VG04025 Parsley Root Rot

This project details the outcomes of a 12-month scoping study of root rot of parsley which investigated primary causes and treatments for root rot in the States of NSW, Queensland and Victoria.

Growers reported that root rot of parsley caused up to 100% crop losses in Queensland and Victoria
for a number of years.

In Victoria the problem is worse in late autumn through winter when
conditions are cool and wet. In Queensland growers reported root rot was worse during the wet

Some Queensland growers have established hydroponic production to avoid crop losses and
maintain production through the wet season.

Liz Minchinton Fiona Thomson
Desmond Auer Heidi Martin
Lindsay N. Trapnel Len Tesoriero
Leif Forsberg Savitri Nadesan

Slobodan Vujovic

VG04045 Parsley Root Rot
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Scientists have identified the cause and control of a root rot disease that severely affects Victorian
parsley crops. The disease can cause up to 100% crop losses.

Root rot attacks seedlings and mature plants, generally at the soil line causing a spongy, dull brown
rot and a massive loss of roots. It results in the complete collapse of the shoot system.

Field trials conducted on a commercial crop of parsley in Victoria identified two fungicides which
completely controlled the disease. These fungicides are from different chemical groups, therefore
their use should conform to management of chemical resistance strategies.

Parsley root rot in Victoria was associated with the water mould fungi Pythium and Phytophthora.

The disease is prevalent during the late autumn and winter, especially after heavy rains when soil
temperatures are low. Eight-week-old crops are highly susceptible.

Surveys of parsley crops in Queensland, New South Wales and Victoria indicated that a similar
disease occurs on parsley in Queensland during periods of warm wet weather. Root rot was of lesser
importance on parsley crops in New South Wales.

In laboratory trials conducted in Queensland and New South Wales, a bacterium and a number of
fungi, other than water moulds, caused collar rot, root rot and crown rot.

The cause and control of root rots in Queensland parsley crops now needs to be addressed as well as
the control of fungi other than water mould, which cause collar and crown rots.

Information resulting from this research is being presented in a poster on parsley diseases and in a
notebook that will be distributed nationally to industry through the Vegetable Industry Development
Officer network.

This research was led by scientists at the Department of Primary Industries Victoria Knoxfield Centre,
in collaboration with Queensland Department of Primary Industries and Fisheries and New South
Wales Department of Primary Industries.

The project was
facilitated by Horticulture Australia Limited (HAL) in partnership with Federation of Potato and
Vegetable Growers Australia Limited (AUSVEG) and was funded by the National Vegetable Levy.

The Australian Government provides matching funding for all of Horticultural Australia’s Research
and Development activities.

The researchers gratefully acknowledge the financial support of the
Department of Primary Industries through Primary Industries Research Victoria.

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