December pest of the month: Potyvirus
5 November 2024
Potyviruses are a major and widespread threat to vegetable and ornamental crops, transmitted mainly by aphids and infected plants, making them highly contagious in nurseries.
Symptoms
Potyvirus symptoms can be challenging to identify and are often mistaken for issues such as nutritional disorders, edema, phytotoxicity or insect/mite damage. Common symptoms to watch for include mottled, chlorotic or deformed leaves. However, symptoms may vary depending on the host plant and, in some cases, different viruses can produce similar signs.
Affected plants
Potyviruses can affect a wide range of crops, including tomatoes and potatoes (Solanaceae), pumpkins and cucumbers (Cucurbitaceae), cabbage and broccoli (Brassicaceae), as well as beans and peas (Fabaceae), with ornamental plants and weeds also at risk.
Management
Once a plant is infected with Potyvirus, there is no cure. It’s best to hygienically remove and dispose of infected plants. Composting them can spread the infection.
To minimise the risk of spread:
- implement proactive weed control to eliminate potential virus reservoirs
- plant resistant varieties when they’re available
- avoid planting new crops next to infected ones to prevent cross contamination.
If you suspect an infection
If you suspect a virus infection in your plants, it is crucial to diagnose it. We recommend that growers send plant stems, including new growth showing symptoms, to a diagnostic laboratory for diagnosis.
Until the end of 2025, Grow Help Australia, a service that helps growers identify pests, is offering nurseries six free diagnostic samples per year, making it easier to stay ahead of potential outbreaks. For more information on virus management, visit the Pest ID tool at pestid.com.au.
