Originally Submitted: June 3, 2021
We are currently between the second and third generation peak emergences in South Dakota. Seedcorn maggot management must be done before planting, or the populations can be avoided by not planting during times of peak emergence.
Predicting Seedcorn Maggot Emergence Activity With Degree Days
The emergence of seedcorn maggot flies can be estimated by using degree days with a lower developmental threshold of 39 degrees Fahrenheit and an upper developmental threshold of 84 degrees Fahrenheit. Peak emergence occurs at 360 degree days for the overwintering population, 1,080 degree days for the second generation and 1,800 degree days for the third generation.
As a reminder, the equation for degree days is:
(Maximum Daily Temperature + Minimum Daily Temperature) ÷ 2 - The Developmental Threshold
| Accumulated Degree Days |
|
|---|---|
| 360 | Overwintering generation |
| 1080 | Second generation |
| 1800 | Third generation |
| Location |
Since January 1, 2021 |
Emergence Activity |
|---|---|---|
| Buffalo |
|
Second generation |
| Newell |
|
Second generation |
| Rapid City |
|
Second generation |
| Hot Springs |
|
Second generation |
| Lemmon |
|
Second generation |
| Faith |
|
Second generation |
| Cottonwood |
|
Second generation |
| Mission |
|
Second generation |
| Selby |
|
Second generation |
| Gettysburg |
|
Second generation |
| Pierre |
|
Second generation |
| Winner |
|
Second generation |
| Aberdeen |
|
Second generation |
| Huron |
|
Second generation |
| Mitchell |
|
Second generation |
| Tyndall |
|
Second generation |
| Sisseton |
|
Second generation |
| Brookings |
|
Second generation |
| Vermillion |
|
Second generation |
