Demographic parameters of Diuraphis noxia (Hemiptera: Aphididae) and Hippodamia variegata (Coleoptera: Coccinellidae) recorded in the context of D. noxia infesting resistant and susceptible cultivars of wheat

Abstract

The Russian wheat aphid (RWA), Diuraphis noxia (Kurdjumov), is a serious pest of small grains and can cause losses of about 80% in wheat yields. Chemical control is ineffective against this pest so the combined use of host plant resistance and biological control is seen as a possible better means of controlling this pest. In this study, the potential effect of Omid (resistant) and Sardari (susceptible) cultivars of wheat on life table parameters and daily fecundity of RWA and its predator, Hippodamia variegata (Goeze), were determined using the age-stage two-sex life table theory. The results indicate that the rm, R0, λ, T and GRR of RWA were -0.005 ± 0.01 day-1, 0.9 ± 0.24 offspring per individual, 0.99 ± 0.01 day-1, 21.16 ± 1.79 days and 13.34 ± 2.91 offspring on Omid and 0.159 ± 0.01 day-1, 6.9 ± 0.54 offspring per individual, 1.17 ± 0.01 day-1, 12.14 ± 0.26 days and 12.73 ± 1.22 offspring on Sardari. The corresponding values for H. variegata fed on RWA reared on Omid were 0.24 ± 0.01 day-1, 399.35 ± 53.01 eggs, 1.27 ± 0.01 day-1, 24.67 ± 0.28 days and 544.23 ± 75.86 eggs and on Sardari 0.20 ± 0.006 day-1, 221.56 ± 34.68 eggs, 1.23 ± 0.01 day-1, 26.50 ± 0.41 days and 402.72 ± 67.55, respectively. The resistance of wheat cultivars significantly affected life table parameters and mean fecundity of RWA and H. variegata. Our results indicate that combining both host plant resistance and predators in the integrated pest management of RWA could result in a synergistic effect.