A universal artificial diet for corn rootworm (Diabrotica spp.) larval biopesticide assays

Authors: HO, KHANH-VAN - University Of Missouri; Hibbard, Bruce; DO, THU - University Of Missouri; Pekarcik, Adrian; HUYNH, MAN - University Of Missouri

Submitted to: Frontiers in Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/18/2024
Publication Date: 7/2/2024
Citation: Ho, K., Hibbard, B.E., Do, T.T., Pekarcik, A.J., Huynh, M.P. 2024. A universal artificial diet for corn rootworm (Diabrotica spp.) larvae. Frontiers in Insect Science. 4. https://doi.org/10.3389/finsc.2024.1392198.
DOI: https://doi.org/10.3389/finsc.2024.1392198

Interpretive Summary: Diabrotica is a genus of beetles with species including the western (WCR), northern (NCR), and southern corn rootworm (SCR) that are the most important insect pests of corn in the United States. Artificial diet is required to study many pest species. Here, we identified a single diet formulation that can be used to rear larvae of three Diabrotica beetle species including WCR, NCR, and SCR by evaluating the performance of these pests on their respective specialized diets and larval diet widely used for moth larvae. After 10 days of rearing, the WCR diet yielded better or equal larval growth and development of all three rootworm species compared to other diets. For SCR larvae, the WCR diet outperformed other diets. Larval fresh weight, percent molt to 2nd instar, and percent molt to 3rd instar on the WCR diet were 12-fold, 2.7-fold, and 14-fold increases, respectively compared to that of the SCR diet. Significantly more SCR larvae survived on the WCR diet (98.9%) than on the SCR diet (90.6%). The WCR diet supported WCR and NCR larvae equal to the NCR diet and better than other diets. The moth larval diet was the worst diet of all examined species. The availability of a universal diet (the WCRMO-2 diet) for the three Diabrotica species would facilitate research programs to monitor resistance development and develop new control tactics targeting these important pests.

Technical Abstract: We identified a single diet formulation that can be used for three Diabrotica species including southern (SCR), western (WCR), and northern corn rootworm (NCR) by evaluating 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. After 10 days of rearing, the WCRMO-2 diet yielded better or equal larval growth and development of all three rootworm species compared to other diets. 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%). The WCRMO-2 diet supported WCR and NCR larvae equal to the NCRMO-1 diet and better than other diets. The F9772 diet was the worst diet of all examined species. The availability of a universal diet (the WCRMO-2 diet) for the three Diabrotica species would facilitate research programs to monitor resistance development and develop new control tactics targeting these important pests.