mammals based on LD50 and US EPA Acute Toxicity Ratings system: H = Highly Toxic (LD50 < 50), M = Moderately Toxic (LD50: 50-500), L = Slightly Toxic (LD50: 500-5000), VL = Not Acutely Toxic (LD50 > 5000).
6 Example consumer and professional products are derived from the California Department of Pesticide Regulation database and annual retail shelf survey by the UC Office of Pesticide Information and Coordination. No endorsements of named products are intended, nor is criticism implied of products not mentioned.