Antixenosis resistance of one-year-old poplar seedlings of different clones to poplar clearwing moth, Paranthrene tabaniformis Rott. (Lep.: Sessiidae)

Poplar clearwing moth Paranthrene tabaniformis Rott. (Lep.: Sessiidae) is considered as one of the major obstacles affecting the poplar seedlings in nurseries and poplar stands in Iran. In this study, the antixenosis resistance of 12 poplar clones have been studied at Fakhr-Abad Agricultural Research Station in Guilan Province, Iran. This resistance factor was based on the establishment and population density of poplar clearwing moth on the clones in natural conditions. For this purpose, 20 cm-cuttings of the examined species were planted in 9 m2 area plots (three rows with a distance of 1.5 m from each other) at intervals of 20 cm from each other (15 cuttings in each planting row and 45 cuttings in the plot in total) in a randomized complete block design, with three replications. Manuring was performed only once with thrice weeding operations during the growing season (spring 2019). The percentage of infestations by poplar clearwing moth larvae on seedlings and the damage intensity (number of galls formed in each seedling) were recorded. The data were normalized using Kolmogorov-Smirnov test. The results showed a significant differences in the severity of infestation and the number of galls formed among various clones. The Populus euramericana Blanc du poitou and P. x. ITA.199 are reported as the most sensitive clones to the pest by 87.8% and 83.97% of infestation respectively.  Also, P. deltoides 77/51 (known locally as Gildar) and P. x. interamericana by 44.7 % and 51.15% of infestation are considered as the most resistant clones to poplar clearwing moth pest. According to the present findings, the P. x. interamericana and P. deltoides 77/51 clones are suggested for propagation in northern Iran conditions as far as this insect pest is concerned.