Effects of ovipositing height and host tree species on some biological parameters of gypsy moth Lymantria dispar (L.), in Golestan forests (Case Study: Daland Park)

The gypsy moth, Lymantria dispar (L.), is one of the most important pests of forest trees throughout the world. Larval herbivory can result in leaf area reductions, leaves abscission, and eventually, yield quality and quantity losses. The objective of this research was to determine the effects of oviposition height and host tree species on some biological parameters of gypsy moth, including egg clutch size, egg hatching percent, larval body length and mortality percent of first instars. Sampling was carried out in Daland forest park (Infestation foci in Golestan province) during 2008 and 2009. Samples were taken on five oviposition heights (0.5, 1, 1.5, 2, and 2.5 m) on trunk of four common host species including, Zelkova carpinifolia, Parrottia persica, Quecrus castanifolia and Carpinus carpinifolia. A factorial experiment in a randomized design was used to analyze the data and means were compared using Duncan’s multiple range test. Results showed that the oviposition heights significantly affected pest biological parameters, but the effects of host tree species and interacting effects were not significant. The highest survival percent, egg clutch size and body length was observed at oviposition height of 0.5 m on the Parrottia persica species, and the most larval mortality of first instars was recorded at oviposition height of 2.5 m on the Quecrus castanifolia species.