Maize bushy stunt

Maize bushy stunt is a severe systemic plant disease caused by the mollicute Spiroplasma kunkelii. It predominantly affects maize crops, leading to significant yield losses due to stunted growth and reduced grain production capacity.

The primary vector responsible for the transmission of the pathogen is the corn leafhopper, Dalbulus maidis. The bacterium is acquired by the insect during feeding and is subsequently transmitted to healthy plants. Once inside the host, the pathogen colonizes the phloem, systemically impairing the plant's nutrient transport system.

Symptoms of the infection are distinct and easy to identify in the field. Affected plants show severe stunting of internodes, resulting in a bushy appearance. Leaves often exhibit chlorosis or reddish discoloration, and the plants produce multiple small, poorly filled, or completely sterile ears.

The development and spread of the disease are highly dependent on the ecology of the leafhopper vector. Warmer climates that support year-round breeding of Dalbulus maidis are particularly prone to high infection rates. The pathogen survives in perennial grasses and volunteer corn, serving as a reservoir for annual re-infection.

Management of the disease requires an integrated pest and disease control approach. Key interventions for producers include:

• Planting resistant or tolerant maize hybrids.
• Implementing insecticide programs to control leafhopper populations.
• Synchronizing planting times to avoid peak vector activity.
• Eliminating volunteer corn and maintaining field hygiene to reduce inoculum sources.