New trials point to stronger control of cabbage stem flea beetle

New trial results could give oilseed rape growers a much-needed new way to strengthen control of cabbage stem flea beetle as resistance continues to weaken the performance of existing insecticides.

Pangaea Biosciences said its Booster technology sharply improved the performance of commonly used insecticides in laboratory tests, although independent UK field evidence has not yet been provided.

Cabbage stem flea beetle remains a major threat during crop establishment, when young oilseed rape plants are particularly vulnerable.

The withdrawal of neonicotinoid seed treatments left growers more reliant on foliar insecticides, while resistance and a reduced choice of chemistry have made consistent control harder to achieve.

Pangaea describes Booster as a patented technology designed to support the performance of existing insecticides where resistance may be limiting their effectiveness.

Trials released by the company tested the product alongside insecticides used against cabbage stem flea beetle, cabbage stem weevil and cabbage root fly.

In laboratory tests against cabbage stem flea beetle, cypermethrin applied alone achieved mortality of between 20% and 60%, depending on the insect population tested.

Deltamethrin used alone recorded mortality of between 40% and 80%.

When Booster was added, mortality increased to between 90% and 100% with cypermethrin and between 95% and 100% with deltamethrin.

The trial report said adding Booster “dramatically increased efficacy” across all cabbage stem flea beetle populations tested.

Pangaea said the results indicated that the technology could help insecticides perform more effectively against populations affected by metabolic resistance.

However, the information released did not include full trial protocols, sample sizes, replication, application rates or statistical analysis.

It also did not identify who conducted the work or state whether the findings had been independently reviewed or published in a scientific journal.

Separate commercial observations have been reported by Czech distributor Ag Novachem, although supporting field protocols and independent analysis were not supplied.

The business began testing Booster in 2021 after reporting a decline in pyrethroid performance in oilseed rape. It started selling the product commercially in 2022.

Ag Novachem founder Jan Hrbácek said: “We could see that the efficacy of pyrethroids was falling, particularly in oilseed rape.

“They are among the most widely used insecticides because they are familiar, affordable and practical, but growers were seeing weaker results.

“It was clear that resistance had become a major issue and that farmers needed a way to bring performance back into their programmes.”

Mr Hrbácek said laboratory efficacy reached 100%, while field performance consistently reached at least 80%.

“In the laboratory, we saw 100% efficacy, and in the field, we are consistently seeing at least 80% efficacy,” he said.

“Before Booster, performance was often below 50%.”

Those figures were supplied by the distributor and were not accompanied by details of plot design, untreated controls or independent verification.

The trials also reported stronger performance against cabbage stem weevil.

Treatments combining Booster with cypermethrin or deltamethrin generally achieved mortality of between 95% and 100%, compared with lower and more variable results from the insecticides alone.

Chlorantraniliprole achieved mortality of between 50% and 60% when used alone, rising to between 90% and 95% when combined with Booster.

The report said the technology could improve insecticide performance against pest populations showing reduced susceptibility.

Field experiments were also carried out against cabbage root fly in oilseed rape.

Pangaea said cypermethrin and deltamethrin provided only partial protection nine days after treatment, while adding Booster reduced observed damage by about half.

The information supplied did not include the original damage scores or statistical analysis for those experiments.

Pangaea chief executive Nick Gooch said oilseed rape was returning to the attention of growers, but cabbage stem flea beetle continued to undermine confidence in the crop.

“The loss of neonicotinoid seed treatments changed the risk profile of OSR production,” he said.

“Growers have been left trying to manage CSFB with fewer options, while resistance has made standard insecticide programmes less reliable.”

Mr Gooch said Booster was intended to improve the performance of existing insecticides rather than encourage additional applications.

“This is not about presenting Pangaea Booster™ as a silver bullet,” he said.

“It is about giving growers, agronomists and distributors a stronger tool for a crop that has been under pressure for too long.”

He warned that poor control during establishment could lead to crop loss, re-drilling, reduced yield potential and growers losing confidence in oilseed rape.

Pangaea said the findings supported Booster’s potential as a resistance-management aid across the UK and Europe.