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
- Myclobutanil (CAS 88671-89-0)
- Chemical class
- Triazole fungicide in the demethylation-inhibitor (DMI) group, which blocks sterol biosynthesis in fungal membranes.[3]
- Mode of action
- FRAC Group 3: DMI fungicides: C14-demethylase inhibitors in sterol biosynthesis[3]
- Signal word
- Spectracide Immunox Multi-Purpose Fungicide Spray Concentrate (base registration Chemsico Fungicide M): Caution[2]
How it works
Myclobutanil disrupts cellular processes in fungal cells and inhibits their growth.[1]
It is in FRAC Group 3, the DMI fungicides that inhibit sterol biosynthesis; the FRAC list rates the group medium risk for resistance, so alternate with fungicides from other groups.[3]
Timing
For best disease control the label calls for treatment every 2 weeks, starting when signs of disease first appear or, on lawns, when grass begins to green up in spring.[2]
Where it is used
The label lists outdoor use on roses, flowers, ornamental shrubs, trees, lawns, nuts and vegetables, for home use only.[2]
It prevents and cures listed diseases including brown patch, powdery mildew, black spot and rust, according to the label.[2]
Products and registrations
| Product | Registrant | EPA Reg. No. | Active % | Formulation | Signal word |
|---|---|---|---|---|---|
| Spectracide Immunox Multi-Purpose Fungicide Spray Concentrate (base registration Chemsico Fungicide M)[2] | United Industries Corp. (Spectrum Brands) | 9688-123 | 1.55% | liquid concentrate | Caution |
Label rates
| Product | Use | Pests | Rate |
|---|---|---|---|
| Spectracide Immunox Multi-Purpose Fungicide Spray Concentrate (base registration Chemsico Fungicide M) | Roses, flowers, ornamental shrubs and trees | Black spot, powdery mildew, rust and other listed diseases | 1.0 fl oz per gal of water[2] Spray to the point of runoff about every 2 weeks while disease conditions last (roses every 7–10 days); no more than 16 treatments per year. |
| Spectracide Immunox Multi-Purpose Fungicide Spray Concentrate (base registration Chemsico Fungicide M) | Lawns | Brown patch and other listed turf diseases | 3.5 fl oz per half-gallon of water per 250 sq ft[2] Start when grass greens up or at first signs of disease; every 2 weeks; no more than 16 treatments per year. |
| Spectracide Immunox Multi-Purpose Fungicide Spray Concentrate (base registration Chemsico Fungicide M) | Fruit trees (for example stone fruits and almond) | Blossom blight, brown rot, powdery mildew, rust, shothole | 0.5 fl oz per gal of water[2] Crop-specific limits apply, such as no more than 3 applications per season and no application within 90 days of harvest on almond. |
How to apply it, step by step
1. Protective gear
- The label lists no protective gear: it carries a CAUTION for moderate eye irritation, so keep it out of your eyes and off your clothing.[2]
- Wash your hands with soap and water promptly after use and after touching treated plants that day, and never use the measuring cups or spoons for food afterward.[2]
2. Before you spray
- It is for home use outdoors on roses, flowers, ornamental shrubs and trees, lawns, and the fruits, nuts and vegetables listed on the label.[2]
- It works best as a preventive or at the first sign of disease, so consider starting early in the season.[2]
- If the spray could reach house siding (vinyl especially), test a hidden spot and recheck it a few hours later; on an ornamental the label doesn't list, test a small area first.[2]
- Spray in calm weather when no rain is forecast for 24 hours, and keep it out of storm drains, ditches and gutters.[2]
3. Mixing
- In a pump-up or trigger sprayer, add the water first, then the concentrate, then close the sprayer and shake well; the label's conversions are ½ fl oz = 1 tablespoon and 1 fl oz = 2 tablespoons.[2]
- Roses, flowers, shrubs and trees: 1 fl oz per gallon of water (irises 2 fl oz; Douglas fir and loblolly and slash pine 3 fl oz).[2]
- Lawns: 3½ fl oz in half a gallon of water covers 250 sq ft (for crown rot, 3½ fl oz in a gallon).[2]
- Fruits and vegetables have their own rates on the label, for example ½ fl oz per gallon on most stone fruit, 2/3 fl oz on apples and 1 fl oz on tomatoes.[2]
4. Applying
- Spray ornamentals until the spray just begins to run off the leaves, about every 2 weeks while hot, moist weather favors disease; roses every 7 to 10 days if black spot is a problem.[2]
- Treat lawns from spring green-up or the first signs of disease, every 2 weeks for best control, and no more than 16 treatments a year.[2]
- If it rains before the spray has dried, spray again.[2]
5. After you spray
- Keep people and pets off treated plants until the spray has dried, and let it dry before you water.[2]
- Don't use treated lawn grass, clippings or ornamental plants for food or feed.[2]
- Days before harvest vary by crop: tomatoes, cucurbits, snap beans, strawberries, other berries and stone fruit can be treated up to the day of harvest; apples need 14 days and almonds 90.[2]
- Rinse the sprayer over the treated area so the rinse water doesn't run into drains.[2]
First aid
- 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, and call a poison control center or doctor; have the container with you.[2]
Storage, spills and disposal
- Store it in a cool, dry place away from heat or open flame.[2]
- Recycle an empty bottle if you can; 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 concentrate is a clear, light yellow solution with a mild odor, and the SDS uses the signal word Warning: it is suspected of damaging fertility or the unborn child and causes eye irritation.[4]
- Read all safety precautions before handling it, and wear protective gloves and eye protection.[4]
- If it gets in the eyes, flush them with plenty of water for 15 minutes, removing contact lenses, and get medical attention if irritation persists; after skin contact, wash with plenty of water.[4]
- If it is swallowed, don't induce vomiting unless medical personnel tell you to.[4]
- Keep the container tightly closed and store it locked up, out of reach of children.[4]
Safety and environmental hazards
People
The label signal word is CAUTION: it causes moderate eye irritation, so avoid contact with eyes or clothing and wash after handling.[2]
Pets
The label says not to let people or pets touch treated plants until the spray has dried, and not to use treated plants, grass or clippings for food or feed.[2]
Bees and pollinators
This home label carries no specific bee-toxicity statement; follow its general directions and avoid spraying open blooms where bees are working.[2]
Fish and water
The label says not to let the product enter or run off into storm drains, ditches, gutters or surface water, and to apply in calm weather when rain is not forecast for 24 hours.[2]
Common questions
- Is Spectracide Immunox the same as myclobutanil?
- Spectracide Immunox Multi-Purpose Fungicide Spray Concentrate contains 1.55% myclobutanil as its active ingredient and is registered under the Chemsico Fungicide M label.[2]
- How much Immunox per gallon for roses?
- One fluid ounce per gallon of water, sprayed to the point of runoff; the label suggests a 7- to 10-day schedule for roses.[2]
Sources
- University of California Statewide IPM Program, “Home and Landscape Pesticide Active Ingredients Database: myclobutanil.” ipm.ucanr.edu/home-and-landscape/pesticide-active-ingredients-database/active-ingredient-details/?uaiKey=36 (accessed 2026-10-06)
- U.S. EPA Pesticide Product Label System, “Chemsico Fungicide M (Spectracide Immunox) label, EPA Reg. No. 9688-123 (EPA-stamped, Sept. 10, 2010).” www3.epa.gov/pesticides/chem_search/ppls/009688-00123-20100910.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)
- Spectrum Brands (United Industries / Chemsico), “Spectracide Immunox Multi-Purpose Fungicide Spray Concentrate for Gardens Safety Data Sheet (Spectrum Brands, April 5, 2021; EPA Reg. No. 9688-123-8845, a distributor registration of the page's 9688-123 label; copy hosted on The Home Depot's product-document server).” images.thdstatic.com/catalog/pdfImages/1e/1e2c43b3-d419-4e62-aacc-524c6e69f1f1.pdf (accessed 2026-10-17)