VG00031 Peas – downy mildew & collar rot

Downy mildew (caused by Peronospora viciae) and collar rot (caused by Ascochyta pinodella and Ascochyta pinodes) are the two most common and important diseases of processing pea crops, adversely effecting yield and quality.

Cost-effective management strategies for these two diseases are therefore vital for the sustainability of processing pea production in Australia.

Infected seeds and soils are common sources of inoculum for both types of pathogen.

This four page brochure summarises appropriate management strategies for preventing seedling and field infections by these pathogens.

Conclusions :

• Prior to this project, there was no cost effective control method for field downy mildew on processing pea crops beyond the 6 nodes stage.
• The project identified three relatively low cost fungicide products, chlorothalonil (Bravo®), mancozeb (Penncozeb®), and phosphorous acid (Agri-Fos®), for field downy mildew and collar rot management on processing pea crops.
• Phosphorous acid + mancozeb mixture was the most consistent and effective foliar treatment for field control of downy mildew, but had no effect on collar rot.
• Phosphorous acid or mancozeb alone had little or no effect on downy mildew.
• Phosphorous acid + chlorothalonil, the second best treatment against downy mildew, was also effective in reducing collar rot severity.

Acknowledgements :

The funding of this project by Horticultural Research and Development Corporation, processing pea growers, Simplot Australia Pty Ltd, McCain Foods (Australia) Pty Ltd and Syngenta Pty Ltd, is gratefully acknowledged.

We would also like to thank all the growers and field officers from Simplot Australia Pty Ltd and McCain Foods (Australia) Pty Ltd, who assisted in the project studies.

Lyndon Butler and Vaughan Trebilco of Forthside Vegetable Research Station are acknowledged for their assistance in the seed treatment trials at the station and for the use of their mechanical pea viner and pea maturometer.

Serve-Ag Research staff who assisted in this project are Sarah Lamprey, Pam Cox, Belinda Mathews, and Rebecca de Courcy.