Sugarcane xanthomoniasis

Causative agent and disease type. The disease is caused by the bacterium Xanthomonas sacchari. It is a vascular pathogen that colonizes the xylem of the plant. The infection is classified as a bacterial wilt or vascular necrosis, significantly disrupting the translocation of water and nutrients within the sugarcane plant.

Host crops. The primary host for this pathogen is sugarcane (Saccharum officinarum) and related species within the genus. While it is highly host-specific, the prevalence of susceptible high-yield hybrids in commercial farming makes this pathogen a significant economic concern in sugarcane-producing regions across the globe.

Symptoms and signs. The characteristic symptoms start as long, narrow chlorotic streaks on the leaves running parallel to the leaf veins. As the disease progresses, these streaks turn necrotic, often showing a reddish-brown or dark color. In advanced stages, the internal stem tissues show vascular browning, and under high humidity, bacterial ooze can be observed on the cut surfaces of the stalks.

Environmental conditions. The development of Xanthomonas sacchari is favored by warm, humid conditions, especially during the rainy season. The bacteria spread through rain splashes, irrigation water, and the movement of infected plant material. Mechanical transmission through pruning or harvesting tools is also a major factor in the rapid spread of the disease within a plantation.

Harmfulness and protection measures. The disease can cause severe crop yield losses, reduced sucrose content, and poor stalk quality. Effective management strategies include:

• Utilizing pathogen-free certified seed cane for planting.
• Selecting and planting resistant or tolerant sugarcane varieties.
• Sterilizing equipment between fields to prevent cross-contamination.
• Managing insect pests that cause wounding and facilitate bacterial entry.
• Implementing strict quarantine protocols to prevent the introduction of infected material into new areas.