Integrated decision support tools for management of downy mildew in onions

This project will validate the performance of two types of rotation impact sampler for use in early detection of spores of downy mildew (Peronospora destructor) entering onion crops. This less expensive option for spore trapping will be tested alongside the more sophisticated suction traps for accuracy in trapping spores, whereby spore presence will be identified using the in-field lateral flow device (LFD) specific to P. destructor. The three trap types will be operated at four onion trial locations (provided by AHDB and G’s) over two cropping seasons and data used to examine relative sensitivity in spore detection. In addition, user trials conducted with two commercial growers will evaluate ease of use of the rotation impact sampler and LFD tests as a decision aid for disease management.

The AHDB CropMonitor onion downy mildew module featuring the Milioncast model will be extended to capture results from LFD tests and disease observations, and the four trials sites and two growers will be provided with the updated CropMonitor services to support disease management. All data captured will be analysed to identify a robust spore threshold which can be used as a trigger for disease management action and this metric used to extend the onion downy mildew module to further improve reliability. User feedback questionnaires from all six locations will examine ease of use of the equipment and will inform development of knowledge transfer messages delivered to the industry via a range of media outlets on latest developments in integrated onion downy mildew control. 

Validate rotation impact samplers for use as a more cost effective alternative to suction samplers for robust detection of spores of P. destructor associated with posing an increased infection risk to bulb and salad onion crops 

Define a specific spore threshold for improved decision support for disease management in the crop 

Deliver knowledge transfer to industry