Comparing the oviposition rate of Monosteira unicostata (Mulsant & Rey) on poplar clones in Karaj

Poplar lace bug, Monosteira unicostata (Het.: Tingidae) is one of the most important insect pest of poplars in nurseries and plantations. During 2003-2005, the rate of poplar lace bug’s eggs was studied on 15 native and exotic poplar clones belonging to Populus nigra L., P. alba L., P. deltoides Marsh and also P. x. euramericana (Dode) Guinier in Alborz Research Center of Karaj. In first step, the clones were planted under the randomized complete blocks design with three replications at late March in 2002. Every experimental plot consisted of 16 seedlings. In each plot, four seedlings were evaluated for adult’s oviposition at 15 day intervals starting in early June until mid October. Four leaves of each seedling were randomly sampled and the sum of the eggs was recorded. The average number of the eggs on one cm2 leaf area was calculated. The data were analyzed using SAS software and Duncan test to compare the means. Based on the three year trial period data, there were significant differences (α=1%) among poplar the species and the clones. The clones Populus alba 44.9 & P. alba 58.57 had the highest density of eggs. Followed by, the clones belonging to Populus nigra and also P. xe. Marilandica species showed the highest density as well. In this survey, P. deltoides 77.51, P. deltoides 73.51, P. deltoides 69.55 and also P. x. euramericana 561.41 showed the least number of eggs. With regards to the results achieved at field and in natural conditions, it is obvious that final opinion on introducing clones with permanent resistant to monosteira unicostata needs next complementary studies at controlled conditions.