Pythium and Parsnip canker

IPM options to control Pythium induced root rots are being investigated by Dr Liz Minchinton and her team at DPI Knoxfield.

The project , VG08026 – “Identification of IPM strategies for Pythium induced root rots in Apiacae vegetable crops”, is funded by Horticulture Australia Limited.

Parsnip Canker is prevalent in autumn sown crops harvested in spring and appears as sunken brown shoulder lesions on the root.

Pythium causes :

• damping off of direct sown crops such as Carrot, Parsley & Parsnips seedlings
• cavity spot on Carrots
• root rots in many hydroponic crops
• and predisposes Parsnips to Canker

“Many fungi are associated with Parsnip Canker and it is an extremely difficult disease to control”, said Dr Minchinton.

Research from WA recommends planting Broccoli before Parsnips as Broccoli is not a host of Pythium.

Field trials in 2009 showed applications of a Pythium selective fungicide could reduce Parsnip Canker by 30% on sandy soils but the fungicide was ineffective in clay soils.

Canker also appeared worse in Parsnips grown in heavy soil where cool, wet conditions favour Pythium infections.

“As the soil began to warm up after winter, other pathogens including Phoma, Rhizoctonia and Fusarium, became active in both, clay and sandy soils”, said project scientist Dr Joanna Petkowski.

Where possible, avoid sowing Parsnip crops in heavy soils during autumn.

The VGA Industry Development Officers are available to assist all vegetable growers.

If you need to get in touch with current research, or research that has been completed in the past and would like more information, please contact :

                 Slobodan Vujovic

                                  Mobile : 0422 583 784

                                  Email : idoeast@vgavioc.org.au