Alliums Brassica Vegetables Carrot Insects Leafy Vegetables Pest Management

Root, bulb, leafy and brassica vegetable pest report – 1 Aug 2012

The threshold for third generation emergence of onion maggot flies has been reached in Windsor. Degree day accumulations indicate peak of third generation cabbage maggot in the Windsor. The threshold for emergence of second generation carrot rust fly has been reached in all areas, including Wellington. Carrot rust fly activity has increased in the Holland Marsh area.

Report from Michigan: Aster leafhopper numbers have been numbers have been decreasing in the field; however, infectivity remains high.

Watch for thrips on cabbage. There are no thresholds established for thrips on cabbage. Varieties vary in susceptibility to thrips. Over-mature cabbage is a ‘prime’ target for thrips, so try to harvest at proper maturity. Insecticides can help manage thrips applied when field monitoring indicates a need to treat and once the crop reaches cupping stage. Ripcord 400 EC and Up-Cyde 2.5 EC are registered for use on cabbage (do not use on muck soils). Also, Success 480 SC and Entrust 80 W are registered for suppression of thrips on cabbage. Please refer to labels for directions for use.

Here are the degree days accumulated from April 1st until Aug 1st, 2012.

(These values are provided as guidelines only. Local environments, soil type, field history, etc. may influence activity of these pests.)

Area

Onion Maggot (base 4)

Cabbage Maggot (base 6)

Carrot Rust Fly (base 3)

Carrot Weevil (base 7)

As of

Bradford/Holland Marsh*

1466.5

n/a

1584.1

n/a

31/07/2012

London

1536.9

1308.4

1656.7

1204.2

31/07/2012

Wellington

1354.3

1146.8

1465.8

1049.5

31/07/2012

Windsor

1794.3

1554.4

1916.2

1438.2

31/07/2012

Thedford

1490.7

1272.2

1607.3

1168.7

31/07/2012

Delhi

1423.2

1209.4

1539.3

1113.1

31/07/2012

Ridgetown

Data not updated since 28 May 2012

Area

Tarnished Plant Bug (base 12)

Leafhopper (base 9)

GDD (base 5)

As of

Bradford/Holland Marsh*

687.9

962.5

1358.8

31/07/2012

London

730.2

1009.6

1420.6

31/07/2012

Wellington

588.5

860.2

1247.8

31/07/2012

Windsor

917.9

1218.4

1673.5

31/07/2012

Thedford

703

976.2

1379

31/07/2012

Delhi

662.3

928.5

1312.2

31/07/2012

Ridgetown

Data not updated since 28 May 2012

*Data provided by Muck Crops Research Station, University of Guelph.

Degree day model information for pests 

Degree Days

1st Generation

2nd Generation

3rd Generation

Onion Maggot

210

1025

1772

Cabbage Maggot

314-398

847-960

1446-1604

Carrot Rust Fly

329 – 395

1399-1711

n/a

Carrot Weevil

138 – 156
455 (90% oviposition)

No model available

n/a

Tarnished Plant Bug

40

n/a

n/a

Aster Leafhopper

128 (overwintering egg hatch)

390 (local adult emergence)

n/a

n/a

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