Degree days for root, bulb and leafy vegetable pests – 12 June 2012

Thresholds for first generation emergence of onion maggot flies and emergence of tarnished plant bug have been reached for all areas. Cabbage maggot adults are probably past peak flights based on degree days for London, Wellington, Windsor, Thedford and Delhi. Carrot rust fly counts on sticky traps have increased over the last week at the Muck Crops Research Station in the Holland Marsh (where resident populations are present, degree days have indicated emergence of adults in all areas). In Wellington, if resident populations are present, carrot weevil have likely started to lay eggs. In the Holland Marsh, Thedford and Delhi, 90% oviposition by carrot weevil will be completed in ~5 days. The threshold for emergence of local adult leafhoppers has been reached in Windsor and is expected to be reached in other areas over the next 4-5 days.

Here are the degree days accumulated from April 1st until June 12th, 2012.

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

Area

Onion Maggot

Cabbage Maggot

Carrot Rust Fly

Carrot Weevil

As of

Bradford/Holland Marsh*

590.9

n/a

659.5

426.8

12/06/2012

London

628.3

497.8

699.1

442.6

12/06/2012

Wellington

530.7

421.2

593.2

372.9

12/06/2012

Windsor

791.7

649.8

864.6

582.6

12/06/2012

Thedford

611.1

486.6

680.7

430.1

12/06/2012

Delhi

603.4

479.6

674.5

428.3

12/06/2012

Ridgetown

Data not updated since 28 May 2012

 

Area

Tarnished Plant Bug

Leafhopper

GDD

As of

Bradford/Holland Marsh*

204.3

331.9

532.2

12/06/2012

London

213.6

346

561

12/06/2012

Wellington

156.9

281.6

473.2

12/06/2012

Windsor

307.3

460.8

719.9

12/06/2012

Thedford

199.4

331.6

546.4

12/06/2012

Delhi

202.5

333.7

537.4

12/06/2012

Ridgetown

Data not updated since 28 May 2012

 

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

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

 


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