Sunflower Beetle The sunflower beetle zygogramma exclamationis feeds only on sunflower. The beetle can be confused with the Colorado potato beetle. The sunflower beetle is smaller, ¼ to ½ inch long, and characterized by three distinct dark stripes. The larvae have a unique 'humpbacked' appearance. This insect was problematic during much of the last two decades in the northern region but has been largely eliminated with insecticide seed treatments. Sunflower beetle larva Life Cycle: There is one generation of the sunflower beetle. Adults overwinter and emerge in the spring and begin to feed. Eggs are laid on the sunflower stem and the underside of leaves. Damage on leaf Damage: The sunflower beetle is a defoliator. Defoliation of the entire early leaves can have a negative yield impact. Later feeding by the larvae can be severe leading to reduced yield and poor seed set. The damage to mature leaves creates a ‘lace-like’ appearance. The sunflower plant can withstand a considerable amount of defoliation without a yield impact. Economic Thresholds: Sunflower can tolerate more damage as the plant matures. One to two adults is the recommended threshold level in the seedling (2 to 6 leaf stage) or 10 to 15 larvae during the later stages or when 25% defoliation occurs in the upper leaves. Scouting Method: The standard X pattern is recommended. Adults and/or larvae should be counted on 20 plants at five different sites within a field. Or plant defoliation should be considered using the same process. Management: Sunflower beetle damage has been largely eliminated by insecticide seed treatments with Cruiser® and Idol®. Most insecticides labeled for sunflower insects include the sunflower beetle and are very effective. Research: There is no additional research being conducted on the sunflower beetle. Photos: Visit the Photo Gallery. For further information, click on the link below. Another resource about Insects can be found in the Archive section of The Sunflower magazine. Source: NDSU Extension Bulletin 25 Sunflower Production Handbook, NDSU Extension Service, September 2007 and the Sunflower Production Guide, Manitoba. Additional Documents NDSU Extension Bulletin 25 - Revised 9/2007 (5592 kb .pdf file) Download Adobe Acrobat Reader
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