Root, bulb, leafy and brassica vegetable pest report – 18 July 2012

The threshold for second generation emergence of onion maggot flies has been reached in Wellington. Degree day accumulations indicate peak of second generation cabbage maggot in the Wellington. The threshold for emergence of second generation carrot rust fly should be reached in Thedford and London areas in a couple days and the Bradford/Holland Marsh area in ~5 days.

Here are the degree days accumulated from April 1st until July 18th, 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*

1216.5

n/a

1320.1

n/a

17/07/2012

London

1280.5

1080

1386.3

989.8

17/07/2012

Wellington

1121.8

942.3

1219.3

859.0

17/07/2012

Windsor

1512.6

1300.7

1620.5

1198.5

17/07/2012

Thedford

1271.2

1076.7

1375.8

985.2

17/07/2012

Delhi

1168.1

982.3

1270.2

900

17/07/2012

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*

549.9

782.6

999.4

17/07/2012

London

585.8

823.2

1178.2

17/07/2012

Wellington

468.0

697.7

1029.3

17/07/2012

Windsor

748.2

1006.7

1405.8

17/07/2012

Thedford

579.5

816.7

1171.5

17/07/2012

Delhi

519.2

743.4

1071.1

17/07/2012

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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