Sources of PLRV
Infected ware and processing potato crops and self-sown potato plants often act as a source of infection for young potato crops. In 2012, self-sown potatoes were collected from four sites and PLRV was detected at three of these at levels of 2–19%.
Other plant hosts of PLRV include tomato, capsicum and solanaceous weeds such as nightshade, wild gooseberry and thornapple.
Only a few aphid species transmit PLRV. Among these, the green peach aphid (Figure 3) is highly efficient in spreading PLRV and commonly occurs in potato growing areas. There is more information on Green peach aphid: potato pest in Indonesia and Western Australia.
Spread by aphids
PLRV is persistently transmitted by aphids which means that once infected an aphid can transmit PLRV for the rest of its life and spread the virus over long distances. An aphid needs to feed on an infected plant for several hours to acquire the virus which then spreads through its body and lodges in the salivary glands. The virus-carrying aphid then flies off, and when it lands and feeds on another plant it transmits the virus to the new plant.
Management strategies
- Plant only certified or virus-tested tubers. See Potato seed certification.
- Remove all self-sown potatoes and solanaceous weeds.
- Avoid planting new and seed potato crops near old, ware or processing crops.
- Rogue (remove) infected plants showing virus symptoms from seed potato crops.
- Apply neonicotinyl insecticides early in the life of the crop to control early aphid arrivals, use as directed on label. Do not wait until aphids are visible as this will be too late.
Correct diagnosis is essential for effect disease control. A commercial diagnostics service is available through DDLS - Seed testing and certification services.
Acknowledgment
Funding for the Generation 2 seed potato crop virus survey is supplied by the Agricultural Produce Commission - Potato Producers Committee.