Study On Pathogen Identification And Biological Characteristics Of The Leaf Spots Of Asplenium Nidus And Solanum Pseudo-capsicumvar Diflorum (Vell.) Bitter

Asplenium nidus belongs to Neottopteris J.Sm..Solanum pseudo-capsicumvar diflorum(Vell.)Bitter belongs to Solanum L..All in one with good edible value,medicinal value,purified value and ornamental value.When investigating flower diseases,the author found that Asplenium nidus and Solanum pseudo-capsicumvar diflorum(Vell.)Bitter are easy to be infected with pathogen.What the worse,it will damage whole plant.Thus,it is extremely urgent for us to determine the etiology.This paper shows the identification of pathogen of leaf spot on Asplenium nidus and Solanum pseudo-capsicumvar diflorum(Vell.)Bitter,studies the biological characteristics of four pathogens,screens the endophytic antagonistic bacterium and tests the antibacterial effect of antagonistic bacterium and pesticides on pathogens.The results are as follows:1.The identification of pathogen of leaf spot on Asplenium nidus and Solanum pseudo-capsicumvar diflorum(Vell.)Bitter: Four pathogenic fungi are Alternaria brassicae(P1),Acremonium alternatum(P2)and Colletotrichum gloeosporioides(B17),Alternaria citrimacularis(B19).2.The biological characteristics of four pathogens of Asplenium nidus and Solanum pseudo-capsicumvar diflorum(Vell.)Bitter: The optimum temperature for mycelia and spores growth is 25?.Mycelia growth is not affected by light,but total darkness is good for sporulation.(1)P1(Alternaria brassicae): The optimum pH value is 6.The optimum humidity for mycelia growth is 95%,the optimum humidity for sporulation is 35%.The optimum carbon and nitrogen source are respectively lactose and yeast extract.Mg SO4 and Na H2PO4 are respectively good for mycelia growth and sporulation.Indole acetic acid is good for mycelia growth,but it would inhibit sporulation.P2(Acremonium alternatum): The optimum p H value for mycelia growth is 5 and p H=8 is good for sporulation.The optimum humidity for mycelia growth is 95%,the optimum humidity for sporulation is 55%.Sucrose and fructose are respectively the optimum carbon source for mycelia growth and sporulation.KNO3,Na H2PO4 and indole butyric acid are good for mycelia growth and peptone,K2HPO4 and VB1 are good for sporulation.(2)B17(Colletotrichum gloeosporioides): when pH value is 6,the mycelia growth rate is the fastest.When p H value is 7,the spores production is the most.The optimum humidity is 95%.The optimum carbon sources are fructose and lactose.The optimum nitrogen source is beef extract and yeast extract.Na H2PO4 and VB6 are good for mycelia growth.K2HPO4 and VB1 are good for sporulation.B19(Alternaria citrimacularis): when p H value is 5,the mycelia growth rate is the fastest.When p H value is 8,the spores production is the most.The optimum humidity is 95%.The optimum carbon sources is xylose.The optimum nitrogen source are yeast extract and peptone.Ca Cl2 and indole acetic acid are good for mycelia growth.Na H2PO4 and VB1 are good for sporulation.3.The antibacterial effects of antagonistic bacterium and pesticides on pathogens of leaf spot: After identifying,the author found that the endophytic antagonistic bacterium,B18-B and B19-B,separated from Solanum pseudo-capsicumvar diflorum(Vell.)Bitter were respectively Pantoea spp and Klebsiella pneumonia ssp ozaenae.The results of bacteriostatic test show that B19-B and bacillus circulans have the best antimicrobial effect.The inhibitory rate of B19-B on B17 is up to 68.4%.The inhibitory rates of B19-B and bacillus circulans on B19 are respectively 62.7% and 63.3%.The inhibitory rate of bacillus circulans on P1 is 76%.The four pesticides have different antibacterial effects on four kinds of pathogens.Thereinto,the difenoconazole is the best.When the concentration of difenoconazole is 200?g/ml,the inhibitory rates on B17 and B19 are respectively up to93.9% and 95.6%.