Rice Yellow Mottle Virus | 23 Jun 2025

Source: DTE

Rice Yellow Mottle Virus (RYMV), a highly contagious plant disease, is ravaging rice crops across Africa, leading to major yield losses and posing a serious threat to food security.

Rice Yellow Mottle Virus

• Origin & Spread: It originated in the Eastern Arc Mountains of Tanzania in the 1800s from wild grasses, spreading to the Kilombero Valley and Morogoro (Tanzania) before expanding across Sub-Saharan Africa.
  • Though endemic to Africa, it has also been reported in Turkey.
• Causal Agent & Transmission: The virus is a member of the Sobemovirus known for its high genetic variability, allowing it to evolve rapidly.
  • Vectors include beetles (Chrysomelidae), grasshoppers, cows, rats, and donkeys.
  • It spreads through insect vectors, mechanical means (sap or water contact), and root injuries, but is not seed-borne.
• Symptoms: Yellow-green streaks appear on young leaves, leading to mottling and leaf twisting. Plants show stunted growth, poor panicle formation, sterility, and may eventually die.
• Impact on Rice Production: Yield losses range from 10% to 100%, with early infection causing greater damage.