Maize (Zea mays) is one of the important staple crops in the world, providing food, feed, and fuel for millions of people. It’s widely grown in tropical and subtropical regions and is known for its high yield potential and versatility. Bacterial stalk rot is a disease that affects maize plants and can significantly reduce crop yields. It is caused by the bacteria Erwinia carotovora f. sp. zeae. It infects the stems of maize plants, causing them to rot and eventually leading to plant death.
Bacterial Stalk Rot disease management in Maize
The causal organism of Bacterial Stalk Rot Disease
Bacterial stalk rot of Maize, caused by Erwinia carotovora f. sp. zeae (now Pectobacterium chrysanthemi pathovar. zeae), is a severe disease of Maize that can result in significant yield losses. The disease starts with the premature wilting and yellowing of the uppermost leaves, which is soon followed by the lower leaves. The rot can spread from the base of the plant upwards (basal rot) or the top of the plant downwards (top rot). The infected tissue becomes brown, soft, and water-soaked in severe cases. The stalk may collapse into a soft mass of disintegrated tissue.
The Disease cycle of Bacterial Stalk Rot disease
Bacterial Stalk Rot, caused by the bacterium Erwinia carotovora, can survive in old stalks above ground. The disease is spread in water and can infect plants through natural openings and wounds. It is most prevalent in areas with high rainfall or where surface irrigation using pond or lake water is used, the bacteria can be washed onto the stalks and leaves, where they can enter the plant through openings. Flood irrigation can also spread the bacteria to the base of the stalks.
Causes/conditions favorable for Bacterial Stalk Rot disease spread in the field
- High temperatures and high relative humidity can create an environment conducive to developing bacterial stalk and top rot in Maize.
- Overhead irrigation and heavy rainfall can also contribute to the spread of the disease by providing conditions that allow the bacteria to thrive.
- Additionally, water sources such as lakes, ponds, and slow-moving streams may contain the bacteria that cause the disease, which can then be spread to crops through irrigation water.
Symptoms of Bacterial Stalk Rot disease
- Bacterial stalk rot of Maize is a severe disease that can cause significant yield loss. The initial symptoms of the disease include discoloration leaf sheath and stalk at a node, which can progress to lesions on the leaves and sheath.
- The disease can quickly spread to the stalk and leaves, leading to a foul odor, the collapse of the top of the plant, and complete rot of the stalk.
- The disease can affect the plant at any node, from the soil to the ear leaves and tassels. Infections high on the plant can impair tasseling and pollination.
- Although the bacteria do not usually spread from plant to plant, they can be vectored by insects, which can contribute to spreading the disease within a field. Splitting the stalk of infected plants reveals internal discoloration and soft, slimy rot that usually begins at the nodes.
- Diseased plants are often found scattered throughout the field. St