Identification of plant parasitic nematodes associated with crown and roots of walnuts in Hamadan.
2005
Gitti,Mazdosht | Bakhtiari, Mohammad Hassan | Mohammadi, Mohammad Reza | Tanha Mo`afi, Zahra
On the basies of recent findingslow vigore, yellowing and dieback disease of walnut trees is important with economic losses and becoming widespread in Hamadan province. The roll of the nematodes in such complex disease can not be ignored. In order to identification of plant parasitic nematodes associated with roots of walnut trees and nurseries of Hamadan 65 soil and root samples from varius walnut orcards were collected diuring 2002-2004, additional samples from older trees with disease symptones such as low vigore, yellowing, deficiencies and dieback were taken. At laboratory the samples were analyzed and the nematodes were extracted from soil and roots by centrifugal flotation techniqe and killd and transferred to glycerin according to De Grisse,1965. Permanent slides were mounted and specimens were studied with light microscop equipped by drawing tube. In this survey species belong to genera Aphelenchus , Pratylenchs , Helicotylenchus , Ditylenchus , Dorylaimus , Macropostonia , Merlinius and xiphinema were identified. Three important plant parasitic nematodes on walnut roots in HamadanMacropostonia xenoplax , Pratylenchus vulnus and Xiphinema index were studied precisely. M. xenoplax was the most important nematode with population density over 500 nematode per 500 cm 3 soil in 40% of samples. Root lesion nematode P. vulnus was collected frome Asad-abad with high populations extracted in the root lesions and cankers of diseased trees. X. index was collected from Maryanaj, Malayer, Toiserkan, Hamdan and Asad-abad with high populations. These three species are probably important in economic aspects of walnut orchards and nurseries in Hamadan province and it is necessary to perform other projects related to crop losses and control of these nematodes.
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