Effect of irrigation intervals and poplar clones on density of Chrysomela populi (Col. Chrysomelidae) and Melanophila picta (Col. Buprestidae) in Karaj area

In the course of studies carried out during 2008-20011 to determine effects of irrigation intervals on yield of superior poplar clones in Karaj, population densities of two poplar key pests; Chrysomela populi L. and Melanophila picta (PALL.) were compared on the clones. Poplar colons were planted under a split plot design with 3 main treatments (4, 8 and 12 day irrigation intervals) by 3 replication and nine secondary treatments (clones) in Alborz Research Station of Karaj. For sampling of C. populi, four trees from each secondary plot and eight leaves from each tree were selected randomly. Then numbers of different larval instars were counted and the surface of leaves was measured in order to calculate number of this pest in surface unit (cm2). For sampling of M. picta, four trees from each secondary plot were selected and their trunk was covered by sleeve close. Then in next spring the number of emerged insects were recorded and densities in surface unit was determined. Obtained results showed irrigation intervals and poplar clones significantly (α < 0.05) affected densities of C. populi and M. picta. Interaction of irrigation intervals and poplar clones did not effect on density of C. populi, but it influenced on M. picta density, significantly. The highest density of C. populi recorded in 4 and 8 days irrigation intervals and the highest density of M. picta was obtained in 8 and 12 days. Densities of C. populi on P. n. betulifolia and P. d. 69.55 were 0.0340 and 0.0018, respectively. There was significant difference between these clones. The highest density of M. picta was observed on P. e. triplo with 8 and 12 days irrigation intervals. Mean density of M. picta on P. e. triplo was 0.0029 while in 4, 8 and 12 day intervals, the obtained figure were 0.0005, 0.0036 and 0.0045, respectively.