Entomology 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 …

Effect Of Maize Lines On Larval Fitness Costs Of Cry1f Resistance In The European Corn Borer (Lepidoptera: Crambidae), Jennifer L. Petzold-Maxwell, Blair D. Siegfried, Richard L. Hellmich, Craig A. Abel, Brad S. Coates, Terrence A. Spencer, Aaron J. Gassmann

Department of Entomology: Faculty Publications

Crops producing insecticidal toxins from the bacterium Bacillus thuringiensis (Bt) are widely planted and enable management of key insect pests while reducing the use of conventional insecticides. However, the evolution of Bt resistance could diminish these benefits. Fitness costs of Bt resistance occur in the absence of Bt toxin when individuals with resistance alleles show a reduction in fitness relative to susceptible individuals, and they can delay the evolution of resistance. Ecological factors including host-plant variety can affect the magnitude of fitness costs, and consequently, the degree to which fitness costs delay resistance. In this study, we measured fitness costs …

Characterization Of Resistance To The Cry1f Toxin From Bacillus Thuringiensis In Resistant Fall Armyworm, Spodoptera Frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) From Puerto Rico, Ana Maria Velez

Department of Entomology: Dissertations, Theses, and Student Research

Transgenic corn expressing Cry1F protein from Bacillus thuringiensis Berliner has been registered for Spodoptera frugiperda control since 2003. Unexpected damage to Cry1F corn was reported in 2006 in Puerto Rico and Cry1F resistance in S. frugiperda was documented. The inheritance of Cry1F resistance was characterized in a S. frugiperda resistant strain from Puerto Rico which displayed >387-fold resistance to Cry1F. Concentration-response bioassays of reciprocal crosses of resistant and susceptible parental populations indicated that resistance is recessive and autosomal. Bioassays of the backcross of the F₁ generation crossed with the resistant parental strain suggest that a single locus is responsible …

Inheritance Of Cry1f Resistance, Crossresistance And Frequency Of Resistant Alleles In Spodoptera Frugiperda (Lepidoptera: Noctuidae), A. M. Vélez, T. A. Spencer, A. P. Alves, D. Moellenbeck, R. L. Meagher, H. Chirakkal, B. D. Siegfried

Department of Entomology: Faculty Publications

Transgenic maize, Zea maize L., expressing the Cry1F protein from Bacillus thuringiensis has been registered for Spodoptera frugiperda ( J. E. Smith) control since 2003. Unexpected damage to Cry1F maize was reported in 2006 in Puerto Rico and Cry1F resistance in S. frugiperda was documented. The inheritance of Cry1F resistance was characterized in a S. frugiperda resistant strain originating from Puerto Rico, which displayed >289-fold resistance to purified Cry1F. Concentration–response bioassays of reciprocal crosses of resistant and susceptible parental populations indicated that resistance is recessive and autosomal. Bioassays of the backcross of the F1 generation crossed with the resistant parental …