Sunflower

All Sunflower Content

National Sunflower Association 2021 Sunflower Survey

Volunteers from private industry and SDSU Extension will soon be visiting South Dakota sunflower fields to participate in the biennial sunflower survey. The survey aims to evaluate yields and production practices along with pest pressure from weeds, insects, diseases and birds.

Three bees. From left: metallic native wild bee, brown native wild bees and bumble bee.

Pollinators Are Active in Sunflower

While scouting sunflowers, it’s hard to not notice the constant buzzing present in the field, which is produced by numerous species of bees. While sunflower varieties grown in the United States were bred for self-fertility, there is evidence that both honey bees and native wild bees can improve pollination.

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

Red and Gray Sunflower Seed Weevil Identification

While scouting sunflower, it’s not uncommon to observe both red and gray sunflower seed weevils on the same developing head. Differentiating these two species isn’t difficult, as there are obvious size and coloration differences.

ALT: Left: Green Plamer amaranth next to a green sunflower. Right: Green plant with green, spiny structure at leaf base.

Palmer Amaranth: Now Is the Time to Scout

South Dakota State University (SDSU) Extension encourages farmers, ranchers and other landowners to start scouting for Palmer amaranth, a weed that has been rapidly spreading north into the United States and is likely to be glyphosate-resistant.

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

Red Sunflower Seed Weevils Are Active

Red sunflower seed weevils are active in South Dakota sunflowers. We noticed that many fields at R5 stages are already being sprayed, but scouting should still continue in those fields after application, and it should begin for fields that will reach the R5 stage within the next week.

a black beetle covered in a white substance

Gray Sunflower Seed Weevils

Gray sunflower seed weevils have been spotted in sunflower fields this week. Although they are a non-economic pest there are times when they can have population outbreaks and reduce sunflower yields.

Zonitis Bilineata on Sunflowers

While scouting sunflower last week we noticed beetles that were present throughout the field on the developing buds. These beetles weren’t feeding on the buds or the bracts that they were often on. So, what were they doing on the sunflowers?

Cream-colored moth with a dark brown band in the middle of its body.

It’s Time To Start Scouting For Banded Sunflower Moths

Sunflowers throughout South Dakota are quickly approaching the R3 growth stage, which means it’s time to start scouting for banded sunflower moths. Banded sunflower moths are capable of reducing yields due to their caterpillars feeding on the bracts, florets and seeds.

Gray beetle with long antennae that are alternating white and black pattern on green leaf petiole.

Dectes Stem Borer May Be More of an Issue During 2021

Dectes stem borers are an annual pest of sunflower in South Dakota. During most years, they do not cause major issues in sunflower. However, we have observed increased issues with this pest during dry years.

Headclipping Weevils in Sunflower

Headclipping weevils have been active in some sunflower fields and in ornamental sunflower throughout South Dakota. Although the headclipping weevil is considered a minor pest of commercial sunflowers, it can cause a lot of problems for individuals trying to maintain sunflowers in their yards and gardens.