Study On Dry Rot Of Gladiola (Fusarium Oxysporum Schlecht. Var. Gladioli Mas.)

For better to konw the kind and law's happened in disease of flower plant recent years in Shanghai,the author made a filed survey of major flower plants diseases in Shanghai and a systematic research about dry rot which was a serious disese of gadiola.The purpose of this research was to made foundation for the Organism's habits-rization prevention and cure of Gladiola.The finding of experiments as follows:1.The diseases of major flowering plants and the results of pathogen identification in ShanghaiThe 57 disease were found in 46 species of major flowering plants.Then we proposed disorder directory of flowering plants and the major species of disorder.2.The study of gladiola dry rotThe pathogens isolated of gladiola dry rot were identified and we studied bionomics, the germination conditions of pathogen spores.We confirm the germicidal action and synergistic effect with Trichoderma of fungicide on the pathogen of dry rot of gladiola.The results of experiments as follow:2.1 The identification of pathogens gladiola dry rotThe gladiola dry rot was caused by Fusarium oxysporum Schlecht.var.gladioli Mas. according to appearance of pathogens and related data.2.2 Bionomics of pathogensThe results of biological characteristics indicated that the optimum media for mycelia growth was glucose peptone;the optimum growth medium was PS;the optimum carbon source was fructose;the optimum nitrogen source was cerevisiae fermentum and extractum carnis;the optimum pH was 5～8,and the optimum temperature was 25℃.The effect of light intensity on mycelia growth was not significant.2.3 The study of sprouting condition of pathogens conidium The optimum carbon source and nitrogen source for conidium sprouting were soluble amylum and extractum carnis,respectively.The optimum pH was 5,the optimum temperature for sprouting was 28℃;The effect of light for sprouting was not significant;The causing death temperature of conidium was 52℃.2.3.1 The virulence determination of fungicide to pathogens of gladiola dry rotThe best fungicide which restrained the growth of pathogens was carbendazol,the other was topsin-M.The values of EC₅₀ were 5.567 and 16.18μg·mL^-1,then the values of EC₅₀ of hymexazol was 56.5μg·mL^-1.The best fungicide which restrained the germination of conidiospore pathogens was carbendazol,the other was hymexazol.The values of EC₅₀ were 8.67 and 3.077μg·mL^-1,then the values of EC₅₀ of topsin-M was 124.35μg·mL^-1.2.3.2 The influence of fungicide on trichoderma mycelial growthThe best fungicide in 5 were carbendazol and topsin-M which restrained the growth of Trichoderma mycelial,the values of EC₅₀ were 0.716 and 37.62μg·mL^-1.respectively,the values of EC₅₀ of hymexazol was 698μg·mL^-1,the depressant effect was the poorest.2.3.3 The sensitivity of antagonism trichoderma and Fusarium to several fungicidesWith 5 kinds fungicides of conventional concentration to deal with soil,compared with the control group,the sensitivity of the trichoderma and Fusarium were significant difference(P＜0.05).The mycelial of trichoderma and Fusarium had not grown in the medium by using carbendazol and topsin-M for 7 and 30d,the inhibition rate was 100%. The inhibition rate of hymexazol to Fusarium is also100%,but wasn't influence to trichoderma.2.3.4 The study of Trichoderma joint the hymexazol to prevention and cure the Gladiolus dry rot.Trichoderma combinate with hymexazol,the control effect is better than a separate application results.Trichoderma alone,the inhibition rate was 58%,the hymexazol (200μg/mL) used alone,the inhibition rate was 78%,while the two combined,the inhibition rate was 92%,it was significant difference(P＜0.05).2.3.4 The study of the impact of the mycelial growth and sporulation of fusarium and Trichoderma by used mineral elementIn the concentration of 1000μg/mL and 500μg/mL,copper sulfate,ferric sulfate and boracic acid had inhibitory action to the growth and sporulation of the fusarium and Trichoderma;100μg/mL,only ferric sulfate had strong inhibition to the fusarium,and it can promote the growth and sporulation of the trichoderma.3 The experiments of prevention and cureWithout the pathogen,the germination rate of H6 treatment better than the blank treatment 5%,followed by hymexazol +H6 and CK,the germination rate was equivalency but the difference was not significant.Within the pathogen,the treatment of H6+ hymexazol had highest germination rate,it was 145%,significantly higher than the other treatments,the germination rate of Trichoderma treatment was significantly higher than the pathogen only treatment.The agronomy characters of the gladiola in the treatment of the hymexazol +H6 is better than which in the treatment of hymexazol and H6 only.From the disease incidence rate,carbendazim treatment incidence rate was the lowest it was 15%;followed by the H6+ hymexazol,the incidence rate was 25%,H6+pathogen incidence rate was 60%,the prevention of the treatment of H6+ hymexazol higher than the treatment of H6+pathogen,significantly.So H6 and hymexazol have synergistic effect on prevente the dry rot of gladiola.