Ethephon and Gibberellic Acid: Plant Growth Regulator Guide

Plant growth regulators change how a crop grows, ripens or sets fruit rather than controlling a pest, weed or disease. Ethephon and gibberellic acid are two of the most widely traded, and they often appear side by side in a regulator price list. They act through different plant hormones, are used for different purposes, and are dosed in different ways, so buying them well starts with the crop and the result the grower wants.

Averstar's catalogue lists ethephon 480 g/L SL and 40% SL and gibberellic acid in tablet form. This guide explains what each regulator does, how their products are expressed and packed, and which documents to request. The approved destination-market label always decides the permitted crops, timing, concentration and restrictions for the product actually supplied.

Quick answer: Use ethephon where the label calls for ethylene effects such as ripening or shortening straw, and gibberellic acid where it calls for gibberellin effects such as fruit set or berry size. Follow the label's crop stage and concentration exactly, because the wrong timing or rate can damage the crop.

What ethephon does

The University of Hertfordshire Pesticide Properties Database (PPDB) entry for ethephon describes a systemic plant growth regulator that releases ethylene, a natural plant hormone, inside plant tissue. Its uses include preventing lodging in cereals and promoting pre-harvest ripening of fruit, with example applications in cereals, pineapples, bush fruit, coffee, tobacco, rubber and ornamentals. The PPDB notes it is often supplied as a liquid concentrate for dilution and foliar spraying.

Ethylene effects depend strongly on crop stage, temperature and concentration, which is why labels tie each use to a specific stage and rate. The concentrate itself is strongly acidic: confirm that the containers, closures and any metal parts in packaging are acid-resistant, and keep the safety data sheet aligned with the destination-market label.

What gibberellic acid does

The University of Hertfordshire Bio-Pesticides Database (BPDB) entry for gibberellic acid describes a plant growth regulator used to improve fruit set, increase berry size and control fruit maturity, with example uses in tree fruit, soft fruit including grapes, and hops. It promotes stem elongation by stimulating cell division and elongation, and it is produced commercially by fermentation. The BPDB lists granules, water-soluble tablets, soluble powders and soluble crystals as available formulations.

Gibberellic acid is usually applied at very low concentrations in the spray solution, and labels state those concentrations for each crop and stage. Tablets carry a fixed amount of active, which makes it easier to prepare a labelled spray concentration without weighing small quantities of powder.

Compare the catalogue formulations

• Ethephon 480 g/L SL and Ethephon 40% SL: soluble concentrates. A value of 480 g/L is grams per litre, while 40% may be by weight or by volume, so the two are different products unless the unit and density match. Use only the rate on the registered product's label.
• Gibberellic acid 10% tablet: water-soluble tablets. Confirm the active content per tablet as well as the percentage, because spray concentrations are calculated from the amount of active per tablet. Tablets should be kept dry and sealed until use.

Penn State Extension's overview of pesticide formulations explains how soluble liquids and solid formulations are handled. For quality checks, ask for the certificate of analysis together with solution stability for SL products and dissolution or disintegration results for tablets, as described in FAO/WHO pesticide specifications.

Technical material is not an end-use product

Technical material (TC) is the concentrated active ingredient that formulators use to make end-use products. It is registered and traded separately, with its own specification and documents, and it is not sold to growers for direct application. When a quotation lists gibberellic acid TC, confirm the purity specification and that the buyer holds the registration or formulation licence that covers it.

A product selection checklist

• The crop, the intended effect (for example ripening, fruit set or berry size) and the crop stage on the label.
• Ethephon or gibberellic acid, according to the hormone effect the label describes.
• Concentration and unit (g/L, % or active per tablet) matched on quotation, certificate and label.
• Acid-resistant packaging for ethephon; dry, sealed packaging for tablets.
• For technical material: the purity specification and the buyer's registration or licence.
• Safety data sheet and translated label artwork for the destination market.

Build the inquiry around the intended use

Send the crop, the intended effect, the preferred product and concentration, the packaging and the destination market through our contact form. For a first order, a pesticide sample evaluation plan helps compare samples against the agreed specification before scaling up.