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 |
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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