Downy Mildew outbreak threatens maize production in southern region

By Michael Martin//MALAWI

The Ministry of Agriculture, Irrigation and Water Development has confirmed an outbreak of Downy Mildew Disease (DMD), a serious fungal like disease affecting maize and other cereal crops in Malawi.

According to a press statement signed by Secretary for Agriculture Davis Sado, the disease has so far been detected in areas under Blantyre and Machinga Agricultural Development Divisions (ADDs).

The Ministry has warned that if the outbreak is not contained early, it could spread to other parts of the country and cause significant losses to maize main staple crop in thecountry.

“Downy Mildew Disease affects maize, sorghum, sugarcane and millet, and is known to cause total crop failure when infection occurs at an early growth stage,” reads part of the statement.

The disease is caused by water mould pathogens belonging to the genera Peronosclerospora, Sclerospora and Sclerophthora, which thrive in humid conditions.

According to the Ministry, symptoms of the disease include yellow or pale streaks on young leaves, stunted plant growth, and eventual death of infected seedlings within a few weeks.

“In older plants, the disease causes chlorotic streaks that begin at the base of the leaf, along with abnormal tassel development and poor ear formation,” the statement adds.

The Ministry further noted that a white, mould like growth on the underside of maize leaves is the clearest sign of Downy Mildew infection.

In an interview, agricultural expert Tamani Nkhono Mvula said the outbreak is likely linked to the current rainy conditions, which have created a favourable environment for the disease to spread.

“High humidity and moderate temperatures between 21 and 26 degrees Celsius are ideal for Downy Mildew spores to multiply and spread,” explained Mvula.

He added that infected seed and crop residues left in fields from previous farming seasons may also be contributing to the outbreak.

Mvula emphasized the need for farmers to act quickly, warning that Downy Mildew can wipe out entire maize fields if not managed early.

He advised farmers to plant certified seed from approved suppliers to reduce the risk of introducing the disease into their fields.

Mvula also encouraged farmers to treat seed with recommended chemicals such as Metalaxyl before planting to protect young seedlings.

“Proper land preparation, including deep ploughing, is an important step in reducing disease-causing organisms in the soil,” he said.

Experts have further warned against planting maize near sugarcane or intercropping it with host crops, as this increases the risk of cross-contamination.

During the growing season, farmers are advised to regularly inspect their fields and immediately uproot and bury infected plants.

“Early removal of infected plants can significantly slow the spread of spores,” Mvula said.

He also cautioned farmers to avoid unnecessary movement in infected fields, as spores can be easily transferred from one plant to another.

After harvest, the Ministry recommends destroying infected crop residues, including through burning, to prevent the disease from surviving into the next season.

Crop rotation with legumes and pulses has also been encouraged as a long-term strategy to break the disease cycle.

Despite the seriousness of the outbreak, the Ministry has not yet outlined specific emergency response measures being implemented at national level, raising concern among some farmers who fear delayed action could worsen the situation.

However, Mvula believes timely reporting by farmers can help agricultural authorities respond more effectively.

“Farmers should report any suspected cases to agricultural extension workers or nearby government offices without delay,” he said.

He also stressed the importance of farmer education, noting that Downy Mildew Disease is often confused with Maize Streak Virus, which requires different management approaches.

The Ministry has clarified that Downy Mildew differs from Maize Streak Virus in both symptom pattern and mode of spread.

With maize central to food security in Malawi, experts warn that unchecked spread of the disease could have serious national implications.

Both the Ministry and agricultural specialists are urging cooperation among farmers, extension officers and local authorities.

As the rainy season continues, vigilance and early action remain critical to protecting maize crops and safeguarding household food security across the country.