What Is Azoxystrobin and Why Is It One of the Most Widely Used Fungicides Worldwide?

Technical Introduction

Azoxystrobin is a broad-spectrum systemic fungicide belonging to the strobilurin (QoI – Quinone outside Inhibitors) chemical class. It was the first strobilurin commercialized on a large scale and remains one of the most widely used fungicides globally.

Its mode of action is the inhibition of mitochondrial respiration by blocking electron transfer at the cytochrome bc1 complex (Complex III, Qo site). This disruption prevents ATP production in fungal cells, leading to energy starvation and death.

Azoxystrobin is unique among fungicides because it provides:

• Protective, curative, and eradicative action

• Systemic and translaminar activity, moving through xylem to protect new growth

• Long residual control, making it ideal for integrated crop protection programs

Applications

• Cereal Crops (Wheat, Barley, Oats, Maize):

  • Controls rusts, powdery mildew, Septoria leaf blotch, Helminthosporium leaf spots, Fusarium ear rot.

• Rice:

  • Highly effective against rice blast (Magnaporthe oryzae), sheath blight, and leaf spot.

• Soybeans:

  • Used against Asian soybean rust, Cercospora leaf blight, frogeye leaf spot.

• Fruits (Grapes, Bananas, Apples, Citrus, Berries):

  • Controls downy mildew, powdery mildew, anthracnose, scab, black sigatoka.

• Vegetables (Potatoes, Tomatoes, Cucumbers, Onions):

  • Effective against late blight, early blight, downy mildew, Alternaria leaf spot.

• Turf & Ornamentals:

  • Protects turfgrass from dollar spot, brown patch, rust, leaf spot, and anthracnose.

• Seed Treatment:

  • Combined with metalaxyl or fludioxonil for control of seed- and soil-borne pathogens.

Advantages

• Broad-Spectrum Activity: Effective against over 400 plant pathogenic fungi.

• Systemic & Translaminar: Moves within the plant for long-lasting protection.

• Flexible Use: Works in foliar sprays, seed treatments, and soil applications.

• Protective & Curative Action: Stops both new infections and early established disease.

• Yield & Quality Protection: Reduces disease-related stress, improving photosynthesis and crop vigor.

• Long Residual Control: Extended disease protection compared to older fungicides.

• Resistance Management Role: Often used in mixtures (with triazoles, SDHIs) to broaden spectrum and delay resistance.

Specifications (Typical Parameters)

FAQ

Q1: What crops benefit most from Azoxystrobin?
A: It is widely used in cereals, rice, soybeans, grapes, bananas, potatoes, and vegetables, making it one of the most versatile fungicides.

Q2: Is Azoxystrobin systemic?
A: Yes, it is systemic and translaminar, moving within the xylem to protect both treated and new plant tissues.

Q3: How does Azoxystrobin differ from triazole fungicides?
A: Triazoles (DMIs) inhibit ergosterol biosynthesis, while Azoxystrobin blocks mitochondrial respiration. They are often mixed to improve spectrum and resistance management.

Q4: Can Azoxystrobin control rice blast?
A: Yes, it is highly effective against rice blast, one of the most damaging rice diseases worldwide.

Q5: Is resistance an issue with Azoxystrobin?
A: Resistance has developed in some pathogens due to its single-site mode of action. For best results, it is applied in rotation or mixture with fungicides from different classes (e.g., triazoles, SDHIs).