Pacific Pests, Pathogens and Weeds

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Summary

• Worldwide distribution. Present in several Pacific island countries. Only found in sweet potato. The abbreviation is SPVG. It is a potyvirus.
• Damage: on its own no symptoms and probably little impact on yield; with other viruses, e.g., Sweetpotato feathery mottle (and perhaps Sweetpotato chlorotic stunt virus), SPVG multiplies many times normal resulting in lower yields.
• Detection: grafting to Ipomoea setosa, or using ELISA and/or PCR.
• Natural enemies: there are many parasitoids and predators of aphids, but aphids are not commonly seen on sweet potato in Pacific island countries, so their effect is probably small.
• Spread by aphids, infected cuttings and storage roots.
• Cultural control: use planting material from healthy 'seed' scheme (i.e., mother plants regrown from meristems after heat treatments and tested negatively for SPVG.
• Chemical control: Not a method to use as insecticides cannot kill the aphids before they have transferred the virus.