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
per Seven Days

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