The label is the law. Read your product's label before you mix or apply; the rates here come from the labels listed under Sources.
- Active ingredient
- Sulfur (elemental) (CAS 7704-34-9)
- Chemical class
- Inorganic multi-site contact fungicide that also controls mites and some insects.[1][3]
- Mode of action
- FRAC Group M02: Multi-site contact activity: inorganic (sulfur)[3]
- Signal word
- Bonide Sulfur Plant Fungicide Micronized Spray or Dust: Caution[2]
How it works
Sulfur kills fungi on contact; the main theory is that it enters fungal cells and disrupts their respiration, and insects that touch or eat it lose the ability to produce energy normally.[1]
Because it is preventive, the label says to time sprays before rainy periods or spore release, starting before disease appears on many crops.[2]
Other labeled uses
For chiggers in yards, the label calls for about 2 pounds of dust per 1,000 square feet a day or two before you need protection, repeated weekly.[2]
As a soil acidifier, 1 to 1¼ pounds in 50 gallons of water lowers the pH of 100 square feet by about one unit; do not try to change pH by more than one unit a year.[2]
Where it is used
Do not dust or spray sulfur in hot weather, do not use it within 2 weeks of an oil spray, and on citrus wait 3 weeks after an oil spray.[2]
Some varieties are injured by sulfur: McIntosh, Golden Delicious and Jonathan apples, Anjou and Comice pears, and Concord and other labrusca grapes.[2]
Sulfur dust in the air ignites easily, so keep flames and sparks away and do not smoke while dusting; stay out of treated areas for 24 hours unless wearing long sleeves, long pants, shoes and socks.[2]
Products and registrations
| Product | Registrant | EPA Reg. No. | Active % | Formulation | Signal word |
|---|---|---|---|---|---|
| Bonide Sulfur Plant Fungicide Micronized Spray or Dust[2] | Bonide Products, LLC | 4-62 | 90.0% | wettable dust | Caution |
Label rates
| Product | Use | Pests | Rate |
|---|---|---|---|
| Bonide Sulfur Plant Fungicide Micronized Spray or Dust | Fruit trees, berries, grapes, beans, peas and strawberries | Powdery mildew, rust, scab, brown rot, leaf spot and spider mites | 1–3 tbsp per gal of water[2] The rate depends on the crop (for example apples 1–2½ rounded Tbsp, beans and peas 1½–3 level Tbsp, strawberries 1–2 level Tbsp). Most crops can be sprayed up to the day of harvest. |
| Bonide Sulfur Plant Fungicide Micronized Spray or Dust | Roses, ornamental shrubs and perennials (not in California) | Black spot, rust, powdery mildew, spider mites | 2–2.25 tbsp per gal of water[2] Begin when disease appears; repeat every 5 to 10 days and after rain. |
How to apply it, step by step
1. Protective gear
- The label lists no specific gear, but it is harmful if swallowed, inhaled or absorbed through the skin and can irritate eyes, nose, throat and skin: avoid breathing the dust or spray mist and keep it off your skin and out of your eyes.[2]
- Wash with soap and water after handling, and wash contaminated clothing before wearing it again.[2]
2. Before you spray
- It is for home gardens, ornamentals, lawns and grounds, not plants grown for sale.[2]
- Don't spray or dust during hot weather, within 2 weeks of an oil spray, or on citrus within 3 weeks of an oil spray.[2]
- Sulfur can injure some varieties: the label names McIntosh, Golden Delicious and Jonathan apples, Anjou and Comice pears, and Concord-type grapes.[2]
- Sulfur dust in the air ignites easily: when dusting, keep fire and sparks away from the duster and the dust cloud, and don't smoke.[2]
- It is toxic to fish: use it in calm weather when no rain is forecast for 24 hours, not when it would drift, and keep it out of drains and gutters.[2]
3. Mixing
- It can go on as a dust or mixed with water as a spray; rates are in tablespoons per gallon and differ by plant.[2]
- Roses, ornamental shrubs and perennials: 2 to 2¼ level tablespoons per gallon of water (not for this use in California).[2]
- Vegetables and fruit, for example: beans and peas 1½ to 3 level tablespoons; strawberries 1 to 2 level; grapes 1 to 3 level; apples 1 to 2½ rounded; peaches and nectarines 1 to 3 rounded.[2]
4. Applying
- Spray with a good pressure sprayer, covering all leaf surfaces thoroughly; when dusting, apply a thin, even film to all leaf surfaces and fruit.[2]
- Apply before rainy periods, when fungal spores are released; it protects rather than cures.[2]
- On roses and ornamentals, begin when disease appears and repeat every 5 to 10 days and after rain; on beans and peas, every 7 to 10 days; on cane berries, currants and gooseberries, about every 10 days.[2]
5. After you spray
- Don't go into treated areas for 24 hours without a long-sleeved shirt, long pants, and shoes plus socks.[2]
- On the fruits and vegetables listed, it may be used up to the day of harvest.[2]
First aid
- If swallowed, call a poison control center or doctor right away, have the person sip a glass of water if they can swallow, and don't induce vomiting unless told to.[2]
- If inhaled, move the person to fresh air and call 911 if they aren't breathing; on skin or clothing, take off contaminated clothing and rinse with plenty of water for 15 to 20 minutes.[2]
- In the eyes, hold them open and rinse slowly and gently with water for 15 to 20 minutes, removing contact lenses after the first 5 minutes; the label also lists the National Pesticide Information Center, 1-800-858-7378.[2]
Storage, spills and disposal
- Store and carry it upright, in a cool, dry place children and pets can't reach.[2]
- Put an empty container in the trash or recycling; for a partly full one, call your local solid waste agency, and never pour product down a drain.[2]
From the safety data sheet
- The SDS uses the signal word Warning: the dust may be harmful if swallowed, may cause mild skin irritation, causes eye irritation and may irritate the airways. People allergic to sulfa drugs may also react to elemental sulfur.[4]
- Sulfur dust is highly flammable: dust suspended in the air can ignite from friction, static, heat, sparks or flame, and dust clouds can explode, so keep it away from heat, sparks and open flames.[4]
- If it gets in the eyes, flush them with plenty of water for 15 minutes while holding the lids apart (don't rinse with boric acid) and get medical attention for severe irritation; wash skin with plenty of soap and water and wash clothing before reuse.[4]
- If someone breathes in the dust, get them to fresh air, keep them warm and quiet, watch for an allergic reaction and seek medical attention.[4]
- Sweep or shovel up spills gently with a natural-fiber broom to avoid raising a dust cloud, then wash the spot; store it tightly closed in a cool, dry, well-ventilated place away from heat, flames and oxidizers such as chlorates and nitrates.[4]
Safety and environmental hazards
People
The label signal word is CAUTION: harmful if swallowed, inhaled or absorbed through the skin, and it may irritate the eyes, nose, throat and skin. Sulfur is low in toxicity to people, and EPA concluded there are no known cancer risks from it; breathing the dust over the long term may irritate the airways.[2][1]
Pets
The label says to store it out of reach of children and pets. Animals that eat too much sulfur can be poisoned, with stomach, lung and neurological effects that can be fatal.[2][1]
Bees and pollinators
NPIC reports sulfur is practically non-toxic to the honeybee.[1]
Fish and water
The label states it is toxic to fish, although NPIC reports it practically non-toxic to bluegill, rainbow trout, water fleas and mysid shrimp in testing; keep it out of drains and surface water either way.[2][1]
Common questions
- How much sulfur fungicide per gallon?
- From 1 to 3 tablespoons per gallon depending on the plant; for roses, shrubs and perennials, 2 to 2¼ level tablespoons.[2]
- Can I spray sulfur after horticultural oil?
- Wait at least 2 weeks after an oil spray, or 3 weeks on citrus.[2]
- Can I use sulfur on all grapes?
- No. The label warns that Concord and other labrusca-type grapes may be injured.[2]
- Is sulfur safe for bees?
- NPIC reports it is practically non-toxic to honeybees.[1]
Sources
- National Pesticide Information Center, “Sulfur General Fact Sheet.” npic.orst.edu/factsheets/sulfurgen.html (accessed 2026-10-06)
- U.S. EPA Pesticide Product Label System, “Bonide Sulfur Plant Fungicide Micronized Spray or Dust label, EPA Reg. No. 4-62 (EPA-stamped, Apr. 1, 2021).” www3.epa.gov/pesticides/chem_search/ppls/000004-00062-20210401.pdf (accessed 2026-10-06)
- Fungicide Resistance Action Committee, “FRAC Code List 2025.” www.frac.info/media/ljsi3qrv/frac-code-list-2025.pdf (accessed 2026-10-06)
- Bonide Products, LLC, “Bonide Sulfur Plant Fungicide Safety Data Sheet (Bonide Products, revised September 1, 2021; product code 462, the product registered as EPA Reg. No. 4-62, the page's product).” cdn.shopify.com/s/files/1/0533/3847/2647/files/BND141_MSDS.pdf (accessed 2026-10-19)