Major oilseed rape pests targeted in CABI Biopesticide project

 

The sight of bright yellow fields of oilseed rape (OSR) covering large areas of the UK at this time of year has long been a sign of spring across rural Britain but in recent years the land area covered by this crop has been dwindling. Where you do still see it, the fields can often have large bare patches – a far cry from the situation less than 10-years ago. So, what has changed?

 

Background: In 2013 neonicotinoids (neonics) were banned from use in agriculture across Europe, largely because of their link to the decline of the honey bee. This means that seeds treated with neonics can no longer be used. Neonicotinoids have been widely used by farmers over the past two decades, so without suitable alternatives, this could be disastrous for the likes of the oilseed rape market. Traditionally, neonics were farmers’ main form of defence against the onslaught of Cabbage Stem Flea Beetle (CSFB), and their removal from the market has hugely reduced the yields of OSR, as infestations become more prevalent.

Challenge: Pyrethroids, synthetic (human-made) pesticides that inhibit the nervous system of insects, are not a long-term or consistent replacement for the loss of neonics as CSFB in the UK is showing increased resistance.

One solution to this problem could be biopesticides, and CABI is working with CHAP to develop and trial a solution that could be brought to market on a large scale.

Tucked away in a CABI laboratory in Egham, Dr Belinda Luke has been working on biopesticides for 23 years. She already has one biopesticide on the market (Green Muscle – a biopesticide for the control of locusts and grasshoppers that is currently being used in the outbreaks in Africa) and another (a biopesticide to control UK storage pests)  is currently going through registration.

Methodology: Using CHAP equipment Dr Luke is developing a biopesticide – a non-chemical pesticide – to help UK farmers kill off pests, such as cabbage stem flea beetles (CSFB) and aphids, which decimate crops up and down the country.

Dr Luke said “The first thing we did was to go through the CABI and CHAP National Reference Collection collection to see if we had a kill. And we found that we did. The fungus showed a good kill certainly on aphids and it also showed promising results on CSFB”.

CSFB and aphids are the curse of every farmer, particularly at the early stage of plant growth, and as the larvae live inside the OSR stem (hence the name) destroying plants at the early stage of growth, they are often not detected until it is too late. The crop is most vulnerable at emergence as beetles feed on and can destroy the growing point. The ban by the EU on the use of neonics means new interventions are now urgently needed. Hence, Dr Luke and her colleagues are excited about their discovery.

Once Dr Luke had established that this fungus could kill the larvae, the next job was to ensure she could get enough spores to make sure there could be a commercially viable product. This is where the CHAP technology came in. Using the CHAP shaker Dr Luke produced a liquid broth (made up of nitrogen and sugars) and poured it onto rice grains. Ten days later she was able to extract the rice from the spores and use these pure spores in a miniature trial.

Using another piece of CHAP equipment Dr Luke sprayed leaves with the fungal spores and then strategically placed aphids to see if they picked up the spores, became infected and died, as they would in their natural environment in the field.

Conclusion: So far the results are looking promising and the fungus appears to be a good producer of spores, although – to ensure that it is commercially viable – more tests are required. CABI and CHAP are now working with commercial companies to develop this further.

CABI and CHAP are leading the way in this essential preliminary work and aim to target other insect pests in the future.  This will create opportunities for commercial companies to go on to produce much-needed environmentally friendly products, giving farmers and growers environmentally friendly solutions to insect pests.

The ultimate aim is to enable growers to increase their yields and meet the growing demand for sustainable produce while reducing chemical inputs and minimising environmental impact.

For more information go to our Fungal Biopesticide Development Lab capability page or visit CABI

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For more information go to our international pest horizon scanning capability page or visit cabi.org

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