Degree days for root, bulb and leafy vegetable pests – 30 May 2011

Enough degree days have accumulated indicating the emergence of 1st generation adults of onion maggot and carrot rust fly in all regions. Also, enough degree days have accumulated indicating egg-laying for carrot weevil, the appearance of tarnished plant bug nymphs and hatching of overwintering eggs of aster leafhopper (except Wellington). Cabbage maggot adults are starting to emerge in Windsor and will start emerging soon in other areas.

Here are the degree days accumulated from April 1st until May 27th-30th, 2011.

Area

Onion Maggot

Cabbage Maggot

Carrot Rust Fly

Carrot Weevil

As of

Bradford/HollandMarsh*

332.1

N/A

382.9

204.8

27/05/2011

Sarnia

338.8

252

389.4

214.8

30/05/2011

London

391.5

298.4

442.6

255.1

30/05/2011

Wellington

308.9

222.8

355.7

182.9

30/05/2011

Windsor

440.4

336.9

496.4

292.5

30/05/2011

Area

Tarnished Plant Bug

Leafhopper

GDD

As of

Bradford/HollandMarsh*

68.2

136.1

284.8

27/05/2011

Sarnia

76.3

148.8

293.3

30/05/2011

London

90.4

177.6

343.7

30/05/2011

Wellington

51.9

116.5

264.6

30/05/2011

Windsor

117.5

213.4

386.1

30/05/2011

* Data provided thanks to Muck Crops Research Station, Department of Plant Agriculture, University of Guelph

 Degree day 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

390

n/a

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