Cochylis hospes (Lepidoptera: Tortricidae) damage to male lines varies significantly and inbred susceptibility predicts damage to hybrids

Authors: Prasifka, Jarrad

Submitted to: The Canadian Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/8/2019
Publication Date: 11/1/2019
Citation: Prasifka, J.R. 2019. Cochylis hospes (Lepidoptera: Tortricidae) damage to male lines varies significantly and inbred susceptibility predicts damage to hybrids. The Canadian Entomologist. 151:817-823.
DOI: https://doi.org/10.4039/tce.2019.48

Interpretive Summary: Larvae of the banded sunflower moth, Cochylis hospes, are a primary source of insect damage to seeds of cultivated sunflower, Helianthus annuus, in North America. Field trials were used to evaluate seed damage under natural infestations for panels of publicly-released male lines, publicly-derived hybrids (females crossed to one common male parent), and commercial hybrids over a total of four years. Seed damage to male inbred lines in 2013–2014 ranged from 3–19%. A second male line was statistically similar to RHA 266, the least damaged male. Three commercial hybrids used as checks also received very little seed damage (<3%). Hybrids created by pollinating 15 different female lines with RHA 266 showed 4–14% damage in 2016–2017. Data from female parents explained about 28% of variation in seed damage for the hybrids. Results confirm cultivated sunflower has greater variation in susceptibility to banded sunflower moth than previously believed, and that seed damage to inbred lines provides some predictive power for hybrids. Though breeding for resistance to banded sunflower moth seems possible, it may be too labor-intensive without relating resistance to more easily measurable traits or genetic markers.

Technical Abstract: Larvae of the banded sunflower moth, Cochylis hospes, are a primary source of insect damage to seeds of cultivated sunflower, Helianthus annuus, in North America. Field trials were used to evaluate seed damage under natural infestations for panels of publicly-released male lines, publicly-derived hybrids (females crossed to one common male parent), and commercial hybrids over a total of four years. Seed damage to male inbred lines in 2013–2014 ranged from 3–19%. A second male line was statistically similar to RHA 266, the least damaged male. Three commercial hybrids used as checks also received very little seed damage (<3%). Hybrids created by pollinating 15 different female lines with RHA 266 showed 4–14% damage in 2016–2017. Data from female parents explained about 28% of variation in seed damage for the hybrids. Results confirm cultivated sunflower has greater variation in susceptibility to banded sunflower moth than previously believed, and that seed damage to inbred lines provides some predictive power for hybrids. Though breeding for resistance to banded sunflower moth seems possible, it may be too labor-intensive without relating resistance to more easily measurable traits or genetic markers.