Sweetpotato feathery mottle

General information

Sweet potato feathery mottle virus is the most common and widespread virus infecting sweetpotato, occurring in almost all countries where the crop is grown. The virus can reach high levels of infection in crops propagated from infected material or grown near infected crops, allowing aphid transmission from crop to crop.

The virus causes reduced yields and a reduction in the quality of harvested roots.

Cause

Sweet potato feathery mottle virus (Potyvirus).

Symptoms

The variety, rate of growth, plant age and weather conditions all influence symptom development. Symptoms include a mild mottle on young leaves, yellow (chlorotic) spotting often surrounded by a purple margin or irregular chlorotic patterns along the midrib. Symptoms may be more prevalent on older leaves. Plants of many varieties develop only transient, mild symptoms. Reduced plant vigour in the early establishment phase of the crop is common but not recognised until infected material is grown alongside PT material. Storage roots elongate and become thinner in successive generations where infected plant material is used. Storage roots can display russet cracking and pale flesh colour in orange-fleshed varieties.

How does it spread

The virus is spread by aphids in a non-persistent manner and by using infected planting material.

Crops affected

The host range of the virus is restricted to sweetpotato and other Ipomoea species.

Control options

Use only good-quality planting material, preferably from tested, virus-free material. Locate planting material nurseries remote from sweetpotato crops to reduce the risk of infection from diseased crops. Discard plants with probable symptoms of virus disease.

Chemical registrations and permits
Check the Australian Pesticides and Veterinary Medicines Authority chemical database and permit database for chemicals registered or approved under permit to treat this disease on the target crop in your state or location. Always read the label and observe withholding periods.

Further information