Determination of Melanophila Picta Pall. (coleoptera: Buprestidae) Damage Rate in Populus Alba / Medicago Sativa Agroforestry System

ABSTRACT: The poplar flat headed borer is one of important pests of poplar trees. This pest, attacks many poplars in physiological weakness condition and causes considerable damage in nurseries, plantation and wood-lots. This survey carried out in 2008 in order to study the effect of distance and planting system on damage rate of Melanophila picta in poplar/alfalfa agroforestry system in complete block design with 3 replications and 5 treatments (stand distances) of poplar/ alfalfa include, 3×4, 3×6/7, 3×8, 3×10 meter and poplar 3×4 meter using two methods. The first method: In order to estimate of damage rate, 5 levels of bark infestation were determined and infested trees numerated in each plot as fallow. 0=0% (without infestation), 1= 1%-20% (infestation from tree base up to 10cm stem height), 2= 21%-40% (infestation from tree base up to 50 cm stem height), 3= 41%-60% (infestation from tree base up to 150 cm stem height), 4= 61%-80% (condensed infestation from tree base up to 150 cm stem height), 5= 81%-100% (condensed infestation from tree base up to 150cm stem height including side branches). Then damage rate of each stand in plots was numerated. The second method: the number of holes that made by larvae on the bark of infested stands were counted in each plot. Data analysis conducted with SPSS software showed a significant difference among treatments in two methods, the poplar treatment had the most infestation and the most number of holes and 3×10 treatment had the least infestation and the least number of holes.