Don McCaffery Background to Beet western yellows virus in canola 2014-0805

Background to this season’s Beet western yellows virus

problemDon McCaffery

NSW DPI

Orange

5 August 2014

So how did this problem develop?

Presence of green peach aphid (GPA)– GPA is endemic

Right conditions for pest population growth Late summer alternative hosts available Warm, dry conditions optimum for GPA Lots or early sown canola & crops in aphid flight

zone GPA main vector (transmitter) for BWYV

Why did the aphids infect where they did?

Stress related?– Divided opinion among

researchers– There was no moisture

stress involved in SA– Other possible stresses

• Group B residues• Nutrition• Waterlogging• Off label products and

at off label rates

Trangie on 28 May, sown 1 AprilGPA x moisture stress

What has happened to date

18 June - SA – major issue identified with BWYV The virus quickly appeared in other regions of SA,

Mallee of Vic -19 June and southern NSW -1July First positive for BWYV in NSW was Young in trial

plots on town boundary– Early May

Early infections have done the most damage

Distribution based on samples submitted

Source: DEPI, Horsham Vic

What has happened to date (cont’d)

Information and updates delivered through PestFacts, press releases and other grains websites

Media went into overdrive AOF has coordinated two teleconferences

– State agency researchers, canola industry and GRDC

– 4 July & 31 July

GPA Feeding damageTrangie 2014 – no virus

Feeding damage

Trangie 2009

GPA feeding + BWY virus

GPA feeding + BWY virus