Silk Stage Sweet Corn - Action Thresholds
Action Thresholds for Silk Stage Sweet Corn
Based on Corn Earworm Blacklight Trap Catches (conservative system)
Number of Moths caught |
Silk Spray Schedule |
<1 |
No Spray |
1 |
6 Day |
2 |
5 Day |
3 |
4 Day |
4 |
3 Day |
38 |
2 Day |
Based on Corn Earworm Pheromone Trap Catches
Generally used as a guideline in combination with light trap catch information. Requires use of a wire mesh trap and Hercon CEW pheromone lure placed with the base of the trap at silk height in fresh silking corn. Check traps at 3 times per week throughout the growing season.
Number of Corn Earworm Moths Caught |
|||
Per Day |
Per 5 Days |
Per Week |
Spray Interval |
<0.2 |
<1 |
<1.4 |
No Spray |
0.2 – 0.5 |
1.0 – 2.5 |
1.4 – 3.5 |
6 Day |
0.5 – 1.0 |
2.5 – 5.0 |
3.5 – 7.0 |
5 Day |
1.0 – 13.0 |
5.0 – 65.0 |
7.0 – 91.0 |
4 Day |
>13.0 |
>65.0 |
>91.0 |
3 Day |
In some cases corn earworm catches are very low; however, corn borer and fall armyworm pressure is high. If no sprays are called for CEW, the following spray schedule should be used:
European Corn Borer/Fall Armyworm/Sap beetle |
Spray Schedule |
ECB light trap catch is > 100 per 5 days |
4 Day |
ECB light trap catch is 51-100 per 5 days OR FAW infestations in whorl stage corn is >30% infestation OR Sap Beetle infestation is greater than 10% |
5 Day |
ECB light trap catch is 25 to 50 per 5 days & FAW infestations in whorl stage corn is < 30% infestation & Sap Beetle infestation is < 10% |
6 Day |
ECB light trap catch is < 25 per 5 days & FAW infestations in whorl stage corn is < 30% infestation & Sap Beetle infestation is < 10% |
No Spray |