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Mandolin

AMVAC · 1-Naphthaleneacetic Acid, Potassium Salt 24.2% · EPA Reg 5481-628 · Plant Growth Regulator Document last checked 2026-05-30

About this product

Active ingredient 1-Naphthaleneacetic Acid, Potassium Salt 24.2%
Manufacturer AMVAC
Category Plant Growth Regulator

Full details for Mandolin

Source product label ↗ Open the catalog source label while the local copy is reviewed. Verify the product name, EPA registration number, and revision before use. Source safety data sheet ↗ Open the catalog source SDS while the local copy is reviewed. Verify the exact product and revision before relying on it. EPA registration data Reg. 5481-628 — registry reference, signal word and status.

Applicator discussion

Nothing here is label direction — the label is the law. These are notes from other applicators, moderated before they appear. Check the labeling accompanying the product and applicable state requirements.

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According to the label From the product label

These details were extracted from this product's label PDF. The label is the law. Confirm every rate, site, restriction and safety requirement against the label before mixing or applying. Check for a state supplemental label; a product may be restricted or prohibited in a state or site even when a rate appears below. · EPA registration data for Reg. 5481-628 →

Mandolin is a plant growth regulator used for thinning citrus crops. Its active ingredient is 1-Naphthaleneacetic Acid, Potassium Salt (24.2%), which is equivalent to 20.2% 1-Naphthaleneacetic Acid (NAA) per gallon. The product is designed to thin fruit during a heavy crop year to provide adequate return bloom in the following season. It can be applied to mandarins (tangerines, tangelos, and clementines) and oranges. Application rates vary based on the target concentration of NAA (ppm) and the spray volume used (150, 200, 250, or 300 gallons per acre). For mandarins, the product is applied to the entire fruiting area during the early stage of development (5 to 20 mm in diameter) during the normal 'June Drop' period. For oranges, it is applied during the early stage of development (5 to 20 mm in diameter) during the normal 'June drop' in Florida. Users should note that higher thinning activity may occur during hot and dry conditions, particularly when temperatures exceed 85°F. When handling, use long-sleeved shirts, long pants, shoes plus socks, chemical-resistant gloves, and protective eyewear. Avoid contact with skin and eyes, as it causes moderate irritation. Always follow local extension specialist advice for specific timing and application methods, especially regarding wind speed and spray drift management.

Pests covered (1)
Scale Insects
Areas treatable (1)
Citrus (Mandarins and Oranges)

How to treat each type of area 1

Citrus (Mandarins and Oranges)

Location Rate Unit Dilution Label notes
Outdoor Varies by concentration fl. oz./acre 150-300 GPA Used for fruit thinning during heavy crop years to ensure adequate return bloom.

Mixing instructions 2

For pests Amount Per Finished strength Label notes
Mandarins 17.5-52.6 fl. oz./acre 200-300 ppm NAA Spray volumes of 150, 200, 250, or 300 GPA.
Oranges 6-24 fl. oz./100 gallons 100-500 ppm NAA Apply at 100 to 500 ppm.

Worker safety

Re-entry interval (REI) 48
PPE required Long-sleeved shirt and long pants, shoes plus socks, chemical-resistant gloves (except for pilots), and protective eyewear.

Timing & weather

Use restrictions 5