Jaaginema geminatum

Jaaginema geminatum is a filamentous cyanobacterium that often thrives in aquatic environments, including rice paddies. While it is classified biologically as a species of cyanobacteria, in agricultural contexts, it acts as a harmful organism that interferes with the growth and development of crops, particularly rice.

The organism is characterized by the formation of dense mats or filaments that grow on the water surface and substrate. This biological activity is driven by photosynthetic processes, making the pathogen particularly aggressive in shallow, warm, and nutrient-rich waters commonly found in rice fields.

Rice (Oryza sativa) is the primary crop affected by this pathogen. During the early stages of crop development, the filaments of Jaaginema geminatum entangle the young seedlings, blocking light penetration and physical space, which suppresses the normal physiological growth of the crop.

Visible symptoms include the presence of greenish-black slimy mats covering the water surface and wrapping around rice stalks. The infestation leads to stunted plant growth, reduced tillering, and potential seedling mortality, which significantly lowers the overall plant density and total harvest yield.

Management strategies for this organism focus on water management and environmental control. Key preventive measures include:

• Maintaining proper water circulation in rice paddies.
• Monitoring nutrient runoff, especially phosphorus levels, to prevent algal blooms.
• Applying selective algaecides to control population explosions.
• Implementing integrated pest management practices to ensure crop vigor.