Look and report
Tomato yellow curl leaf virus is a declared pest in Western Australia.
Tomato yellow leaf curl virus is not known to occur in Western Australia (WA) and must be reported to the department if found or suspected to be present. Begomovirus coheni is known to occur in Queensland and Victoria. Early detection and reporting of possible cases will help protect the WA tomato industry.
What is Begomovirus coheni?
Begomovirus coheni, previously known as Tomato yellow leaf curl virus (TYLCV), is a very damaging virus disease of tomato crops in tropical and warm temperate regions of the world, causing losses of up to 100%. This virus is absent from WA.
What plants are affected?
The main host of Begomovirus coheni is tomato, but the disease can also affect French bean, chilli, eggplant and capsicum. Some weeds and ornamental plants such as lisianthus and petunias can carry the virus and may not show obvious symptoms.
What do I look for?
- Tomato plants infected early are severely stunted, with small abnormally shaped leaves, and will not produce fruit.
- Leaves that develop soon after infection are cupped downward, whereas later leaves yellowed, abnormall shaped, with edges that curl upwards and possibly some curling between leaf veins.
- Flowers either do not develop or fall off.
- When older plants are infected, fruit that is already forming ripens normally, but no new fruit is formed after the infection.
- Begomovirus coheni can be confused with several other conditions such as tomato big bud (phytoplasma), herbicide damage and phosphate or magnesium deficiency.
- In French bean, leaves crumple, thicken curl upwards, and abnormal side shoots form.
What damage can this disease cause?
Begomovirus coheni can completely destroy tomato crops , where whitefly vectors occur. It also causes disease in French bean, chilli, capsicum and some ornamental plants.
Legal duty to report
Begomovirus coheni is considered absent from Western Australia and is a quarantine pest. Tomato yellow leaf curl virus is not known to occur in WA. Begomovirus coheni is a declared pest under section 12 of the Biosecurity and Agriculture Management Act 2007.
This means that any person who finds or suspects the presence of Tomato yellow leaf curl virus in WA must report it to the department.
WA's freedom from Begomovirus coheni is supported by general and specific surveillance and specific import requirements to prevent its entry.
How does Begomovirus coheni survive and spread?
- Begomovirus coheni is spread by at least two subtypes of an insect vector, silverleaf whitefly (Bemisia tabaci). Bemisia tabaci Middle East-Asia Minor 1 (MEAM1) is under official control Western Australia, whereas B. tabaci Mediterranean (MED) is a seclared prohibited pest to Western Australia These whiteflies pick up the virus by feeding on infected host plants and spread the virus to healthy plants which show the symptoms 10 to 21 days later.
- Silverleaf whiteflies are common in Carnarvon and feed on many types of plants.
- Begomovirus coheni is not known to spread via seed or when crops are handled or pruned.
- Infected weeds such as blackberry nightshade (Solanum nigrum) and mallow (Malva parviflora) can act as reservoirs of the virus.