بررسی اثر ارقام مختلف پنبه بر تراکم جمعیت آفت زنجرک (Asymmetrasca decedens (Hem: Cicadellidae

Differences in the morphological and physiological characteristics of cotton cultivars cause differences in the absorption and damage of pests on these cultivars. The aim of this study was to investigate different cotton cultivars in the densities of population of cotton leafhopper pests in a randomized complete block design with 5 treatments (Khordad, Varamin, red leave okra, Kashmar, Khorshid) and 3 replications. Initially, 24 varieties were randomly selected from each digit and marked with ribbon closure. Sampling was carried out using direct observation method. At each sampling time, the number of insects and lobsters were counted on the back of the 5 leaves from above, middle and bottom. And the average number of insects and nymphs per plant was calculated In order to measure the morphological traits of the cotton plant, the same plants were selected for the direct counting of the poplar population with ribbon. To measure chlorophyll content of leaf, 5 plants per block were selected from each treatment and the fifth leaf of each plant was removed from above. The leaves were placed in chlorophyll meter and average 5 leaves were provided by the machine. To measure the leaf area, 5 plants per block were randomly selected and all leaves of the plant were separated from the petiole and measured with the leaf area measuring device (model: C3100-LI). At the end of the analysis, data was analyzed using SAS software and comparisons of the meanings with Duncan's multi-domain test. The results showed that among the cultivars under study, Kashmar cultivar with the average (12.44 ± 3.57), the highest total number of lizards (total nymph and mature) and okra cultivar with mean (3.33 ± 0.33) The highest mean leaf area was found to be 218.52 cm2 and the highest mean chlorophyll was 40.63spad for the acre red rose. According to the results of this study,the okra cultivar, among the five studied cultivars, recorded the lowest population with the highest chlorophyll average and the highest leaf area, indicating the effect of these two on the resistance of the cotton against the pests This is the number that can be used in the Integrated Cotton Pest Management Program.