Investigations and developing integrated management stategies for carrot powdery mildew Andrew Watson Department of Primary Industries Project Number: VG08044 VG08044 This report is published by Horticulture Australia Ltd to pass on information concerning horticultural research and development undertaken for the vegetables industry. The research contained in this report was funded by Horticulture Australia Ltd with the financial support of the vegetables industry. All expressions of opinion are not to be regarded as expressing the opinion of Horticulture Australia Ltd or any authority of the Australian Government. The Company and the Australian Government accept no responsibility for any of the opinions or the accuracy of the information contained in this report and readers should rely upon their own enquiries in making decisions concerning their own interests. ISBN 0 7341 2967 X Published and distributed by: Horticulture Australia Ltd Level 7 179 Elizabeth Street Sydney NSW 2000 Telephone: (02) 8295 2300 Fax: (02) 8295 2399 © Copyright 2012 HAL Project Number: VG08044 (31 May 2012) Investigations and Developing management strategies for carrot powdery mildew Andrew Watson et al. NSW DPI VG08044 Andrew Watson NSW Department of Primary Industries Yanco Agricultural Institute Yanco NSW 2703 Phone 02 69 512611 Fax 02 69 512719 Email: [email protected] Co-authors: Dr Hoong Pung (Peracto-Tasmania) and Barbara Hall (SARDI) Researchers in New South Wales-Andrew Watson, Lee Browne and Meryl Snudden Researchers in Tasmania-Hoong Pung and Susan Cross Researchers in South Australia-Barbara Hall, Peter Cavallaro, David Cavallaro and Lee Bartlett This report covers project activities undertaken from October 2008 to May 2012 to assess the impact of powdery mildew on carrot growth, harvest, yield and quality, to assess the efficacy of chemical and non-chemical products for powdery mildew control and to develop integrated methods for disease control. Report Completed–May 2012. This project has been funded by HAL using the vegetable levy and matched funds from the Australian Government. Any recommendations contained in this publication do not necessarily represent current HAL Limited policy. No person should act on the basis of the contents of this publication, whether as to matters of fact or opinion or other content, without first obtaining specific, independent professional advice in respect of the matters set out in this publication. CONTENTS CONTENTS ........................................................................................................................................... 1 MEDIA SUMMARY ............................................................................................................................. 4 TECHNICAL SUMMARY .................................................................................................................. 5 INTRODUCTION ................................................................................................................................. 7 NEW SOUTH WALES RESEARCH ACTIVITIES ................................................................................... 8 1. Review-Integrated management options for carrot powdery mildew............................. 8 Powdery mildews ....................................................................................................................... 8 Powdery mildews that affect the Apiaceae ................................................................................ 8 Methods for disease assessment and epidemiological studies ................................................. 10 The effect of environment on powdery mildews ...................................................................... 10 Control of powdery mildews .................................................................................................... 11 2. Fungicide field trial 2008/09 .............................................................................................. 14 Introduction .............................................................................................................................. 14 Method ..................................................................................................................................... 14 Results ...................................................................................................................................... 15 Discussion ................................................................................................................................ 19 3. Fungicide field trial 2009/10 .............................................................................................. 21 Introduction .............................................................................................................................. 21 Method ..................................................................................................................................... 21 Results ...................................................................................................................................... 22 Discussion ................................................................................................................................ 22 4. Fungicide field trials 2010/11 ............................................................................................ 23 Introduction .............................................................................................................................. 23 Method ..................................................................................................................................... 23 Results ...................................................................................................................................... 23 Discussion ................................................................................................................................ 26 5. Fungicide field trials 2012 ................................................................................................. 27 Introduction .............................................................................................................................. 27 Methods .................................................................................................................................... 27 Results ...................................................................................................................................... 27 Discussion ................................................................................................................................ 30 6. Greenhouse fungicide trials .............................................................................................. 31 Introduction .............................................................................................................................. 31 Method ..................................................................................................................................... 31 Results ...................................................................................................................................... 32 Discussion ................................................................................................................................ 34 7. Greenhouse trials to examine the effect of powdery mildew on carrot yield ................ 35 Introduction .............................................................................................................................. 35 Method ..................................................................................................................................... 35 Results ...................................................................................................................................... 35 Discussion ................................................................................................................................ 37 8. The host range of Erysiphe heraclei isolated from carrot ............................................... 38 Introduction .............................................................................................................................. 38 Method ..................................................................................................................................... 38 Results ...................................................................................................................................... 39 Discussion ................................................................................................................................ 40 9. The effect of overhead irrigation on powdery mildew of carrot .................................... 41 1 Introduction .............................................................................................................................. 41 Method ..................................................................................................................................... 41 Results ...................................................................................................................................... 42 Discussion ................................................................................................................................ 44 10. Susceptibility of carrot varieties to powdery mildew ................................................. 45 Introduction