Actual yield losses of up 60 to 70 per cent have also been recorded. More precise timing of fungicide applications will help reduce the losses to onion crops.
Addressing this is project FV 3356 Onions - Further development and calibration of detection tests for conidia of onion downy mildew in combination with MORPH forecast model MILONCAST.
Roy Kennedy of the University of Worcester is looking at how downy mildew could be better detected in the field before any visible symptoms are present.
This will allow growers to find out when the best time to spray their crops is and they will be less reliant on using fungicide sprays once the disease has already established on the crop.
A lateral flow device has been developed that will detect the airborne downy mildew spores. Field tests have shown that downy mildew can be detected seven to nine days earlier than symptoms can be seen in the crops. A prototype test has been developed and it is hoped that a lateral device will become available to the industry in the future.
The annual report for FV 356 is available at www.hdc.org.uk.
Date for your diary
15 August - HNS Water Day, East Malling Research, Kent.
Horticultural Development Company
For details on all HDC activity, visit www.hdc.org.uk