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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Sunflower and Plant Biology Research » Research » Research Project #441399

Research Project: Effects of Planting Date and Hybrid Selection on Damage by the Red Sunflower Seed Weevil

Location: Sunflower and Plant Biology Research

Project Number: 3060-21000-043-038-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Jul 1, 2022
End Date: Jun 30, 2023

(1) Determine whether planting dates within the range permitted by crop insurance can limit damage by the red sunflower seed weevil, and (2) Assess early-maturing sunflower hybrids as an additional tool to reduce risk of losses from insect feeding.

Cultivated sunflowers in North America are exposed to a variety of insect pests adapted to feeding on wild sunflowers. In the primary sunflower-producing states of North Dakota and South Dakota, the red sunflower seed weevil has been the most damaging of these insects, and the recent loss of insecticides (particularly the active ingredient chlorpyrifos) will make weevil management even more challenging. However, there is only one generation of red sunflower seed weevils per year, and female weevils only lay eggs onto developing seeds during the period of sunflower bloom. As a result, both early planting and selection of early-maturing sunflower hybrids could limit the crop’s exposure to red sunflower seed weevils. To determine the effects of planting date on seed weevil damage, sunflowers will be seeded on four different dates that cover the range of permitted planting dates (May 11 – June 15). Each planting will include sunflower hybrids from moderate and ultra-early maturity groups. At crop maturity in the fall, samples of seed from the plots will be analyzed to determine effects of planting date and hybrid selection on the percentage of seed damaged by weevils (and other seed-feeding pests) and oil content. This work is intended to complement the current project Subobjective 2A “Evaluate susceptibility of sunflowers to insect pests and develop genetic markers for host plant resistance traits.” The results should contribute to the sunflower breeding program’s research on early-maturity in sunflower germplasm as a trait that reduces susceptibility to this insect pest.