陕西省小麦禾谷孢囊线虫病的新发生地区与田间侵染规律

New Occurrence Regions and Field Infection Regularity of Cereal Cyst Nematode on Wheat in Shaanxi Province

【目的】明确陕西省渭北旱塬区和陕北地区小麦孢囊线虫病(cereal cyst nematode,CCN)发生状况及其田间侵染规律,为陕西省CCN的综合防控提供决策依据。【方法】在小麦孕穗期至灌浆期,采用五点法随机取样、芬萘维克漂浮法(Fenwick)分离孢囊、利用形态学方法鉴定孢囊线虫种类;定点定期取样,利用次氯酸钠-酸性品红法对根系染色,显微镜检查根内线虫虫态与数量。【结果】陕西省渭北旱塬区和陕北地区等24个县(市)小麦的禾谷孢囊线虫病的致病线虫种类为禾谷孢囊线虫(Heterodera avenae Wollenweber)。麟游县的平均孢囊量最高,为32.0个/100 g土,永寿县的平均孢囊量最低,为5.5个/100 g土。调查的陕北地区县市没有发现CCN。冬小麦秋播后,土壤中CCN孢囊孵化后的2龄幼虫(J2)即可侵入根系内。翌年小麦返青,J2幼虫开始侵染,高峰期为3月下旬至4月上旬,4月中旬开始出现3龄幼虫(J3),4月下旬J3开始膨大,5月初在小麦根表可见白色孢囊。【结论】麟游县、永寿县、礼泉县和武功县为CCN新发生地区;CCN在陕西省存在秋播后与返青后2个侵染阶段,1年发生1个世代。

【Objective】The objective of this study is to determine current status of cereal cyst nematode（CCN） on wheat and their field infection regularity in Northern Shaanxi Province and northern areas of Weihe River,and to provide a scientific basis for integrated control of CCN in this area.【Method】 Field surveys of CCN on wheat were performed by sampling with five-point method in field at the booting to milking stages of wheat,isolating CCN cysts with Fenwick flotation method,and identifying CCN species using morphological method.A periodic sampling method in wheat field was used to acquire that the amount and life stage of juvenile（J2） of Heterodera avenae from roots stained by sodium hypochlorite-acid fuchsin solution using a microscope.【Result】 Pathogenic CCN species attacking wheat in twenty-four counties in the two areas was H.avenae.Linyou,Yongshou,Liquan,and Wugong counties were first time to be reported the occurrence of CCN on wheat.On the average,the amount of CCN was the highest with 32.0 cysts/100 g air-dried soil in Linyou County,and the lowest with 5.5 cysts/100 g air-dried soil in Yongshou County.No CCN were found in the investigated wheat fields in the Northern Shaanxi Province.No CCN infection was found in the investigated wheat filed in the Northern Shaanxi Province.Second-stage juvenile（J2） of H.avenae hatching from survival cysts in the soil were detected within young roots of autumn-sown winter wheat.Following the next year,J2 attacking the roots of seedling plants could be observed when wheat started regreening.A peak of J2 infection on wheat emerged at time-span from late March to early April.The third-stage juvenile（J3） generated in middle April and started swelling in late April.Obvious white cysts of H.avenae could be seen on the outside of roots of wheat plants by naked-eyes in early May.【Conclusion】Linyou,Yongshou,Liquan,and Wugong counties were new occurrence areas of CCN on wheat.Two infection periods of CCN on wheat occur after autumn-sown winter wheat and regreening in the following year.One generation of H.avenae took place in growing season of wheat in a year in Shaanxi Province.