Delivery of a Diagnostic test pilot scheme for Brassicas and Onions


Summary: Diseases of vegetable brassica and onion crops can be difficult to control in the UK. The reduced numbers of active ingredients and pressure to reduce MRL’s in crops is dictating the number and types of application of fungicides to crops. Disease transmission from oilseed rape during harvest and from unsprayed cauliflower and broccoli crops on to long season crops such as Brussels sprouts is frequent.  Forecasting disease outbreaks in vegetable brassica crops within intensive areas of production where unsprayed and sprayed crops are in the same vicinity is difficult.  The long period between disease infection and symptom appearance which is a characteristic of many of these diseases often leads to diseases becoming well established in crops before the disease is really visible. Additionally many of these diseases are difficult to diagnose correctly and at low levels in crops are difficult to detect and observe. The use of information from detection systems for these diseases has been shown to be very effective in controlling these diseases with the existing approved fungicides. In Scotland Brussels sprout crops are kept virtually free of light leaf spot from planting in May until final harvest in April the following year. This has reduced wastage and chemical applications meaning that growing the crop is more sustainable and efficient than before these systems were used. Disease detection systems can also play a vital role in crop production.

Project code:
FV 456
01 July 2017 - 31 May 2019
AHDB Horticulture
AHDB sector cost:
Total project value:
Project leader:

About this project

Aim: The overall objective of this project is to provide fully validated diagnostic tests for the brassica and onion industry within a commercial setting, and also to provide a vehicle to raise awareness with other growers of the benefits, value, sensitivity and decision support capability of the tests via an AHDB KE program.
1. Utilise existing AHDB antibody cell lines for the named pathogens to provide either an ELISA laboratory service or a LFD diagnostic test for each disease.  Where appropriate, establish new antibody reagents to achieve product performance.

 2. The tests should match the specification and sensitivity of tests previously developed in AHDB funded projects for Mycosphaerella brassicicola, Albugo candida, Pyrenopeziza brassica and Peronospora destructor, in terms of spore thresholds for setting disease risk criteria.

3. Obligate pathogens will require validation using glasshouse raised inoculum for each pathogen and this inoculum will be used in antigen preparations.

4. Tests previously developed for Pyrenopeziza brassicae, Peronospora destructor are linked to an ELISA test format. These should be optimised within the first year so that LFD tests are available for all four tests in 2017.

5. The industry partner (Mologic) will undertake to optimise the provided antibodies (for the named tests) over the 2 years of the project to ensure that they are robust enough to provide a risk rating for the pathogens in LFD usage.

Benefits to Industry
There is considerable scope for benefit from this work in terms of early detection and improved spray timing. Salad onions for example have few active ingredients which can be used to control onion downy mildew. Ultimately, financial benefit will be gained through improved quality and reduced (focussed) pesticide residues.  In year 2 of the project the infield tests will be carried out by the grower / consultant. This will provide the opportunity  for informed disease control measures to be put in place individually.