Cochylis hospes (Walsingham)
(Source: NDSU Extension Bulletin 25 Sunflower Production Handbook, NDSU Extension Service, September 2007)
Description: The adult has a dark band across the buff or yellowish-tan forewings. The wingspan is about 0.5 inch. Early instar larvae are off-white; late instar larvae are pinkish to red with a brown head capsule. Larvae will be about 0.44 inch at maturity.
Life Cycle: The adults emerge from local overwintering sites rather than migrating long distances. In the northern states the banded moths begin to emerge about mid-July and are present until mid-August. Adults tend to congregate in field margins or adjacent crops during the day and then move into the sunflower crop in the evening. Within a week after emergence, they begin to lay eggs on the outside of the bracts. Eggs may be found through early August and hatch in 5 to 8 days. Larvae develop through five instars and are present in sunflower heads from mid-July to Mid-September. After feeding to maturity, larvae drop to the ground to overwinter.
Damage: Newly hatched larvae move from the bracts (where they feed initially) to the florets of the sunflower head, where they enter open florets to feed. During later stages the larvae tunnel though the base of the floret into the seed and consume the contents. Each larva may destroy 5 to 7 seeds. Silken webbing on the face of the head at maturity indicates the presence of the larvae within the head.
Scouting: Sampling plans have been developed using both adult and egg counts. Adult moth and egg counts should be made when most of the plants are at the stage R-3. A low power magnifier is recommended for egg counts. When monitoring for adult moths during the day (late morning or early afternoon), the moths remain quiet, resting on upper or lower surfaces of the leaves of sunflower plants. When disturbed, they flutter from plant to plant. For details on adult moth and egg scouting and economic thresholds, go to NDSU's Banded Sunflower Moth E-823 (Revised 2019) publication.
Jan Knodel, NDSU Entomologist, has also created a You Tube video in which she walks you through the process of scouting for eggs and determining potential crop loss. Watch it here: Banded Sunflower Moth Egg Scouting
Control: The economic threshold level varies with sunflower prices. When monitoring for adults during daylight hours, one banded moth per 100 plants is a reasonable threshold. For egg counts the threshold level is about 2-3 eggs per six bracts. Chemicals should be applied from the late bud stage (R4) to early bloom (R5.1). Border spraying can be an option. Spraying in early morning or late evening is preferred to minimize the impact of pollinators. Some common control mistakes include: not scouting; waiting too long to spray; and perimeter spraying only and not scouting the interior of the field.
Photos: Visit the Photo Gallery.
Visit the Archive section for a number of articles in The Sunflower magazine regarding insects.
Source: NDSU Extension Bulletin 25 Sunflower Production Handbook, NDSU Extension Service, September 2007 and the High Plains Production Handbook June 2005.