بررسی مقاومت آنتی زنوز چند رقم خیار نسبت به سفید بالک پنبه Bemisia tabaci(Genn)(Hom: Aleyrodidae) در شرایط گلخانه

Bemisia tabaci is one of the most important pests of agricultural products. Several factors such as host plant characteristics affect the population of whiteflies. Due to the short growth period of a generation and high spawning rate, whiteflies management is currently based on frequently applied chemical insecticides. However, excessive use of chemical pesticides has disrupted the natural balance of ecosystems. Thus, there is a need for applying lower risk control methods. One potent strategy for the management of whiteflies is host plant resistance to arthropods. Over cultivation of cucumber in farmlands requires strict management, with emphasizing the importance of selection of resistant genotypes. Therefore, this research investigated antixenosis resistance of some cucumber cultivars cultivated in Iran against this pest under greenhouse conditions. In the free spawning preference experiment, pots having cucumber plants with 2-4 leaves were arranged on a circle with equal distance from the center of the circle in a cage. Then, 50 pairs of male and female mature insects of the same age were released in the center of the cage and after 72 hours, the total number of insects attracted to the plants and eggs laid per unit leaf area were counted and recorded. In the non-free spawning preference experiment, each cultivar of cucumber was placed in separate cages for mature insects and after 72 hours, the number of eggs laid per unit leaf area was calculated for each cultivar. These experiments were conducted separately in a randomized complete block design. The free preference analysis results showed that the effect of different cultivars of cucumber on total insect attraction and free spawning rate is significant. The highest and lowest total number of insects per unit area of leaf were 10.97 and 7.18, respectively on Y353 and Brilliant cultivars. Furthermore, the highest and lowest number of eggs per unit leaf area were 56.29 and 28.13, respectively on Y353 and Brilliant cultivars. Similarly, based on the ANOVA results for non-free spawning preference experiment, there was a significant difference between cucumber cultivars in terms of non-free spawning preference at 1% level and the highest (43.77) and lowest (23.82) number of eggs per unit leaf area were observed on Y353 and brilliant cultivars, respectively. According to the results, the Brilliant cultivar exhibits more antixenosis resistance than other cultivars, thereby gradually downsizing pest population. Considering the outbreak of Bemisia tabaci and over cultivation of cucumber plants in Iran, choosing resistant cultivars is an important preventive measure in whitefly population management.