D3425: A universal artificial diet for corn rootworm (Diabrotica spp.) larvae allows ease of rearing and bioassays

Tuesday, November 12, 2024

9:00 AM – 5:00 PM MST

Location: Phoenix Convention Center, Exhibit Hall 6, PCC

Presenting Author(s)

BH

Bruce E. Hibbard

Supervisory Research Entomologist
USDA-ARS
Columbia, Missouri

Co-Author(s)

KH

Khanh-Van Ho

Research Scientist
University of Missouri
Columbia, Missouri
TD

Thu Do

University of Missouri
Columbia, Missouri
RW

Rachael Wolf

University of Missouri
Columbia, Missouri
AP

Adrian J. Pekarcik

Research Entomologist
USDA-ARS
Brookings, South Dakota
DL

Dalton Ludwick (he/him/his)

Research Entomologist
USDA-ARS
Columbia, Missouri
Man P. Huynh (he/him/his)

Senior Research Scientist
University of Missouri
Columbia, Missouri

We identified a single diet formulation that can be used for four Diabrotica species including western (WCR, D. virgifera virgifera), northern (NCR, D. barberi), southern (SCR, D. undecimpunctata howardi), and Mexican corn rootworm (MCR, D. virgifera zeae). The performance of these pests on specialized diets (F9800B diet for SCR, WCRMO-2 diet for WCR, and NCRMO-1 diet for NCR), and a larval diet (F9772 diet) widely used for lepidopteran species. Since there is no diet developed for MCR larvae, WCRMO-2 and F9772 diets were used to rear MCR larvae. After 10 days of rearing, the WCRMO-2 diet yielded better or equal larval growth and development of all four rootworm species compared to other diets. The F9772 diet was the worst diet of all four examined species. For SCR larvae, the WCRMO-2 diet outperformed other diets. Larval fresh weight, percent molt to 2nd instar, and percent molt to 3rd instar on the WCRMO-2 diet were 12-fold, 2.7-fold, and 14-fold increases, respectively compared to that of the F9800B diet. Significantly more SCR larvae survived on the WCRMO-2 diet (98.9%) than on the F9800B diet (90.6%). For MCR larvae, this is the first report to have a diet (the WCRMO-2 diet) capable of rearing this insect species. The WCRMO-2 diet was optimized at pH=5.5, allowing ease of rearing and bioassays. The availability of a universal diet (WCRMO-2 diet) for the four Diabrotica species would facilitate research programs to monitor resistance development and develop new control tactics targeting these important pests.