The label is the law. Rates and restrictions below are taken from the product labels listed under Sources. Your product's own label governs; read it before you mix or apply. Mixing calculator · Disclaimer
- Active ingredient
- Extract of Reynoutria sachalinensis (giant knotweed)
- Chemical class
- Plant extract made with ethanol, containing anthraquinones and resveratrol. FRAC lists it under host plant defence induction as an anthraquinone elicitor, Group P05.[2]
- Mode of action
- FRAC Group P05: Host plant defence induction: anthraquinone elicitors (plant extract)[2][1]
- Signal word
- Regalia Bioprotectant Concentrate home and garden sublabel (also sold as Regalia Home & Garden or Regalia Garden Biofungicide): Caution[1]
How a plant-defense fungicide works
The label says the extract boosts phenolics and antioxidants in the plant and strengthens cell walls. That defense response starts within one to two days of spraying.[1]
The protection is not systemic, so only covered leaves benefit and new growth needs fresh sprays. Use it as a preventive, before symptoms build.[1]
Cautions from the label
Don't apply it within 14 days of a sulfur fungicide during hot weather. Use only hand-held pressurized sprayers, trigger bottles or hose-end sprayers on the home label.[1]
Where it is used
Shake the concentrate, mix 2 tablespoons per gallon, and spray tops and bottoms of leaves until they drip. Don't let the mixed spray sit overnight.[1]
Start before disease shows or at the first sign, then repeat about every 7 days. As a preventive, every 7 to 14 days is enough until disease risk passes.[1]
For transplants, dip the roots briefly in the same mix, or drench the soil around new plants. Drenches can be repeated every 10 to 14 days.[1]
It can go on up to and including the day of harvest for fruits and vegetables. Test a few leaves first and check them after 2 to 4 days for burning.[1]
Products and registrations
| Product | Registrant | EPA Reg. No. | Active % | Formulation | Signal word |
|---|---|---|---|---|---|
| Regalia Bioprotectant Concentrate home and garden sublabel (also sold as Regalia Home & Garden or Regalia Garden Biofungicide)[1] | Pro Farm Group, Inc. | 84059-3 | 5.0% | liquid concentrate (plant extract) | Caution |
Label rates
| Product | Use | Pests | Rate |
|---|---|---|---|
| Regalia Bioprotectant Concentrate home and garden sublabel (also sold as Regalia Home & Garden or Regalia Garden Biofungicide) | Home vegetables, fruits, nuts, roses, flowers, bedding plants, houseplants, trees and shrubs | Powdery mildew, black spot of rose, rust, leaf spots, gray mold, anthracnose, downy mildew, early and late blight, bacterial spot and speck, fire blight | 1 fl oz product per gallon of water[1] That's 2 tablespoons per gallon, or 1½ teaspoons in a 32 oz trigger bottle. The same mix is used for sprays, pre-plant root dips and soil drenches. |
Safety and environmental hazards
People
Signal word CAUTION: causes moderate eye irritation. Avoid contact with eyes, skin and clothing, and wash with soap and water after handling.[1]
Pets
The hazard statement for people and domestic animals is moderate eye irritation. The home label has no separate pet re-entry instruction.[1]
Bees and pollinators
The label carries no bee or pollinator warning.[1]
Fish and water
Keep it out of storm drains, ditches, gutters and surface water. Spraying in calm weather with no rain expected for 24 hours keeps it on target.[1]
Common questions
- How much Regalia per gallon of water?
- One fluid ounce, which is 2 tablespoons, per gallon. In a 32 oz spray bottle, use 1½ teaspoons.[1]
- Can Regalia be used in an organic garden?
- The home and garden sublabel carries the statement that it can be used in organic gardening.[1]
- Will Regalia cure a plant that is already badly infected?
- It works best as a preventive. For disease already present, the label's schedule is a spray every 7 days until symptoms are gone, then every 14 days.[1]
Sources
- U.S. EPA Pesticide Product Label System, “Regalia Bioprotectant Concentrate master label label, EPA Reg. No. 84059-3 (EPA-stamped, Aug. 20, 2026).” www3.epa.gov/pesticides/chem_search/ppls/084059-00003-20260820.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)