Evaluating western corn rootworm (Coleoptera: Chrysomelidae) emergence and root damage in a seed mix refuge.
Resistance management is essential for maintaining the efficacy and long-term durability of transgenic corn engineered to control western corn rootworm (Diabrotica virgifera virgifera Le Conte). Theoretically, a refuge can be provided by growing susceptible (refuge) plants in either a separate section of the field adjacent to resistant (transgenic) plants, or as a seed mixture. We examined the effects of varying the structure of a 10 and 20% refuge between currently approved structured refuges (block or strip plantings), as well as deploying the refuge within a seed mix, on adult emergence timing and magnitude, root damage and yield. Our 2-yr field study used naturally occurring western corn rootworm populations and included seven treatments: 10 and 20% block refuge, 10 and 20% strip refuge, 10 and 20% seed mix refuge, and 100% refuge. Beetles emerging from refuge corn emerged more synchronously with those emerging from transgenic (Bacillus thuringiensis [Berliner] Bt-RW) corn in seed mix refuges when compared with block refuges. The proportion of beetles emerging from refuge plants was significantly greater in a block and strip refuge structure than in a seed mix refuge. More beetles emerged from Bt-RW corn plants when they were grown as part of a seed mix. We discuss the potential benefits and drawbacks of a seed mix refuge structure in light of these findings.
Murphy
A F
AF
Department of Entomology, Purdue University, 901 West State Street West Lafayette, IN 47907, USA. amckinni@purdue.edu
Ginzel
M D
MD
Krupke
C H
CH
D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics / Q000494:pharmacology; D001517:Coleoptera / Q000502:physiology*; D004731:Endotoxins / Q000235:genetics / Q000494:pharmacology; D005260:Female; D018506:Gene Expression Regulation, Plant; D006460:Hemolysin Proteins / Q000235:genetics / Q000494:pharmacology; D007305:Insecticide Resistance; D008297:Male; D010572:Pest Control, Biological; D018517:Plant Roots / Q000469:parasitology*; D030821:Plants, Genetically Modified; D013997:Time Factors; D003313:Zea mays / Q000235:genetics
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis