CROP MONITOR

2007/2008 SURVEY: SPRING/SUMMER PEST ASSESSMENT 2008

1ST VISIT: GREEN TO YELLOW BUD

Unsprayed crops at green to yellow bud will be inspected for Pollen Beetle (and Cabbage Seed Weevil). It is at this stage that the crop is susceptible to economically significant feeding damage from pollen beetles chewing into the buds.

A total of 48 sites will be inspected for this first spring/summer assessment.

At the early flowering growth stage that the Cabbage Seed Weevil begins migrating into the crop. The adults do not cause any economic feeding damage, but will lay their eggs on the developing pods and their larvae feed on the seeds.

Site Location	Number of sites	Pollen beetle per plant per site	Maximum Pollen beetle per plant
North	11	0.67	2.00
East	10	1.56	3.50
Midlands & West	14	0.83	2.60
South-East	7	3.05	10.70
South-West	6	0.58	1.9
mean of all 48 sites		1.24	10.7

Thresholds
Published thresholds are 15 per plant for forward crops and 5 per plant for backward or thin crops.

Number of sites with more than 15 pollen beetles per plant:	0 (0.0%)
Number of sites with more than 10 pollen beetles per plant:	1 (2.1%)
Number of sites with more than 5 pollen beetles per plant:	1 (2.1%)

Site Location	Number of sites	Cabbage Seed Weevil per plant per site	Maximum Cabbage Seed Weevil per plant
North	11	0.00	0.00
East	10	0.00	0.00
Midlands & West	14	0.00	0.00
South-East	7	0.00	0.00
South-West	6	0.00	0.00
mean of all 48 sites		0.00	0.00

Thresholds
Published thresholds are 2 per plant, unless the site has a history of Brassica Pod Midge problems. If this is the case the threshold drops to 1 per plant

If the temperature in the crop is between 11ºC and 15ºC, multiply the mean per plant by 2.26 before considering the threshold value.

Number of sites with more than 2 cabbage seed weevil per plant:	0 (0%)
Number of sites with more than 1 cabbage seed weevil per plant:	0 (0%)

	RAPID ACCESS TO THE LATEST REGIONAL CROP PEST AND DISEASE LEVELS
CropMonitor > Winter Oilseed rape > National Surveys