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United States Department of Agriculture

Agricultural Research Service

Title: Cold Hardiness and Overwintering of Four Insect Pests of Sunflowers

Authors
item Leopold, Roger
item Rojas, Robert - RETIRED
item Charlet, Laurence

Submitted to: National Entomological Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: September 7, 1999
Publication Date: N/A

Technical Abstract: The biochemical and physiological responses of four insect pests of cultivated sunflowers were examined during overwintering and non- overwintering conditions. The sunflower moth, Homoeosoma electellum (Lepidoptera: Pyralidae), and the sunflower seed weevil, Smicronyx fulvus (Coleoptera: Curculionidae), overwinter in the soil. The sunflower stem weevil, Cylindrocopturus adsperus (Coleoptera: Curculionidae), and the long-horned sunflower stem girdler, Dectes texanus, (Coleoptera: Cerambycidae) overwinter in the sunflower root crowns and tap roots respectively. All insects are freeze intolerant and all accumulate trehalose at the expense of glycogen upon low temperature exposure. The supercooling capacity of 2 of the 4 insects was significantly lowered after cold acclimation, S. fulvus was unaffected and D. texanus was not assayed. Acquiring an internal resistance to innoculative freezing may be the strategy that these insects use to avoid freezing during the winter. S. fulvus gradually builds up a resistance to freezing from September to January with no apparent structural changes in the larval cuticle and in the presence of loosely associated surface nucleators.

Last Modified: 10/25/2014
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