The Maize Rust Disease is a fungal disease of maize caused by species in the Puccinia genus and is also known as common corn rust. This disease affects the leaves, stems, and husks of maize or corn and can cause significant yield losses. Maize rust is a widespread and economically important disease with the potential to cause significant damage to maize crops.
To effectively manage this disease, it is important to understand its disease cycle, the mode of disease spread, and the best methods for controlling it. This article will provide an overview and discussion of the Maize Rust Disease in Maize crops, including its symptoms, identification techniques, and control.
Maize Rust Disease Management
The Causal Organism of Maize Rust Disease
- Puccinia sorghi is an obligate parasite that belongs to the Family Pucciniaceae, Order Pucciniales of the Phylum Basidiomycota.
- It lives as a hemibiotroph, initially as a biotroph, and then changes to a necrotroph in the later stages of the disease.
- The fungus survives as tiny, reddish-brown pustules on the leaves of maize plants.
The Disease Cycle of Maize Rust Disease
The disease cycle begins with the primary infection by uredospores, which occurs during the growing season when the wind spreads the fungus spores from infected plants. These spores settle on the leaves, where they germinate and penetrate the epidermal cells of the leaves. Once inside the cells, the fungus reproduces, releasing more spores into the air.
The next stage of the disease cycle is the spread of the disease. During this stage, the fungus can spread to other parts of the maize plant and nearby maize plants. The fungus can spread through wind, rain, and contact with other infected plants. The third stage of the cycle is the formation of rust pustules. In this stage, the fungus produces small reddish-brown lesions on the leaves and other plant parts. These lesions contain spores that can be spread to other plants, leading to more infection.
The fourth stage is the production of fungal spores. During this stage, the fungus produces large spores that can be spread to other plants. The wind currents carry these spores to other maize plants. The final stage of the disease cycle is secondary infection. The fungus infects the maize plant’s kernels and cob during this stage. This can lead to significant yield losses, as the kernels and cob are the economical parts harvested for food.
Occurrence of Maize Rust Disease in Maize Crop
- Location of Maize Rust disease: This disease occurs in maize crops in Africa, India, Bangladesh, the USA, Mexico, Argentina, Brazil, Thailand, Spain, Italy, and France.
- Host range: The most common crops affected by rust are maize, sorghum, pearl millet, finger millet, rice, wheat, and sugarcane.
Favorable Conditions for Maize Rust Disease Spread in the Field
- The optimum conditions for maize rust development are cool temperatures of 10-15°C and high relative humidity of 90%.
- High humidity and prolonged periods of leaf wetness by rain or dew can also increase the risk of infection.
- Poor soil fertility can also create favorable conditions for maize rust disease spread.
- The optimum temperature required for the germination of conidia is 10-12°C.
Damage Symptoms of Maize Rust Disease
- Maize rust can be identified by its characteristic reddish-brown lesions on the leaves, which can sometimes dry and appear as a powdery substance.
- The infection results in yellowish-orange pustules on the leaves on both sides and husks, which can cause the plant to become stunted and deformed.
- Infected plants typically show yellowish-brown leaf lesions, which can eventually be covered in reddish-brown pustules. The leaves may also become distorted and curl up.
- As the disease progresses, the pustules turn black since black teliospores will replace the red uredospores.
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