Potato Leafroll Virus

  • Symptoms

  • Trigger

  • Biological Control

  • Chemical Control

  • Preventive Measures

Potato Leafroll Virus

PLRV

Virus


In a Nutshell

  • Younger leaves have upturned margins and develop interveinal chlorosis.
  • Older leaves are upturned, stiff and brittle with a purple underside.
  • Plant growth is stunted and stalks are stiff and point upwards.
  • High levels of infection reduce tuber yield and marketability.

Hosts

Potato

Symptoms

Visible symptoms vary according to plant variety, environmental conditions and type of infection. Primary infection, which is caused by aphids, is visible mostly on younger leaves. The margins start to roll upwards and become dry, pale or develop interveinal chlorosis. In plants grown from a contaminated tuber (secondary infection), older leaves are upturned, stiff and brittle with a purple or red underside, while younger ones are upright and pale green or chlorotic. The plants growth is stunted and the stalks are stiff and point upwards. High infection levels reduce tuber yield and marketability.

Trigger

Initial transmission occurs when plants get infested and fed upon by virus-carrying aphids during the growing season. Secondary infection takes place when contaminated tubers are planted, and potato plants grow from them. Aphids transmit the infection to other healthy plants. The virus is persistent for the life of the aphid, so the potential of infection is high. To transmit the virus, the insects need to feed on the plant for at least 2 hours. Humid soil promotes the risk of infection.

Biological Control

Direct treatment of the virus is not possible, but reducing aphid population by means of predators or parasitoids is a helpful preventive measure. Ladybirds, soldier beetles, lacewings, and some types of midges and flies eat adults aphids and larvae. Parasitic wasps could also be used.

Chemical Control

Always consider an integrated approach with preventive measures together with biological treatments if available. Chemical treatment of viral diseases is not possible. However, the aphid population can be controlled to some degree. Apply insecticides in the early phases of crop growth for example.

Preventive Measures

Use seed tubers from healthy plants or acquire certified seeds.,Plant resilient varieties if available.,Monitor the field, pick and destroy diseased plants.,Destroy weeds and volunteer plants that can host the virus and feed the aphids.