Resistance of various cotton genotypes to the cotton whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae) in Garmsar region

The cotton whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae) is one of the most important cotton pests. To control the whitefly, methods of biological control, chemical, and crop control especially resistant cultivar can be used. In this study, the resistance of different cotton genotypes to the cotton whitefly, B. tabaci was evaluated in field conditions in Garmsar region. For this purpose, the damage of B. tabaci on 10 cultivars was carried out in a split plot design with four replications. The experimental cultivars were including: BC244, SKT133 SAHEL, NSK847, SNK2772, GKTB113, K8802, SKSH249, K8801, and VARAMIN. The results showed that the time of beginning of infestation was different in various cultivars as BC244 and VARAMIN cultivars were infested with the pest sooner than others. At the peak of infestation, the highest population of pest was found on BC244 and VARAMIN and the lowest infestation was in GKTB113 and K8802 cultivars. During sampling at different times, the highest infestation was on BC244 and VARAMIN cultivars, and the least infestation was on K8802, SNK2772 and NSK847 cultivars. By calculating the yield components at harvest time, it was determined that the pest reduced the number and weights of the boll. This decrease was significant in VARAMIN and SAHEL cultivars and the lowest yield reduction was observed in SNK2772. Therefore, based on infestation rate and damage, the most resistant cultivar to the pest is SNK2772 and the most susceptible cultivar is BC244, among the tested cultivars.