| Plant Size | When to treat |
|---|---|
| Emergence to about 6 inches) | When colonies of 10 to 40 winged adult aphids are present on the majority of the plants 6 inches to boot stage and initial signs of red spotting or yellowing of leaves starting to appear. |
| Six inches through the boot stage) | When majority of plants are infested with rapidly increasing colonies of 50 to 100 aphids, but before leaves begin to die. |
| Boot stage through soft-dough stage) | When small to large colonies totaling more than 500 aphids per plant are present and increasing on the majority of plants; some lower leaves are beginning to become wet and sticky with honeydew; or some leaves are showing yellowing and reddening with a few leaves dying. |
