Everything You Need to Know About Rust in Maize: Symptoms and Solutions

This blog provides information on rust disease in maize, its damage symptoms, favourable factors , and effective strategies to control and prevent it.

What is Rust in Maize?

Rust disease in maize is caused by fungi belonging to the genus Puccinia. Rusts are common fungal pathogens that can infect various plants, including cereals like maize (corn). The rust disease affecting maize is commonly known as maize rust or corn rust. Common rust produces rust-colored to dark brown, elongated pustules on both leaf surfaces. The pustules contain rust spores (urediniospores) that are cinnamon brown in color. Pustules darken as they age. Leaves, as well as sheaths, can be infected.

Overview of Rust Disease in Maize

Common Name	Rust
Scientific Name	Puccinia sorghi
Category of plant disease	Fungal disease
Mode of Spread	Wind borne spores, Alternate host
Affected parts of the plant	Leaves
Type of Infestation	Disease

Favorable factors for Rust disease in Maize:

• Warm temperatures (18-27°C): Rust fungi flourish in warm weather, with optimal temperatures for their growth and sporulation ranging from 18 to 27°C.

• High humidity (above 70%): Fungal spores require moisture to germinate and penetrate plant tissues.

Initial Symptoms of Rust in Maize:

• Tiny, pinpoint-sized pustules: These appear on both sides of the leaves, initially scattered but eventually forming clusters or bands
• Polysora Rust: Reddish-brown, circular
• Common Rust: Cinnamon-brown
• Brown Stripe Rust: Elongated brown streaks on the upper leaf surface, yellowing on the lower surface
• Slight yellowing around pustules: The area surrounding the pustules may exhibit light yellowing.
• Stunted growth: The plant may show slight stunting compared to healthy plants.

Severe Symptoms of Rust in Maize:

• Enlarged pustules and coalescing lesions: Pustules grow larger and may merge, forming extensive patches or bands of raised, discolored tissue.
• Significant leaf yellowing and defoliation: Infected leaves turn yellow, wilt, and eventually die off prematurely, leading to significant defoliation.
• Stunted plant development: Severely affected plants show significant stunting, impacting tassel development and overall plant health.

Control measures for Rust in maize:

Cultural control of Rust disease in Maize

• Remove the alternate hosts .
• Collect the remains of the crop and destroy by burning or burying

Chemical control of Rust disease in Maize

Use following Fungicides for the control of Rust in Maize

Product	Technical Name	Dosage
SAMARTHA	Carbendazim 12 % + Mancozeb 63 % WP	Use 300-400 grams per acre
Azodharma	Azoxystrobin 18.2 % + difenoconazole 11.4 % SC	150-200 ml per Acre
TYSON		Dissolve 3G of Katyayani Trichoderma Viride in one litre of water and spray on both sides of leaf during evening hours

FAQs related to Rust disease in Maize

Q. What is the cause of Rust in Maize ?

A. Maize rust, caused by Puccinia sorghi, grows in cool, moist weather between 15 to 25°C. It spreads first through other plants and then by wind carrying spores.

Q. How do you control rust in Maize?

A. To control rust in maize, use suitable fungicides like Carbendazim 12 % + Mancozeb 63 % WP, Azoxystrobin 18.2 % + difenoconazole 11.4 % SC according to recommended guidelines.

Q. Is Maize Rust a fungal disease?

A. Yes, maize rust is a fungal disease caused by fungus Puccinia sorghi. It affects maize crops by forming pustules on leaves, stalks, and ears.

Q. What are the symptoms of Rust in Maize ?

A. Rust on maize starts as tiny spots on the leaves. These spots turn into cinnamon-brown, powdery bumps that can be round or stretched.