Susceptibility of isofamilies of Spodoptera frugiperda (Lepidoptera: Noctuidae) to Cry1Ac and Cry1Fa proteins of Bacillus thuringiensis

• Published in: Southwestern entomologist Vol. 35; no. 3; pp. 409 - 415
• Main Authors: Blanco, Carlos A, Portilla, Maribel, Jurat-Fuentes, Juan Luis, Sánchez, Jaime F, Viteri, Diego, Vega-Aquino, Paulina, Terán-Vargas, Antonio P, Azuara-Domínguez, Ausencio, Lopez, Juan D. Jr, Arias, Renee, Zhu, Yu-Cheng, Lugo-Barrera, David, Jackson, Ryan
• Format: Publication
• Language: English
• Published: 2010
• Subjects: Bacillus thuringiensis; backcrossing; bacterial toxins; Bt corn; Bt cotton; corn; cotton; Cry1Ac protein; Cry1Fa protein; crystal proteins; genetic background; genetic resistance; geographical variation; Gossypium hirsutum; inheritance (genetics); insect pests; insecticidal proteins; insecticide resistance; isofamilies; recessive genes; Spodoptera frugiperda; transgenic plants; Zea mays; Puerto Rico; Mississippi; Texas; Mexico

The fall armyworm, Spodoptera frugiperda (J. E. Smith), is one of the most important insect pests on the American continent. Its control has relied primarily on multiple applications of insecticides that can amount to 1,000 g of active ingredient per hectare on some of approximately 30 crops the insect damages. The use of genetically engineered crops that express Bacillus thuringiensis (Bt) Berliner toxins, Bt-corn, Zee meys L.; and Bt-cotton, Gossypium hirsutum L.; are other ways to control this insect. However, fall armyworm is one of the Lepidoptera species least susceptible to Bt proteins, and a case of high tolerance to Bt-corn has already being reported. We found the susceptibility to Cry1Ac and Cry1Fa proteins of Bt in 133 isofamilies from five regions of three countries was similar to the susceptibility of two Bt-susceptible laboratory colonies to these proteins. Four isofamilies from Puerto Rico were very tolerant to Cry1Fa and not so tolerant to Cry1Ac. Two of the four isofamilies were backcrossed with a Bt-susceptible laboratory colony and their progeny was as susceptible to both Bt proteins as was the Bt-susceptible colony, indicating that resistance to Bt is a recessive trait.