White-tip disease of rice

The pathogen responsible for this condition is the foliar nematode Aphelenchoides besseyi. It is a highly specialized plant-parasitic nematode that predominantly inhabits the aerial parts of plants, such as leaves and floral tissues, rather than the roots.

Rice is the primary host crop, although the nematode also infests strawberry plants, causing the 'summer dwarf' disease, as well as various grasses and other monocot species. The nematode typically enters the host tissue through the stomata or wounds caused by external factors.

The characteristic symptoms include chlorosis or necrotic white tips on the youngest leaves, which eventually turn brown and become frayed. Infested plants often exhibit stunted growth, reduced tillering, and distorted panicles, which significantly impact the overall grain quality and yield.

The nematode spreads primarily through infected seeds and water during irrigation. High humidity and moderate temperatures are ideal for its reproduction and migration. Once introduced to a field, it can persist in plant debris and soil, making control measures vital for sustainable production.

Prevention and management strategies focus on sanitation and cultural practices. Using nematode-free certified seeds is the most effective defense. Hot water treatment of seeds (soaking in water at 50–55°C for 10–15 minutes) is a standard practice to eliminate internal infestations before planting.