Comparison of resistance index of some wheat cultivars to the Sunn pest Eurygaster integriceps (Hemiptera: Scutelleridae)

Field experiments were conducted to comparing of plant resistance index (PRI) in nine wheat cultivars to the sunn pest, Eurygaster integriceps Puton, 1881 in Naghadeh region in 2014. Plants were naturally infected with pest. The number of damaged clusters was used for the study of antixenosis index. To investigate the antibiosis index, second instars nymphal of the pest were reared on plants grown in pots. Mortality percentages of nymphal stage were considered and analyzed as the antibiosis index. To determine the tolerance of cultivars, a field experiment was conducted in a randomized complete block design. Infestation occurred naturally. At the end of the season, the density of 4th and 5th instars nymph was determined on all varieties. Significant differences were observed in all studied traits (p ≤ 0.05). Plant resistance index was determined for all studied cultivars. Cultivars Rasad, Azar 2 and Saysionese were the most resistant cultivars with 8.33, 7.27 and 5.27 amounts of PRI, respectively in comparison to the others. There was a meaningful difference between antixenosis and antibiosis indices (p ≤ 0.01).