نویسندگان
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
The effect of poplar stand density on the spatial distribution pattern of an aphid species, Chaitophorus leucomelas Koch, adult and larvae of poplar flat-headed borer, Melanophila picta Pall., cicadellid leafhoppers, Rhytidodus spp., a cixiid planthopper, Hyalesthes mlokosiewiczi Signoret, predacious ladybirds (Coccinellidae), common lacewing, Chrysoperla carnea (Stephens), aphid flies, Leucopis spp., a parasitoid wasp, Adialytus salicaphis (Fitch) and spiders (Araneae) was investigated in Alborz Research Complex of Karaj during 2002-2003. Experimental treatments included four stand densities (333, 417, 498 and 833 trees/ha) of poplar-alfalfa agroforestry and poplar monoculture (833 trees/ha). Variance to mean ratio and Taylorâs power law were used for determining the spatial distribution patterns of the mentioned arthropods. The results revealed that poplar stand density had different influence on the spatial distribution pattern, index of dispersion (I) and the slope of regression (b) of arthropods, resulting from their biological and ecological traits. Likewise, the spatial distribution of the natural enemies differed from their hosts, which probably resulted from their low population density, slow growth rate and the high searching behavior of natural enemies compared to the pests.
کلیدواژهها [English]
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