Wheat Resistance to the Adult Insect of Sunn Pest, <i>Eurigaster Integriceps</i> Put

Abstract

Sunn pest is one of the most serious pests of wheat and barley in Asia, North Africa and Eastern Europe. Using of resistant cultivars is an effective strategy for Integrated Pest Management (IPM). In order to identify the resistant wheat to sunn pest, 79 Iranian bread and durum wheat cultivars\lines were evaluated for resistance to natural infestations of sunn pest in field conditions using CRD with four replications in Karaj in two cropping seasons. Analysis of variance revealed significant differences among the genotypes for overwintered density of the adult insect and spike damage. Based on density of overwintered adult insect, cultivar Darab 2 with an average of 12.6 insects per m 2 had the highest density and was the most susceptible cultivar to pest damage and the cultivars Marvdasht, M-82-6 and Bezostaya with densities of one insect/m 2 were the most resistant wheat genotypes. The density of overwintered adult insects in oat (resistant check) was zero. Based on the results for spike damage, line S-83-13 with 80 damaged spikes per m 2 and the two cultivars MV17 and Gaspard both with 10 damaged plants per m 2 were identified as the most susceptible and the most resistant wheat genotypes, respectively. Oat showed no damage based on this index. Based on the results of this study, it can be deduced that adult insects decrease grain yield through a reduction to number of grains per spike and number of spikes/area. It was also determined that at this growth stage of the sunn pest, those cultivars, which produce late heading and early maturing, incur less damage, indicating that the sunn pest prefers those cultivars that produce plants with more height than the shorter varieties.