黄瓜连作土壤高温处理对根结线虫和枯萎病的影响

Effects of high-temperature treatment on root knot nematode and Fusarium wilt in continuous cucumber cropping soil

[目的]设施黄瓜连作导致根结线虫和枯萎病发生普遍且严重,利用夏季温室休闲期高温闷棚是解决上述土传病害安全而有效的途径之一。本试验模拟高温闷棚,研究不同温度处理连作土壤根结线虫和枯萎病的变化,旨在为利用太阳光进行温室高温消毒提供理论支撑。[方法]本试验以连作1~19茬‘津优30’黄瓜品种的土壤为试材,首先探明不同连作茬次黄瓜的根结线虫和枯萎病发生程度以及土壤中二者病原物种群数量的动态变化,然后对发病较重的第17茬连作土壤分别进行45℃、50℃、55℃和60℃的高温处理,最后测定比较不同温度处理后的土壤中病原物数量变化,并对高温处理后的土壤进行栽培试验,测量和比较两种病害的发生程度及植株各项生长指标。[结果]随着黄瓜连作茬次的增加,土壤中根结线虫和枯萎病菌的种群数量均增加,两种病害也逐茬加重,至第17茬两种病害的发病程度及其对应病原物的数量均达最高(或次高)水平;对第17茬黄瓜连作土壤进行45℃~60℃的高温处理,随着温度的升高,土壤中的根结线虫和枯萎病菌的数量均减少,当处理温度达55℃时可完全杀灭土壤中根结线虫,达60℃时可同时杀灭枯萎病菌;用高温处理的连作土壤栽培黄瓜秧苗,其根结线虫病和枯萎病的发生程度均随着处理温度的升高而减轻,当处理土壤的温度达到50℃和60℃以上时,根结线虫病和枯萎病分别被完全控制;另外,用60℃处理的连作土壤定植黄瓜,其后期植株生长指标和壮苗指数也显著优于对照。[结论]土传病害随连作茬次增加而加重主要是缘于土壤中病原物积累,定植前对土壤55℃以上的高温处理,可有效减少乃至完全杀灭土壤中根结线虫和枯萎病菌,从而减轻或杜绝两种病害的发生。

【Objectives】Continuous cucumber cropping causes severe and widespread root knot nematodes and blight.High temperature shed sealing in the summer greenhouse fallow period is one of the safe and effective ways to solve this problem.This study simulated high temperature shacks to treat soil at different temperatures.We monitored changes in root-knot nematodes and blight to provide theoretical support for greenhouse high temperature disinfection with sunlight.【Methods】This experiment used the soil of the continuous cropping 1–19 crops of‘Jinyou30’cucumber variety.First we detected the dynamics of root-knot nematode and Fusarium wilt in different cucumber continuous cropping systems and populations of the two pathogens in soil.Secondly we carried out the high-temperature treatment to the 17^th crop soil at 45℃,50℃,55℃and 60℃.Finally,we measured and compared the changes of the number of pathogens in the soil treated with different temperatures,and carried out cultivation experiments on high temperature treated soil,followed by measuring the incidence of both diseases and the growth indicators of the plants and did comparison.【Results】With more crops of cucumber continuous cropping,the population of root knot nematodes and Fusarium oxysporum in the soil increased gradually.By the 17^th crop,the incidence of both diseases and the number of corresponding pathogens reached the highest(or second highest)level.The 17^th crop soil was treated with the high temperature of 45℃–60℃.With the increase of soil treatment temperature,the number of root knot nematodes and Fusarium wilt was both reduced.When the treatment temperature reached 55℃,root-knot nematodes in soil killed completely,and killed Fusarium oxysporum was killed simultaneously when the temperature reached 60℃.The degree of occurrence of root knot nematode and blight in cucumber seedlings cultivated with high temperature trented soil was also reduced with the increase of treatment temperature.When the soil treatment temperature reached 50℃and above 60℃,root knot nematode and Fusarium wilt was completely controlled.In addition,when the continuous cropping of cucumbers was planted on the soil treated with 60℃,the late plant growth index and seedling index in late growing stages became significantly better than the control.【Conclusions】The increase in soil-borne diseases with continuous cropping was mainly due to the accumulation of pathogens in the soil.High temperature treatment above 55℃to soil before planting can effectively reduce or even completely kill root-knot nematodes and Fusarium oxysporum in soil,thereby reducing or eliminating the occurrence of these diseases.