Two important lady beetle species commonly found in alfalfa fields in Iran are the variegated lady beetle Hippodamia variegata Goeze and the seven spotted lady beetle Coccinella septempunctata (Linnaeus, 1758) (Coleoptera: Coccinellidae). These two species attack many aphid species including the pea aphid, Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae). In this study, the seasonal population changes of A. pisum, H. variegata, C. septempunctata and the parasitoid, Dinocampus coccinellae (Schrank) (Hymenoptera: Braconidae) were studied in alfalfa fields in the 2012 and 2013 seasonal periods. The highest ladybird densities were noted on July 5, 2012 and on September 6, 2013 (17.2±2.8 and 13.4±1.6) individuals per 20 sweeps, respectively. Parasitism rates by D. coccinellae ranged from approximately 3 to 6% in two subsequent years, respectively. Parasitism was higher early in the growing season. Most parasitised ladybirds were females. There was no significant relationship between the temperature and relative humidity with pea aphid populations, although the aphid populations declined during the hot summer period. In contrast, the relationship between temperature and the H. variegata population was significant and positive in both years of the study. It has been shown that these lady beetle species have a major role in reducing the pea aphid populations in alfalfa fields. Due to the relatively low percentage of field parasitism by D. coccinellae, this parasite might not reduce the biocontrol efficiency of lady beetle species.

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 r_m, 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.