Each year brings the threat of sunflower moth damage to producers across the sunflower production belt. These insects can cause significant damage if undetected and left uncontrolled. However, with proper field scouting and timely diagnosis, damage to sunflower fields can be minimized.

Sunflower moths are highly attracted to fields that are beginning to bloom, so scouting and control should take place during the onset of blooming.

"Several areas of the field should be scouted, including the grass margins along side the fields because damage is usually more serious on field margins," says Bruce Due, District Agronomist, Mycogen Seeds.

There are two species of sunflower moth that can be of economic importance to sunflower production: the sunflower head moth and the banded sunflower moth.

Sunflower Head Moth Identification

"The sunflower head moth is a common problem for growers in southern South Dakota and the High Plains area," says Due. "The adult head moth is shiny gray in color, approximately 1/3 inch long and has a cigar shape when at rest. Head moth larvae have alternating dark and light stripes and reach a length of about 3/4 inch when mature. The larvae cause damage by consuming tissue from the face of the sunflower head."

Banded Sunflower Moth Characteristics

According to Due, the banded sunflower moth is commonly found in northern areas of sunflower production. The banded moth can be recognized by the dark band that runs across its wings, which is visible when the pest is at rest. This moth is 1/4 inch long with a 1/2 inch wing span.

"The banded moth can be found from mid-July to mid-September, causing all sunflower fields to be susceptible regardless of planting dates," says Due. "Banded moth larvae are pink to purple in color and can reach a length of 1/3 to 1/2 inch when mature. The larvae damage sunflowers by consuming developing seeds from the face of the sunflower head."

Deciding When to Take Action

According to Due, since there is no effective means of controlling the moth larvae, control of the adult moth must be effective. The timing for sunflower moth control often coincides with efforts to control sunflower seed weevil. Due adds that many times the threshold levels for both pests may be just below the economic injury levels for one pest alone, but the two combined may make control feasible.

"All economic threshold levels are based off an expected return per acre, so in years of very low or very high price levels, the economic threshold levels may be higher or lower respectively," Due concludes. "The economic threshold for sunflowers is about one moth per two plants. When sunflower fields get into late bloom, the danger from this insect pest diminishes."

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