Submitted to: Journal of Applied Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/18/2010
Publication Date: 12/21/2011
Citation: Landolt, P.J., Guedot, C.N., Zack, R.S. 2011. Spotted cutworm, Xestia c-nigrum (L.) (Lepidoptera: Noctuidae) responses to sex pheromone and blacklight. Journal of Applied Entomology. 135:593-600. DOI:10.1111/j.1439-0418.2010.0157.x. Interpretive Summary: Spotted cutworms are often the most abundant caterpillar damaging potato plants and can infest a wide variety of other crops. Chemical attractants might be used in traps to monitor the presence and abundance of the moth, so that growers can make informed decisions on the timing and necessity of control measures. Researchers at the USDA-ARS Laboratory,Wapato, Washington, in collaboration with scientists at Washington State University, Pullman, determined the isomeric makeup of the spotted cutworm sex pheromone chemistry, developed a lure to use in the field to trap spotted cutworm moths, and determined the times of the season when the moths are active. They found that there are two principal flights of moths, in June and again in August, and that combination of (Z)-5-tetradecenyl acetate and (Z)-7- tetradecenyl acetate was most attractive. However, the spotted cutworm males responded poorly to the pheromone in the August flight, compared to blacklight traps.This information provides potato growers with trapping methods to monitor spotted cutworm moths before cutworms are damaging the crop, and should aid in the timing of monitoring for caterpillars on potato plants and the timing of pesticide applications to improve efficacy of insecticides.
Technical Abstract: Traps baited with the sex pheromone blend of (Z7)- and (Z5)-tetradecenyl acetate captured significant numbers of male spotted cutworm moths, Xestia c-nigrum (L.). Nearly no males were captured in traps baited with (Z7)-tetradecenyl acetate, the major pheromone component. Antennae of spotted cutworm males responded to (Z7)-, (E7)-, (Z5)- and (E5)-tetradecenyl acetate in the laboratory; however there was no response by moths in the field to the E isomers when presented in traps as major and minor components respectively of a binary blend or to the (E7) isomer as a single component. These findings clarify the makeup of a sex attractant that can be used for monitoring X. c-nigrum on agricultural crops in Washington. However, multi-year season-long monitoring of spotted cutworm moths in Yakima Valley apple orchards revealed differential responses to pheromone and blacklight traps. A spring flight period showed a strong moth response to the pheromone compared to blacklight, while a later summer flight period showed a weak moth response to the sex pheromone relative to blacklight. At this time, we do not know which trap type might best indicate spotted cutworm abundance and risk to crops.