Downy Mildew Disease (DMD), known locally as Matenda a Nanzikambe, is a dangerous disease caused by microorganisms called oomycetes. It is most common in hot and warm areas, especially where maize is grown extensively.

Symptoms of the Disease

• Fungal Growth: One of the most visible signs is a cotton-like or greyish mold growing on the underside of maize leaves.
• Discoloration: Yellow or white stripes appear along the edges of the leaves.
• Stunted Growth: The maize plants fail to grow properly and appear shriveled or stunted.

Prevention Measures (Before Planting)

To prevent the disease, farmers are encouraged to take the following steps before and during planting:

• Deep Plowing: Ensure the soil is turned deeply.
• Certified Seeds: Use certified seeds from reliable sources, such as Seed Co.
• Seed Treatment: Apply Metalaxyl to seeds at a rate of 6 grams per 1 kilogram of seed during planting.
• Field Placement: Avoid planting maize near sugarcane.
• Crop Rotation: Rotate maize with other crops like beans or groundnuts.
• Proper Spacing: Plant with correct spacing to ensure good air circulation within the field.

Management and Control

If the disease appears in the field, the following actions are advised:

• Removal: Uproot and bury all plants showing symptoms.
• Limit Movement: Reduce movement within infected fields to prevent spreading the disease.
• Avoid Ratooning: Do not leave sorghum stalks (ratooning) in the field, as they can harbor the disease-causing organisms.
• Chemical Application: Fungicides such as Azoxystrobin (18.2%), Difenoconazole (11.4%) SC, and Metalaxyl (Ridomil Gold) are effective in controlling the disease.
• Post-Harvest Sanitation: After harvesting, all crop residues from infected fields must be burned to ensure the disease does not return in the following season.

Summary of Recommended Fungicides for Downy Mildew

Based on the provided information, here are the chemical treatments and application rates recommended for managing Downy Mildew Disease (DMD) in maize:

Key Cultural Management Practices

In addition to chemical treatments, these practices are essential for total disease control:

• Sanitation: Uproot and bury any plants showing symptoms to stop the spread.
• Post-Harvest: Burn all crop residues from infected fields after harvest to prevent the disease from returning next season.
• Avoidance: Do not leave stalks (ratooning) in the field, as they can host the pathogens.
• Source: Use certified seeds, from Seed Co, to ensure a healthy start.