Life Sciences Commons^™

Assessment Of Variation In Susceptibility Of The Fall Armyworm, Spodoptera Frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), To Bacillus Thuringiensis Toxins, Karen Ferreira Da Silva

Department of Entomology: Dissertations, Theses, and Student Research

The fall armyworm, Spodoptera frugiperda, is a polyphagous insect pest affecting multiple crops. Fall armyworm is managed with insecticides and corn hybrids expressing insecticidal proteins derived from Bacillus thuringiensis. The early detection of insect resistance is important for making appropriate management decisions informs IPM and IRM recommendations.

The objective of the first study was to establish baseline susceptibility of fall armyworm populations to the Cry1F Bt insecticidal protein, emphasizing collections from locations where fall armyworm overwinters in the U.S. Fall armyworm neonates were exposed to artificial diet treated with increasing Cry1F concentrations, and mortality and growth inhibition were …

Impact Of Spodoptera Frugiperda Neonate Pretreatment Conditions On Vip3aa19 Insecticidal Protein Activity And Laboratory Bioassay Variation, Karen F. Da Silva, Terence A. Spencer, Carolina Camargo Gil, Blair D. Siegfried, Frederick S. Walters

Department of Entomology: Faculty Publications

BACKGROUND: Variation in response to insecticidal proteins is common upon repetition of insect bioassays. Understanding this variation is a prerequisite to detecting biologically important differences.We tracked neonate Spodoptera frugiperda (J.E. Smith) susceptibility to Vip3Aa19 over 17 generations using standardized bioassay methods. Five larval pretreatment conditions and one bioassay condition were tested to determine whether susceptibility was affected. These included: storage time; prefeeding; storage at reduced temperature; storage at reduced humidity; colony introgression of field-collected individuals. Extremes of photoperiod during the bioassay itself were also examined.

RESULTS: LC₅₀ values for two strains of S. frugiperda varied 6.6-fold or 8.8-fold over …

Utilizing Feed Sequencing To Decrease The Risk Of Porcine Epidemic Diarrhea Virus (Pedv) Cross-Contamination During Feed Manufacturing, L. L. Schumacher, R. A. Cochrane, J. C. Woodworth, C. R. Stark, C. K. Jones, Rodger G. Main, Jianqiang Zhang, Phillip Charles Gauger, S. S. Dritz, M. D. Tokach

Kansas Agricultural Experiment Station Research Reports

Understanding key points of potential cross-contamination during the feed manufacturing process is important to developing efficacious methods to control or prevent transmission of pathogens into swine diets. In this study, an experiment was conducted involving 30 crossbred 10-d-old pigs that were used as a bioassay model for Porcine Epidemic Diarrhea Virus (PEDV) to determine the effects of feed batch sequencing on PEDV cross-contamination and subsequent infectivity. PEDV with a PCR cycle threshold value (Ct) of 11 was uniformly mixed into 4.5 kg of swine diet using a stainless steel bench top mixer validated for mixing efficiency. The inoculated feed was …