Multidimensional approach to formulating a specialized diet for northern corn rootworm larvae

Man P Huynh,B Wade French,Randall P Niedz,Stephen L Lapointe,Thomas A Coudron,Adriano E Pereira,Bruce E Hibbard,Deborah L Finke,Kent S Shelby

doi:10.1038/s41598-019-39709-x

Abstract

The northern corn rootworm (NCR), Diabrotica barberi Smith & Lawrence, is a major pest of maize (Zea mays L.). This pest has developed resistance to insecticides and adapted to crop rotation and may already be in the early stages of adaptation to toxins produced by Bacillus thuringiensis (Bt). Toxicity bioassays using artificial diet have proven to be valuable for monitoring resistance in many species, but no artificial diet has been developed specifically for NCR larvae. Toward this end, we first evaluated known Diabrotica diets to identify a starting media. We then developed a specialized diet for NCR using an iterative approach. Screening designs including 8 diet components were performed to identify the principal nutritional components contributing to multiple developmental parameters (survival, weight, and molting). We then applied mixture designs coupled with response surface modeling to optimize a blend of those components. Finally, we validated an improved NCR diet formulation that supports approximately 97% survival and molting, and a 150% increase in larval weight after 10 days of feeding compared with the best previously published artificial diet. This formulation appears suitable for use in diet bioassays as a tool for evaluating the resistance of NCR populations to insecticides.

Highlights

The northern corn rootworm (NCR), Diabrotica barberi Smith & Lawrence, is a major pest of maize (Zea mays L.)
The Pleau et al diet was improved by Huynh et al.[21], which resulted in a formulation that further increased the weight of western corn rootworm (WCR) larvae and increased both survival and molting after 11 days compared with the first WCR formulation
There was no significant difference between WCRMO-1 and Frontier 9800B

Summary

Introduction

The northern corn rootworm (NCR), Diabrotica barberi Smith & Lawrence, is a major pest of maize (Zea mays L.) This pest has developed resistance to insecticides and adapted to crop rotation and may already be in the early stages of adaptation to toxins produced by Bacillus thuringiensis (Bt). We validated an improved NCR diet formulation that supports approximately 97% survival and molting, and a 150% increase in larval weight after 10 days of feeding compared with the best previously published artificial diet. This formulation appears suitable for use in diet bioassays as a tool for evaluating the resistance of NCR populations to insecticides. This diet was compatible with all current Bt proteins targeting WCR larvae[23]

Methods

Results

Conclusion