The “Eldest Son” in Trizole Family-Propiconazole

Feb 24, 2023

Propiconazole is a yellow to brownish liquid. It is odorless and has a melting point of 122-124°C. Propiconazole is insoluble in water and slightly soluble in methanol, ethanol, and other organic solvents.

It belongs to the “first generation” class of triazoles, with specific five-membered three nitrogen–containing heterocyclic aromatic ring system. Propiconazole is used to control diseases such as brown spots, dollar spots, powdery mildew, and rust on a variety of turf grasses and ornamental plants. It is also used to control black mold and mildew of various fruits, vegetables, and ornamental crops.

The history of propiconazole

Propiconazole is a systemic fungicide first discovered in 1979 by Janssen Pharmaceutica. It was registered and used for the first time in the United States in 1992, and it is used to control various fungal diseases of rice, wheat, soybean, and other crops.

Propiconazole is a member of triazole fungicides, known for its effectiveness in controlling fungal diseases. Since its introduction, propiconazole has been widely used in agriculture and horticulture to control various fungal diseases, including rust, powdery mildew, and leaf spot. It is also used to treat fungal infections in animals, including dogs and horses.


Regulations regarding Propiconazole

Propiconazole is regulated in many countries due to its potential health and environmental risks. Taking the European Union as an example, the European Commission decided not to approve propiconazole in 2018, requiring member states to revoke the authorization of plant protection products containing this substance before June 19, 2019, and the grace period is until March 19, 2020.

In the UK, a fungicide mixture containing a combination of propiconazole, cycloconazole, and chlorothalonil failed the required risk assessment and was discontinued for sale and use in 2018.

In the United States, the Environmental Protection Agency (EPA) has determined that propiconazole tolerance residues in various crops and commodities, as well as registered products containing the substance, are subject to various labeling and use requirements.

How does Propiconazole work?

Propiconazole works by inhibiting the biosynthesis of ergosterol, an important component of fungal cell membranes. Ergosterol plays a key role in maintaining the integrity and fluidity of fungal cell membranes. By interfering with the production of ergosterol, propiconazole disrupts the normal structure and function of the fungal cell membrane, leading to the death of the fungus.

Propiconazole is a systemic fungicide, which means it is absorbed by the plant and transported to different parts of the plant, including leaves, stems, and roots. When plants are treated with propiconazole, the product is taken up by plant tissue and delivered to the vascular system throughout the plant, thereby providing protection against fungal infection in all parts of the plant.

The systemic properties of propiconazole make it an effective means of controlling the fungal diseases of plants. It can be used as a foliar spray or soil drench, and it can also be used as a seed treatment to prevent fungal infections in early plant growth.

Easy to formulate with other active ingredients

Propiconazole is known to be readily formulated with other active ingredients. This allows for the creation of various formulations that can target a variety of plant diseases.

Some popular combination includes:

Difenoconazole and propiconazole

Both Difenoconazole and propiconazole are triazoles. The mixtures, with more target sites, will be more effective compared with the propiconazole formulation alone.  This product is target on following diseases: Rice sheath blight, turf dollar spot, wheat sharp eyespot, scab, powdery mildew, rust, Banana leaf spot, etc.. Shall be applied before the onset of disease to achieve best results.

Propiconazole and Azoxystrobin

Triazoles in combination with strobilurin are highly effective, but also in an effort to combat Septoria resistance. The products are used to control maize leaf blight, sheath blight of rice, Pepper sore shin, Banana leaf spot, turf brown spot, powdery mildew, bacterial blight, etc.

Propiconazole and Isoprothiolane

Popular formulation to control rice blast.

Propiconazole and pyraclostrobin

This mixture is both protective and curative for Apple brown spots, flower brown spots, Banana leaf spots, etc.

Propiconazole now keeps its position on cash crops. With the pressure of generic competition as well as other newly developed triazole formulation products, the increasement in market share remains limited.

The benefits of propiconazole

Propiconazole offers several benefits to farmers, gardeners, and other users.

Here are some key benefits of propiconazole:

Control of Fungal Diseases

Propiconazole is effective against a variety of fungal diseases that damage crops, reduce yields and reduce the quality of produce. These diseases include rust, powdery mildew, and leaf spot, among others.

Systemic action

Propiconazole is systemic, which means it can be taken up by the plant and transported to various parts of the plant, thereby preventing fungal infection in leaves, stems, and roots.


Propiconazole can be used on a variety of crops, including cereals, fruits, vegetables, and ornamentals. It can be used as a foliar spray, soil water, or seed treatment, offering flexibility and convenience to farmers and gardeners.


Propiconazole is generally safe for humans and the environment when used according to label directions. It has low toxicity and poses no significant risk to non-target organisms.

Resistance management

propiconazole is a triazole fungicide, which has been proven to be effective in controlling resistance to other fungicides. Its use can help reduce the likelihood that fungal populations will develop resistance to other fungicides, thereby maintaining their efficacy over time.

Other Applications of Propiconazole

Propiconazole is a commonly used agricultural fungicide and has become widely utilized for wood protection as well. Its antiseptic qualities make it a popular choice for coating or application; countries with large areas of pine and spruce plantations such as Austria, Belgium, Denmark, France, Finland, Germany, Switzerland, Norway, and the Netherlands have all seen an uptick in propiconazole-based wood preservation.


To wrap things up

Despite regulatory pressure in recent years, propiconazole has maintained its status as a cash crop and is also popular for wood protection. However, it is important to follow regulatory guidelines and safety precautions when using propiconazole to minimize potential health and environmental risks.