Here, I provide a summary of some key points on aphid scouting, but encourage you to review the full document.
- Scouting requires getting into the field and estimating aphid numbers on plants.
- Aphid populations can vary from field to field, so each field being managed should be scouted.
- Estimate aphids from a representative number of plants spread throughout the field.
- Aphid counts should include winged and wingless aphids, but don't count dead aphids or aphid look-alikes.
- Fields should be scouted on a regular basis (about weekly). Rapidly growing populations may need to be scouted more frequently.
- Scouting should continue until R6.5 (pods and leaves begin to yellow), regardless of calendar date.
- Through R5 (seeds developing, but pod cavity not filled), use the economic threshold of an average of 250 aphids per plant AND aphids on more than 80% of plants AND aphid populations increasing.
- Yield loss can occur into early R6 (pod cavity filled by seed). At this stage consider insecticide application if aphid populations are high and plants are experiencing other stress.
- Fields should be scouted after application of a foliar insecticide to monitor for resurgence of the aphid population or outbreak of a secondary pest.