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


2006/2007 SURVEY: SPRING/SUMMER PEST ASSESSMENT 2007

1ST VISIT: GREEN TO YELLOW BUD

    
Unsprayed crops at green to yellow bud were inspected for Cabbage Seed Weevil and Pollen Beetle.
A total of 44 sites will be inspected for this first spring/summer assessment.
 
It is 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 9 1.24 2.7
East 8 0.89 2.04
Midlands & West 13 0.88 2.75
South-East 9 3.90 18.95
South-West 5 0.40 0.95
mean of all 44 sites 1.52 18.95
 
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:1 (2.3%)
Number of sites with more than 10 pollen beetles per plant:1 (2.3%)
Number of sites with more than 5 pollen beetles per plant:1 (2.3%)
 
Site Location Number of sites Cabbage Seed Weevil per plant per site Maximum Cabbage Seed Weevil per plant
North 9 0.00 0.00
East 8 0.01 0.10
Midlands & West 13 0.004 0.05
South-East 9 0.00 0.00
South-West 5 0.00 0.00
mean of all 44 sites 0.0034 0.1
 
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%)

 
Defra Logo delivered to the industry by HGCA
This website was last updated on: 07/08/2008     © Crown Copyright Central Science Laboratory 2007
CSL Logo
All risk predictions published by CropMonitor are provided in good faith and are NOT a substitute for rigorous fieldwalking in combination with advice from BASIS qualified persons. CropMonitor accepts no liability for crop loss or damage resulting from the use of CropMonitor.