Action Thresholds for Silk Stage Sweet Corn
Based on Corn Earworm Blacklight Trap Catches (conservative system)
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Number of Moths caught per Seven Days
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Silk Spray Schedule
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<1
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No Spray
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1
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6 Day
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2
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5 Day
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|
3
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4 Day
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4
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3 Day
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38
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2 Day
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| 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. |
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Number of Corn Earworm Moths Caught
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Per Day
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Per 5 Days
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Per Week
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Spray Interval
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<0.2
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<1
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<1.4
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No Spray
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0.2 - 0.5
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1.0 - 2.5
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1.4 - 3.5
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6 Day
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0.5 - 1.0
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2.5 - 5.0
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3.5 - 7.0
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5 Day
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1.0 - 13.0
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5.0 - 65.0
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7.0 - 91.0
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4 Day
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>13.0
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>65.0
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>91.0
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3 Day
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| 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
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| ECB light trap catch is > 100 per 5 days |
4 Day
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| 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
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| 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
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| 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
|