The Research Of The Cobweb Disease In Hypsizygus Marmoreus

A new disease,never reported in domestic,was found in a Hypsizygus marmoreus cultivation factory in Fujian Province in 2012.The symptom of this disease is some cobweb-like hypha which grow in the root of the stipe of fruitbody at the beginning,and then gradually spread along the stipe to pileus.As the disease proceeds,the mycelia gradual become to cotton wool,while producing a large number of spores,and finally cover the entire fruitbody,and fruitbody gradual deteriorates and rots.In some factory,the disease is serious,spreads rapidly and has caused huge losses.However,the research on this disease is rare.Causes of its occurrence and its transmission route are unclear,which brings great difficulties to the prevention and treatment of the disease.This research focused particularly on the pathogen and tieback verification,strain identification,biological characteristics of pathogen,the situation of disease,the cause of the disease and the disease control methods,the main results are as follows:1.Through tissue separation and single spore separation techniques we got the isolated disease pathogen,denominated as number H.a0001.Strain H.a0001 was confirmed to be pathogen of this disease according to Koch's rules.Through the identification the pathogen from both morphological and molecular biology,we know the pathogen was the Hypomyces aurantius(Pers.)Fuckel(Anamorph was Cladobotryum varium Nees).So we know the disease was cobweb disease.2.We also carried out research on the biological characteristics of Hypomyces aurantius.The results showed that Hypomyces aurantius mycelium could grow varied from 5 to 30? and the optimum temperature is 20?,that the viable pH range is 4.5?10.0 and the optimum pH is 5.5.The mycelial growth rate in acidic condition is faster than in basic condition.The optimum carbon source was glucose;the optimum nitrogen source was peptone.The fungus could not survive in 7%salt environment.Light could inhibite the growth of mycelium.Sporulation characteristics studies showed that the fungus produced the most spores in PDA medium and decreased in Czapek,PMA,PSA,the optimum sporulation carbon and nitrogen sources were glucose and peptone.The result of the spore characteristic research showd that sucrose,glucose and glycine,peptone,acidic condition could promote the germination rate of the spores.Being treated in 50? for 40 min and 55? more than 10 min and more than 15 min UV treatment could inactivate spores.The spores could get through the natural stress conditions with the protect of media,having strong stress resistance.3.We simulated production condition in experimental condition to study the disease occurrence situation.The result showd that although the cobweb disease was fruitbody-particular disease,but could also hurt the mycelia.It could infect Hypsizygus marmoreus in various stages of growth.The spore concentration could affect the disease situation in the stage of mycelium growth.A very small amout of spores invaded,leading to lower yield without disease in fruitbody;A intermediate amount of spores invaded,leading to lower yield but also the disease in fruitbody.Mycelia could not kink into primordia when a large number of spores invaded.The disease could easily occur in high humidity environment,and high tempreture was conducive to spore germination and invasion,however,low tempreture was more easily inducing pathogenesis.In addition,this disease can also harm the other edible mushrooms,such as:Flammulina velutipes,Pleurotus eryngii,Pleurotus geesteranus,and it has a wide host range.4.We did the preliminary exploration of the pathogenesis of this disease on mycelium and fruiting body.Through antagonism experiment,dual culture experiment,inhibition experiment,we did research about Hypomyces aurantius'harmful effects on the mycelium of Hypsizigus marmoreus,the result showd that during the mycelium growth process,Hypomyces aurantius produced some kind of volatile substances to inhibit the mycelium growth of Hypsizigus marmoreus,the volatile substances contain some uncertain substances that will harm the mycelium of Hypsizigus marmoreus,and caused the mycelium of Hypsizigus marmoreus to crack and crush.We did the preliminary purification and activity assay of its broth,the purification result suggestd that crude toxin we got had a certain virulence.Further studies on the classification of the particular active ingredient is needed.5.We did researches on the prevention and treatment method of Hypomyces aurantius.Firstly,the toxicity of nine kinds of familiar fungicides to the hypha and conidium of Hypomyces aurantius,and to the hypha of Hypsizygus marmoreus was determined.The results showed that the provided fungicides had different degrees of inhibition on germination of conidium and hypha of H.aurantius and Hy.marmoreus and that the variance of their inhibition was notable.The optimal fungicide was Fludionil,which had strong inhibitive activity to H.aurantius but was safe to the growth of hypha of Hy.marmoreus.The next two disinfectants were Iprodione and Chlorothalonil.The other six disinfectants including Azoxystrobin,Prochloraz-manganese chloride complex,Carbendazim,Mancozeb,Pyrimethanil,thiophanate-methyl,had toxicity to H.aurantius and hypha of Hy.marmoreus at similar levels.On the other hand,we compared the inhibitory effect of the single and mixed fermentation brothes of Bacillus subtilis,Streptomycetaceae Js-1T,Trichoderma harzianum Tri.sp49,Trichoderma viride Tri.sp53.The result showd the fermentation broth of Streptomycetaceae Js-1T had strong inhibitory effect to the pathogen of cobweb disease,while smaller inhibitory effect to Hypsizygus marmoreus.In addition,we also found mixed fermentation broth of bacilli and trichoderma had stronger inhibitory effect than the single fermentation.This provides a new and very promising biological control method.