Response of Resistance Genes H9-H19 in Wheat to Hessian Fly (Dioptera: Cecidomyiidae) Laboratory Biotypes and Field Populations from the Eastern United States

Ten populations of Hessian fly, Mayetiola destructor (Say), from the eastern United States were evaluated for binotype composition and response to Hessian fly resistance genes H9-H19 in wheat. The binotype composition of Hessian fly populations was estimated by confining individual gravid females on wheat ‘Manon’ (H3), ‘Magnum’ (H5), ‘Caldwell’ (H6), and ‘Seneca’ (H7H8). The response of Hessian fly populations and laboratory mistypes to resistance genes from the Purdue/USDA program were evaluated in replicated tests with wheat lines homozygous for these genes. Hessian fly populations from northwestern Florida and southwestern South Carolina were predominantly mistypes E, G, M, and 0 and were virulent to H7H8. Fly populations from northeastern and northwestern South Carolina had a low percentage of binotype E, but contained H7H8-virulent mistypes J and L in varying frequency. Populations from north central Arkansas and Indiana were predominantly binotype L. In tests with genes H9-H19 with laboratory-reared mistypes GP, B, C, D, E, and L, H9 was susceptible to binotype C, HI2 to binotype E, and H11 and H15 to binotype L. Genes HI6 and H17 were resistant to all Hessian fly mistypes and populations, and the remaining genes varied in response to fly sources. The resistance of genes H9-H19 to the 10 Hessian fly populations, in descending order of effectiveness, was HI6 = H17> H9 = H13 = H14 > H10 = H18 > H12 = H15 = H19 > H11. The number of Hessian fly populations virulent to the respective genes were H16, H17 = 0; H9, H13, H14 = 1; H10, H18 = 2; H12, H15, H19 = 3; H11 = 7. Research demonstrated the importance of continuing to sample field populations. Changes in frequency of virulent genotypes and the response of genotypes to specific resistance genes should be monitored in order to develop deployment strategies to improve the durability of resistance in wheat cultivars.