effect of host plant on development and reproduction of schizaphis graminum (rondani) (hem.: aphididae)

common wheat, triticum aestivum l. is of the greatest importance among the few crop plants that are grown extensively and for food in iran. among the reported wheat's pests, greenbug schizaphis graminum (rondani) causes severe damage to the crop. because of the adaptation of the aphid to different wheat varieties being varied, this study was designed to focus on the effect of some common wheat varieties in karaj region, namely: pishtaz, shiraz, chamran, mahdavi and marvdasht on the biological parameters pertaining to the greenbug. the experiments were carried out in incubator and under controlled conditions of 22±1?c, 70±10% humidity and 16:8 photoperiodism. the results indicated the longest nympahl period on marvdasht (7.39 days) and the shortest on shiraz variety (6.36 days). the highest number of nymphs was produced on shiraz (46.42) and the lowest on mahdavi (35.72). the parameters rm, r0, ?, t, and dt in relation to the aphid were also assessed and statistically compared on each wheat variety. a comparison of rm as the most important parameter indicated that the highest rm was obtained for shiraz (0.31) while the lowest for mahdavi and marvdasht variety (0.28). the fertility life table parameters revealed that shiraz was the most sensitive to greenbug in comparison with the other varieties. for the calculated parameters, pseudo-replicates were produced through jackknife and bootstrap re-sampling methods, and the results from the two methods were compared.