D3142: Survival of an ear-feeding caterpillar, western bean cutworm (Striacosta albicosta), in integrated vs. structured refuge of Vip3A-expressing Bt maize

Monday, November 14, 2022

9:00 AM – 6:30 PM PT

Location: West Exhibit Hall A

Presenting Author(s)

Nour Elhouda Zarrougui

J1 short-term scholar
University of Nebraska
North Platte, Nebraska

Co-Author(s)

Nour Elhouda Zarrougui

J1 short-term scholar
University of Nebraska
North Platte, Nebraska
Alisson S. Santana

PhD Student
São Paulo State University
Botucatu, Brazil
Julie Ann Peterson

Associate Professor
University of Nebraska
North Platte, Nebraska

Field-evolved resistance to transgenic Bt crops is a challenge to global food security and sustainable production. Western bean cutworm (Striacosta albicosta) has evolved resistance to Cry1F, leaving Vip3A the only effective Bt technology for this pest. Most Vip3A traits are integrated with 5% non-Bt refuge seed. However, seed blends can impact the efficacy of resistance management due to cross-pollination and larval movement.Considering this, our objective is to characterize the relative survival of S. albicosta in Vip3A blended refuges compared with pure stands of Vip3A and non-Bt maize. To achieve this goal, a field study was conducted and each of the three tratments was replicated five times in a randomized complete block design. All plots were scouted during the egg laying and larval period (July-August 2022), to record the presence and deveopmental stage of egg masses and larvae. Ear bags were placed over the primary ear of 30 naturally infested ears per plot. Plots that showed less than 10% of natural infestation were artificially infested with 4th instar larvae. All ear bags were inspected frequently, and the number of recovered larvae was recorded. The size of recovered larvae was measured and ear feeding damage was assessed. The plants were gene-checked using enzyme-linked immunosorbent assay (ELISA). Our results can increase understanding of the dynamics within blended and structured refuges that may impact threats of S. albicosta resistance to Vip3A.