Submitted to: Entomological Society of America Annual Meeting North Central Branch
Publication Type: Abstract Only
Publication Acceptance Date: March 20, 2000
Publication Date: N/A
Technical Abstract: The sunflower stem weevil, Cylindrocopturus adspersus (LeConte), is a pest of cultivated sunflower and crop damage has been reported in Colorado, Kansas, and Nebraska since 1994. Weevil larvae construct overwintering chambers at the base of the sunflower stalk that weaken the stem, and if populations are high, can cause plant lodging prior to harvest. The objectives of these studies were to investigate a variety of integrated pest management strategies to reduce weevil numbers in the sunflower stalks and subsequent damage from stalk breakage in the central Plains sunflower production region. The impact of the different methods was evaluated by comparing weevil larval density within the stalks and percent lodging. Between 1997 and 1999 the efficacy of insecticides applied to sunflower foliage, in-furrow, and as seed treatments was investigated. In 1999 selected sunflower hybrids and accessions were evaluated for resistance to stem weevil attack and the effect of four different planting dates on weevil population within the stalks also was compared in both confection and oilseed sunflower. Foliar and in-furrow insecticidal treatments were effective in reducing densities of weevil larvae and lodging, but seed treatment was not. Among the hybrids and accessions evaluated some had about 50% less weevil larvae in the stalks. Weevil numbers within sunflower stalks declined as planting date was delayed. Results showed that a number of management techniques are available for the producer that can reduce weevil densities in the sunflower stalk and subsequent loss due to plant lodging.