AgMemo - Livestock news, June 2018

Page last updated: Wednesday, 20 June 2018 - 9:00am

Please note: This content may be out of date and is currently under review.

Manage aphids to manage sub clover red leaf syndrome 

A clover leaf with aphids on it
SbDV is transmitted by certain aphid species that migrate from green-bridge hosts to colonise subterranean clover. Foxglove aphid (Aulacorthum solani) and pea aphid (Acyrthosiphon pisum) are the primary vectors. Blue green aphid (Acyrthosiphon kondoi) may act as an inefficient vector.

Producers are being advised to check their pastures this winter and spring for aphids that might infect sub clover plants with a virus that causes the red leaf syndrome.

Management options include the use of insecticides and sowing alternative pasture species.

There has been considerable concern among livestock producers regarding recent outbreaks of subterranean clover red leaf syndrome. Symptoms include red leaves, stunted plants and even premature plant death.

The Department of Primary Industries and Regional Development (DPIRD) investigated the outbreak in 2017 finding that of the subterranean clover plants tested, 80% with obvious red leaves were infected with Soybean dwarf virus (SbDV) compared to just 2% without obvious symptoms.

SbDV is spread by aphids persistently (once acquired the aphid has it for life) and repeat infection can occur.

Its incidence in a subterranean clover pasture will vary from season to season depending on the abundance and distribution of alternative plant hosts and aphid vector species.

The symptoms can occur as isolated patches in paddocks, to whole paddocks being affected. However, the presence of red-leaves does not necessarily indicate viruses are present.

SbDV is not seed-borne and therefore is not present in the seed bank or in commercial seed stocks.

For more detailed information visit the subterranean clover red leaf syndrome on the department’s website.

Clover showing red leaf syndrome
Subterranean clover plant SbDV-infected with red leaves. Reddening is from the leaf margins inwards.

For more information contact Paul Sanford, DPIRD Senior Research Officer, Albany on +61(0)8 9892 8475 or Kevin Foster, UWA Pasture Researcher, Nedlands on +61 (0)8 6488 2220.