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ARS Home » Midwest Area » Columbia, Missouri » Plant Genetics Research » Research » Publications at this Location » Publication #427086
Research Project: Adaptation of Grain Crops to Varying Environments Including Climates, Stressors, and Human Uses

Location: Plant Genetics Research

Title: Assessing artificial diet and susceptibility of Mexican corn rootworm (Diabrotica virgifera zeae Krysan & Smith) larvae to Gpp34Ab1/Tpp35Ab1 protein

Author
item Ludwick, Dalton
item KERNS, DAVID - Texas A&M University
item Hibbard, Bruce
item HUYNH, MAN - University Of Missouri

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/19/2026
Publication Date: 1/21/2026
Citation: Ludwick, D.C., Kerns, D.L., Hibbard, B.E., Huynh, M.P. 2026. Assessing artificial diet and susceptibility of Mexican corn rootworm (Diabrotica virgifera zeae Krysan & Smith) larvae to Gpp34Ab1/Tpp35Ab1 protein. Pest Management Science. 202. https://doi.org/10.1016/j.cropro.2026.107544.
DOI: https://doi.org/10.1016/j.cropro.2026.107544

Interpretive Summary: Mexican corn rootworm is a subspecies related to the most damaging corn insect pest, western corn rootworm. Despite its prevalence in Texas and relation to western corn rootworm, little is known about Mexican corn rootworm. To understand more about this insect and potential management options, we investigated a population from Texas that had been exposed to commercial practices, including corn expressing Bt proteins toxic to corn rootworms. Experiments included use of an artificial diet designed for western corn rootworm and one of the aforementioned proteins (Gpp34Ab1/Tpp35Ab1) as well as a field trial. Results from the field study suggested corn hybrids expressing older Bt proteins were less effective compared to a newer technology. Additionally, the diet study revealed the Mexican corn rootworm population could consume more protein compared to a susceptible western corn rootworm. We take this information to recommend better practices for growers facing management issues with Mexican corn rootworm.

Technical Abstract: Mexican corn rootworm, Diabrotica virgifera zeae (Krysan & Smith), and western corn rootworm, D. v. virgifera LeConte, are both subspecies of D. virgifera. Knowledge of Mexican corn rootworm is extremely limited and biological and management assumptions for it, including resistance management programs, are based on western corn rootworm. To better understand the degree of similarity to western corn rootworm and potential management options, Mexican corn rootworm from a Texas field population were exposed to different transgenic corn hybrids, reared on an artificial diet designed for western corn rootworm, and tested for their response to varying doses of Gpp34Ab1/Tpp35Ab1. Results from the field test revealed corn hybrids that contained a single Cry protein were less protected than hybrids expressing two or more proteins with the most protection provided by a hybrid expressing two Cry toxins and a double-stranded RNA (dvSnf7). Mexican corn rootworm larvae grew normally on the artificial diet, though they ultimately weighed less when compared to western corn rootworm larvae. Lastly, Mexican corn rootworm larvae from this population were significantly less susceptible to Gpp34Ab1/Tpp35Ab1 than a susceptible western corn rootworm colony, but the insects responded similarly in terms of weight inhibition. Together, the field and diet toxicity data suggest that the Texas field population was resistant to Gpp34Ab1/Tpp35Ab1 and likely the other Cry proteins designed to control corn rootworms. Currently, fields with similar issues to this situation should incorporate a pyramided corn hybrid expressing dsRNA and Bt proteins.