淡紫紫孢菌微菌核防治黄瓜根结线虫病及土壤环境对其定殖的影响

微菌核是丝状真菌产生的一种休眠结构,由菌丝特化形成。实验室前期研究发现,淡紫紫孢菌在特定的培养条件下可以产生微菌核,并具有较强的抗逆性和稳定性。本研究通过实验室生测和温室盆栽试验,研究了淡紫紫孢菌微菌核对根结线虫的寄生作用和对黄瓜根结线虫病的防治效果,以及不同土壤条件对生防菌定殖的影响。结果表明,微菌核对根结线虫卵的寄生率随着接种浓度的提高而增加,当浓度为300 MS/mL时寄生率超过50%。黄瓜移栽时接种淡紫紫孢菌微菌核,用量为300个/100 g土时对根结线虫防效为44.7%,在育苗基质中提前接入微菌核可防效提高36.0%。土壤水分、温度和pH值对淡紫紫孢菌微菌核的定殖均有显著影响(P<0.05),含水量过高或过低不利于生防菌增殖,含水量为10%~15%,20 d时淡紫紫孢菌种群数量提高6~9倍。本研究为淡紫紫孢菌微菌核制剂的研发和应用提供了理论指导。

Control of Root-Knot Nematode in Cucumber with Purpureocillium lilacinum Microsclerotia and Effects of Soil Factors on Fungal Colonization

Microsclerotia (MS) is a kind of resistant structure produced by mycelia specializing of some filamentous fungi.In previous studies,we found that Purpureocillium lilacinum could produce microsclerotia under some given culture conditions,which were resistant to adverse environmental stresses.Here,control efficiency of P.lilacinum microsclerotia against root-knot nematode in cucumber and the effects of soil conditions on fungal colonization were investigated in the lab and greenhouse.The results showed that the parasitism rates of the microsclerotia increased with the increase of inoculation concentration.When 300 MS/mL was added,the parasitism rate to nematode eggs was over 50%.The control efficiency of microsclerotia on nematodes in cucumber reached to 44.7% when 300 MS/100 g soil was applied during transplanting.Additionally,it was enhanced by 36.0% with the treatment of microsclerotia in seedling substrates ahead.Soil conditions,such as moisture,temperature and pH had remarkable influence on colonization of P.lilacinum microsclerotia (P<0.05).When soil water contents were 10%-15%,the population densities of the biocontrol fungus increased by 6-9 times compared to those under much high or low moisture.The above results provide theoretical guidance for the development and application of P.lilacinum agents composed of the resistant structure of microsclerotia.