Root, bulb, leafy and brassica vegetable pest report – 14 August 2012

The threshold for third generation emergence of onion maggot flies has been reached in London and Thedford. Degree day accumulations indicate peak of third generation cabbage maggot in London and Thedford (next couple days for Delhi region, in 7-9 days for Wellington). The threshold for emergence of second generation carrot rust fly has been reached in all areas. Carrot rust fly activity is high in some areas, but has  decreased in some areas of the Holland Marsh.

Here are the degree days accumulated from April 1st until August 14th, 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*

1710.1

n/a

1841.7

n/a

14/08/2012

London

1781.3

1524.8

1915.1

1406.6

14/08/2012

Wellington

1575.7

1340.2

1701.2

1228.9

14/08/2012

Windsor

2047.0

1779.1

2182.9

1648.9

14/08/2012

Thedford

1775.7

1525.2

1908.3

1405.7

14/08/2012

Delhi

1661.3

1419.5

1791.4

1309.2

14/08/2012

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*

819.5

1136.2

1588.4

14/08/2012

London

862.6

1184

1651

14/08/2012

Wellington

697.9

1011.6

1455.2

14/08/2012

Windsor

1058.6

1401.1

1912.2

14/08/2012

Thedford

860

1181.2

1648

14/08/2012

Delhi

788.4

1096.6

1536.3

14/08/2012

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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