Sugarcane grassy shoot

Grassy shoot is a destructive systemic plant disease caused by the phytoplasma Candidatus Phytoplasma sacchari. This pathogen specifically targets sugarcane, significantly hindering its growth and leading to major economic losses in the sugar industry worldwide.

The characteristic symptom of the disease is excessive tillering, where the plant produces a dense cluster of thin, pale, and spindly shoots that resemble a bunch of grass. These affected plants typically exhibit severe chlorosis, stunted growth, and a drastic reduction in their ability to store sucrose in the stems.

The transmission of the disease primarily occurs through the use of infected stalks as propagation material. Additionally, the phytoplasma is spread in the field by insect vectors, specifically sap-sucking leafhoppers (such as Deltocephalus vulgaris), which carry the pathogen from diseased sugarcane to healthy crops.

Environmental factors, such as temperature and humidity, play a crucial role in the survival of the insect vectors and the overall incidence of the disease. Inadequate weed management in and around fields can also serve as a reservoir for the pathogen, facilitating constant re-infection of new plantings.

Effective management and prevention of Grassy shoot disease require a multi-faceted approach:

• Always utilize disease-free, certified seed cane for planting.
• Apply heat treatment (hot water or moist air) to seed cuttings to eliminate the phytoplasma.
• Conduct regular field inspections to rogue and destroy any symptomatic plants immediately.
• Implement rigorous insect control programs to minimize the population of leafhopper vectors.
• Maintain good field sanitation and ensure proper spacing to reduce overall disease pressure.