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Sunflower

All Sunflower Content

aerial view of South Dakota farm and surrounding land

Crops

During the growing season, SDSU Extension provides weekly production recommendations.

A sprawling, planted field with young crops emerging

Crop Rotation in Farm Management 

Crop rotation has long been considered an important farm practice. In 2013 producers had to stray from their well thought out crop rotations when the winter wheat crop in South Dakota failed.

Two sunflower seed weevils side-by-side. The weevil on the left is red and the weevil on the right is gray.

Differentiating Two Species of Sunflower Seed Weevils

While scouting sunflower, there are two types of seed weevils that you may encounter. They are the red sunflower seed weevil and the gray sunflower seed weevil. It is possible to observe both of these species on a single sunflower head.

Red-brown colored weevil with bent antennae originating on the elongated mouthparts.

Watch for Red Sunflower Seed Weevils

In South Dakota, sunflower flowering is well underway. That means it is time to start scouting fields for red sunflower seed weevils. During the last two years, red sunflower seed weevil populations have been higher than normal with areas that exceeded the thresholds by as many as 300-500 adults per sunflower head.

Symptoms of three emerging sunflower diseases. From the left: Bacterial Stem Rot, Sclerotinia Basal Rot, and Sunflower Rust.

Bacterial Stem Rot, Sclerotinia Basal Rot and Sunflower Rust Developing in Sunflower

Sunflower scouted this week in Brookings and Kingsbury counties were found with bacterial stem rot, Sclerotinia basal rot and sunflower rust. This area has had plenty of moisture, which favors several diseases to develop in sunflower.

sunflower field

An identification guide to Common Stem Diseases of Sunflower in South Dakota

A guide of common stem diseases in sunflowers in South Dakota

Red-brown colored weevil with bent antennae originating on the elongated mouthparts.

It’s Time to Start Scouting for Red Sunflower Seed Weevils

In South Dakota, sunflower flowering is getting underway. That means it is time to start scouting fields for red sunflower seed weevils.

Small reddish-orange beetles on a green sunflower bud with a larger grey beetle also present.

Identifying Red and Gray Sunflower Seed Weevils

When scouting sunflower, the most observed weevil is the red sunflower seed weevil. However, there are two species of seed weevils that can be present on sunflower heads in South Dakota.

Numerous grasshoppers feeding on a yellow sunflower head.

Watch Sunflowers for Grasshopper Defoliation and Flower Feeding

Grasshoppers continue to be an issue in some areas of South Dakota. The hotspots seem to be along the Missouri River, but it is a reminder that everyone should be monitoring their crops for grasshopper feeding.

Diseased sunflower head, showing sclerotia bodies that have replaced seeds.

Sclerotinia Concerns in Sunflower

Sclerotinia diseases are a concern in sunflowers, because the fungus can infect the plant through the root, mid-stalk or the head. Wet weather and cool temperatures two-to-three weeks prior to and during flowering favor disease development.