Early-season insects can impact sunflower stand establishment before the crop has a chance to get established. Identifying potential risks ahead of planting and knowing what to watch for during emergence can help reduce stand loss and protect yield potential.
In this installment of the Spring Sunflower Boot Camp, we focus on early-season insect pressure, with an emphasis on cutworms and how growers can manage risk through scouting and timely control.
Cutworms are one of the most common early-season insect pests in sunflower production. They typically feed at or just below the soil surface, cutting plants during or shortly after emergence. This can result in uneven stands and reduced plant populations if not addressed early.
Because cutworms feed primarily at night and remain below the soil surface during the day, they can be difficult to detect without active scouting.
What to watch for early in the season
- Cut or wilted plants shortly after emergence
- Missing plants in patches or scattered areas
- Feeding damage at or just below the soil surface
- Larvae present when digging around damaged plants
Regular scouting during emergence is important to identify issues early and determine if treatment is needed.
Scouting and thresholds
Cutworms can be challenging to monitor due to their feeding behavior, but scouting remains the most effective way to assess pressure.
Checking fields at least twice per week during early emergence can help identify damage and confirm insect presence. A commonly used threshold is one larva per square foot, which can indicate the need for treatment.
Because feeding typically occurs at night, insecticide applications are often most effective when applied in the evening.
Management considerations
- Scout fields regularly during emergence
- Dig around damaged plants to confirm presence
- Monitor populations against treatment thresholds
- Apply insecticide at or just before emergence if needed
- Time applications to align with the feeding activity
Many insecticides labeled for sunflowers provide control of cutworms when applied at the correct timing. However, insecticide seed treatments are not labeled to control cutworms in sunflower, making in-season management decisions important.
Key takeaways:
- Cutworms can reduce stand early in the season
- Damage typically occurs at or below the soil surface
- Scouting during emergence is critical
- Thresholds help guide treatment decisions
- Timely applications improve control
Monitoring early-season insect pressure helps protect stand establishment and supports a more uniform sunflower crop.
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