UK/East Anglia: Cabbage stem flea beetle wreaks damage to winter oilseed rape crop

Adult cabbage stem flea beetle (c) Dewar Crop Protection

Adult cabbage stem flea beetle (c) Dewar Crop Protection - Credit: Archant

Beetle damage has contributed to estimated losses of 3.2% of the winter oilseed rape area in England and Scotland, according to a snapshot report commissioned by the levy payers’ organisation Home Grown Cereals Authority (HGCA).

Cabbage stem flea beetle (CSFB) damage has hit the eastern region, with an average of 4.4% of the crop lost, and 2.4% re-drilled, according to a regional survey carried out by the body in September.

Suffolk lost 5% of its crop, with 5% re-drilled, while neighbouring Cambridgeshire lost 8% with 4% redrilled. No crop losses were reported for Norfolk and Essex.

The report, based on the period September 22 to 29, showed an estimated loss across the UK of 3.2%, which is equivalent to 17,000ha. Of the area lost, the report estimated half of the area had been redrilled and half currently left bare.

Cabbage stem flea beetles feed on seedling winter rape in autumn and early winter and can cause considerable damage. They lay their eggs in the soil and newly-hatched larvae enter the plants between October and early April. These tunnel into the leaf stalks and plant stems, before returning to the soil to pupate.

The report suggests significant regional variation in CSFB damage with some growers experiencing significant control issues. This was the case in Hampshire, Bedfordshire and Hertfordshire where over 40% of the winter oilseed rape crop was reported as having damage levels at or above treatment thresholds.

HGCA Research Manager Caroline Nicholls said: “Faced with anecdotal reports of CSFB damage over the early autumn and an immediate lack of industry data on the possible extent of damage, HGCA funded ADAS to co-ordinate and gather evidence from an established network of agronomists covering England and Scotland.

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“The report provides a regionalised ‘snapshot’ estimate of damage in WOSR crops walked in the last week of September.”

Estimates were based on 32,000ha of winter oilseed rape walked by members of the ADAS network which comprised 23 county-level agronomists covering 30 counties.

The area walked was equivalent to 6% of the national area and was scaled up to give a national and regional picture.

The counties with the highest proportion of crops at or above control thresholds were Hampshire (46%), Bedfordshire (43%) and Hertfordshire (43%). Most crop losses were reported in the South East and Eastern counties.

The report Cabbage stem flea beetle snapshot assessment – incidence and severity at end September 2014 was prepared for HGCA by Sarah Wynn, Steve Ellis and Lottie Alves (ADAS UK Ltd)