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Member Symposium

Plant-Insect Ecosystems

Toward a More Holistic Management of the Western Bean Cutworm, Striacosta albicosta

On-plant movement of western bean cutworm, Striacosta albicosta, in structured and integrated refuges in Ontario, Canada

Wednesday, November 13, 2024

11:25 AM – 11:45 AM MST

Location: Phoenix Convention Center, 131 B, PCC

Presenting Author(s)

Natasha May Weppler (she/her/hers)

PhD Student
University of Guelph
Harriston, Ontario, Canada

Co-Author(s)

AD

Alisson Da Silva

Post-Doctoral Research Associat
University of Nebraska
North Platte, Nebraska
Julie Ann Peterson

Professor
University of Nebraska
North Platte, Nebraska
Yasmine Farhan

Research Associate
University of Guelph
Ridgetown, Ontario, Canada
DH

David Hooker

University of Guelph
Ridgetown, Ontario, Canada
Jocelyn L. Smith

Assistant Professor
University of Guelph
Ridgetown, Ontario, Canada

Western bean cutworm, Striacosta albicosta (Smith; Lepidoptera: Noctuidae), poses a significant threat to corn (Zea mays) and dry beans (Phaseolus vulgaris) in North America. The use of integrated refuges can allow for sub-lethal exposure of the highly mobile S. albicosta larvae to the sole effective Bacillus thuringiensis (Bt) protein, Vip3A, transformed into corn hybrids (Bt corn). This sub-lethal exposure is a key mechanism in driving resistance. S. albicosta larvae exhibit three distinct movement phases as they develop on corn plants: 1) 1^st instars move from egg to tassel, 2) 2-3^rd instars move from tassel to ear, and 3) 4-6^th instars move from ear to ear and plant to plant. Field experiments in 2022-2024 evaluated instar-specific movement in integrated versus structured refuge configurations. Protein-marked larvae were released at the central corn plant in 6 x 9 m plots for each movement phase. For the 2023 and 2024 experiments, larvae were destructively sampled 48 h after release to increase experimental resolution. Results from 2023 suggest structured refuges reduce sub-lethal exposure compared to integrated refuges which may reduce the risk of Vip3A resistance evolution in S. albicosta.