Degree-day model for adult emergence of the red sunflower seed weevil

Authors: Prasifka, Jarrad; PANTZKE, SHAWNA - North Dakota State University; Rinehart, Joe; FERGUSON, BETH - Former ARS Employee; PRISCHMANN-VOLSETH, DEIRDRE - North Dakota State University

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/4/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The red sunflower seed weevil, Smicronyx fulvis LeConte, is a univoltine seed-feeding pest of cultivated sunflowers. Previous research suggests that peak populations of this pest can be avoided by planting early or early-maturing sunflower hybrids. However, no validated method to predict adult emergence has been available for this pest. Emergence of adult weevils under controlled temperatures in the laboratory allowed estimation of a lower developmental threshold and accumulated degree days for first adult emergence and 50% emergence. When the model was tested in field plots, weevils generally emerged earlier than predicted, likely because measured soil temperatures (in a state-wide weather network) are slightly cooler than what many overwintering weevils experience. This first degree-day model for S. fulvus could be improved with additional emergence (validation) data, but also by using ambient temperatures, which are more accessible than soil temperature data.