Table 2. Key Degree
Day Thresholds for Field Crop Insect Management
| Pest Species
|
Accumulative
Degree Days Required to Reach Stage |
Base
Thresholds |
| European
corn borer |
|
54.5ºF |
| First Generation
|
|
|
| Flight |
Beginning - 378
Peak -558
Termination - 918 |
|
| Scout for 1st generation injury
symptoms |
648
|
|
| Implement control |
734 |
|
| Second Generation |
|
|
| Flight |
Beginning - 1279
Peak - 1459
Termination - 1819 |
|
| Egg mass scouting |
Between - 1350 and 1459 |
|
| Implement control |
1459 |
|
| Black
cutworm |
|
50ºF |
| Begin watching for plant clipping
|
300 after peak capture in
pheromone trap |
|
| Stalk Borer
|
|
41ºF |
| Scout for evidence of stalk borer
in grass (look for dead stems and larvae) |
1,300 to 1,400 |
|
| Make a decision to treat a field
for control of larvae |
1,400 to 1,700 |
|
| Spray egg-laying sites |
575 to 750 |
|
| Corn
Rootworm |
|
53ºF |
| Time post-emergence treatments
|
380 to 474 |
|
| Period for adult scouting |
1,253 to 2,253 |
|
| Alfalfa
Weevil |
|
48ºF |
| Initiate scouting |
300 to 500 |
|
| Seed Corn
Maggot |
|
|
| Safe planting time |
450 DD after plowdown |
40ºF |
|
