Rice Yellow Mottle Disease and Control

Rice Yellow Mottle Virus is endemic, outbreak is common in the African continent and it’s mostly found in countries that grow rice on large scale.

Mode of Transmission

The virus is a member of the genus Sobemovirus, it can overcome resistance genes of various rice varieties and it is transmitted by beetles, grasshoppers, rats, cows and other insects.

Also irrigation water and contact between healthy and infected plant tissues or crop residues can spread the infection through the roots.

The virus can reduce yield greatly from 30 to 100%, it’s impact varies from one variety to another and early outbreak leads to very high loss. The nature of outbreak of rice yellow mottle disease poses a serious threat to suitable rice production especially in the Sub-Saharan countries. 

 The virus can also been found on roots of infected plants, it can infect plants through injured roots and research has shown that the virus has also been detected on seeds.

Symptoms

Infection by RYM virus is systemic affecting infected  rice plants and resulting into signs listed as follows:

  • Infected plants will have stunted growth,
  • Yellow stripes and spots on the leaves,
  • Maturing rice plants shows sign of sterility and empty spikelet
  • Mottled and twisted leaves,

Control

  • Plant RYMV resistant varieties only,
  • Changing the nursery site,
  • Early planting,
  • Good management i.e timely weed or weed control,
  • Crop rotation can prevent the build up of the RYM virus and vectors,
  • Use of insecticide to control insects,
  • Burn straws after harvesting and destruction of infected plants,
  • Reduction of the use of fertilizer like urea
  • Flooding of tilled rice plots

Rice farmers must frequently observe their plants so that control of the virus that has the capacity to reduce yield can be quickly controlled and good management practices must be implemented at every planting season for successful cultivation of rice.

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