文山州烟草根结线虫发生规律及分布研究

目的]了解文山州旱地土壤根结线虫的分布及发生流行趋势。方法]调查和分析了不同作物土壤中根结线虫的发生密度和分布状况。结果]土壤中根结线虫的发生密度与种植作物种类密切相关,种植烤烟的地块根结线虫密度在烤烟生长季节呈直线上升趋势,与烤烟生育期呈极显著正相关,线虫密度由5月中旬的437.73条/kg干土上升为9月中旬的2 205.93条/kg干土,增幅达403.95%,而种植玉米、辣椒地块根结线虫密度在作物整个生长季节变化较小。文山州文山、广南、麻栗坡、丘北、砚山县旱地土壤中根结线虫数量较多且分布广泛,线虫密度多在200～800条/kg干土。根结线虫在0～100 cm的土壤中均有分布,且主要集中在0～40 cm的耕作层中,40 cm以下随着土层的加深根结线虫数量逐渐减少。结论]为烤烟种植规划、抗病品种选择及根结线虫的防治提供了理论依据。

Occurrence Regularity and Distributions of Tobacco Root-knot Nematodes in Wenshan

Objective] The aim was to understand the occurrence regularity and distributions of tobacco root-knot nematodes in Wenshan.Method]An investigation and analysis of the different crops root knot nematodes was carried out in the soil density and distribution.Result] The density of root-knot nematodes in soil be bound up with plant crops species.In flue-cured tobacco growing season that the density of rootknot nematodes was increasing rapidly in planting flue-cured tobacco field,and positive correlation was found between density of root-knot nematodes and flue-cured tobacco growth season.The density of nematodes from 437.73 individuals /（kg dry soil） in the middle of May increased to 2 205.93 individuals /（kg dry soil） in the middle of September and it,s increase rate was 403.95%,but the density of root-knot nematodes in planting maize and hot pepper fields changed smaller during crops growing season.The results of general investigation for Wenshan,Guangnan,Malipo,Qiubai and Yanshan county indicated that the number of root-knot nematodes of dry land soil was more and distributing wide range,the density of nematodes was mainly 200-800 individuals / kg dry soil.Vertical distribution survey results indicated that the root knot nematodes in 0-100 cm soil all had distribution,and mainly concentrated in the magnetism of 0-40 cm,under 40 cm as the soil layer deepen the density of root knot nematode gradually declined.Conclusion] The research results provide theoretical basis for the planting planing of flue-cured tobacco,selection of resistant varieties and control of root-knot nematodes.