The threshold for third generation emergence of onion maggot flies has been reached in Windsor. Degree day accumulations indicate peak of third generation cabbage maggot in the Windsor. The threshold for emergence of second generation carrot rust fly has been reached in all areas, including Wellington. Carrot rust fly activity has increased in the Holland Marsh area.
Report from Michigan: Aster leafhopper numbers have been numbers have been decreasing in the field; however, infectivity remains high.
Watch for thrips on cabbage. There are no thresholds established for thrips on cabbage. Varieties vary in susceptibility to thrips. Over-mature cabbage is a ‘prime’ target for thrips, so try to harvest at proper maturity. Insecticides can help manage thrips applied when field monitoring indicates a need to treat and once the crop reaches cupping stage. Ripcord 400 EC and Up-Cyde 2.5 EC are registered for use on cabbage (do not use on muck soils). Also, Success 480 SC and Entrust 80 W are registered for suppression of thrips on cabbage. Please refer to labels for directions for use.
Here are the degree days accumulated from April 1st until Aug 1st, 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* |
1466.5 |
n/a |
1584.1 |
n/a |
31/07/2012 |
| London |
1536.9 |
1308.4 |
1656.7 |
1204.2 |
31/07/2012 |
| Wellington |
1354.3 |
1146.8 |
1465.8 |
1049.5 |
31/07/2012 |
| Windsor |
1794.3 |
1554.4 |
1916.2 |
1438.2 |
31/07/2012 |
| Thedford |
1490.7 |
1272.2 |
1607.3 |
1168.7 |
31/07/2012 |
| Delhi |
1423.2 |
1209.4 |
1539.3 |
1113.1 |
31/07/2012 |
| 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* |
687.9 |
962.5 |
1358.8 |
31/07/2012 |
| London |
730.2 |
1009.6 |
1420.6 |
31/07/2012 |
| Wellington |
588.5 |
860.2 |
1247.8 |
31/07/2012 |
| Windsor |
917.9 |
1218.4 |
1673.5 |
31/07/2012 |
| Thedford |
703 |
976.2 |
1379 |
31/07/2012 |
| Delhi |
662.3 |
928.5 |
1312.2 |
31/07/2012 |
| 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 |
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 |
