Managing diamondback moth (Plutella xylostella)
This page is designed to provide levy payers with a summary of AHDB funded work along with relevant information from other sources to highlight management options for this pest.
About diamondback moth
Diamondback moth (DBM) is present worldwide wherever its cruciferous host plants grow. Although caterpillars of DMB are a serious pest of field-grown vegetable crops, they can also affect a range of cruciferous crops grown for their ornamental value such as ornamental cabbage and kale, stocks and wallflowers and therefore these crops should also be monitored for signs of the pest.
Latest DBM knowledge for growers
DBM is often described as a 'super-pest' because it has a rapid lifecycle and has been found to be resistant to some insecticides. In 2016, Steve Foster at Rothamsted Research tested three DBM samples for resistance– from Lincolnshire, Suffolk and Scotland. All three samples were resistant to pyrethroids.
Previously considered a migratory pest, recent research from AHDB indicated that DBM could be surviving UK winters. In January 2018, AHDB and Warwick Crop Centre discovered the pest surviving in un-netted swede crops in the south-west of England. Growers are recommended to continue to check the underside of leaves of their crops to monitor for the pest throughout UK winters.... read more.
The AHDB organised a workshop in January 2017 to give Brassica growers, insecticide companies and researchers the opportunity to discuss the situation in 2016, learn lessons and develop strategies to manage similar outbreaks in the future.
The presentations from the diamondBack Workshop event are now available below:
- Click here to view DBM presentation by Andrew Rutherford
- Click here to view DBM presentation by Rosemary Collier
- Click here to view DBM presentation by Charlotte Wainwright
- Click here to view DBM presentation by Steve Foster
The video below shows the migration pattern of DBM, taken from Charlotte Wainwrights presentation at the diamondback moth workshop:
Where pyrethroid-resistant caterpillars are present, growers are likely to get poor control from pyrethroid sprays. It is likely that some of the diamondback moth population will be controlled by natural enemies including parasitoid wasps; these have been found parasitizing diamondback moths at Wellesbourne. Thus use of a selective insecticide would also be beneficial.
— James Rome (@James_Rome1) July 30, 2019
Updated June 2019
120 day authorisation for 'Benevia 10OD' on leafy brassicas
This Emergency Authorisation starts: 2 July 2019
This Emergency Authorisation ends:
• 22 September 2019: for sale and distribution of stocks
• 30 September 2019: for use
• 31 October 2019: for storage and disposal
Keep up to date with the latest DBM pest activity by signing up to receive AHDB Pest Bulletin alerts. These are sent weekly with trap monitoring information to give growers early forecasts based on data collected from various locations around the UK.
You can also monitor DBM activity on the AHDB Pest Bulletin, hosted by Syngenta and the AHDB Pest Blog provides regular updates on pest activity at Wellesbourne and elsewhere - as the information comes in.
AHDB and Warwick Crop Centre are starting to monitor the activity of DBM and silver Y moth on the continent and have set up a web page to summarise the numbers of sightings recorded on web sites in six countries (UK, Belgium, Netherlands, Sweden, Norway, Finland). We will develop this over time.
This information is based on ‘citizen science’ and although it is unwise to make direct comparisons between countries etc. it should be possible to see in ‘real time’ if large numbers build up.
Relevant AHDB literature applicable to diamondback moths includes:
- Factsheet 01/13 'Practical measures to prevent and manage insecticide, fungicide and herbicide resistance for horticultural crops' provides a reminder of best practice management to avoid the development of resistance.
- The AHDB Encyclopaedia of pests and natural enemies of field crops also provides extensive information about DBM and a whole range of other pests.
There is also a key project which is particularly relevant to DBM control, as listed below:
- FV 440 – ‘Lettuce and baby leaf salads: Investigation into control measures for Silver Y moth and caterpillars’. The information in this report, produced this week, is also relevant to DBM.
A DBM lifecycle and further information about the worldwide situation is available at IRAC.