Identification and Biological Characteristics of Sweet Osmanthus Leaf Blight

A study was made of morphology identification and biological characteristics of sweet osmanthus leaf blight pathogen.The results indicated that its pathogen is Alternaria tenuissima(Fr.) Wiltshire.And the suitable medium was PDBA for mycelia growth,while OLA for sporulation.The best carbon source was starch-sugar for mycelia growth and nucite for sporulation.The best nitrogen source was peptone for mycelia growth and sporulation,while ammonium salt would inhibit the mycelia growth and sporulation.Lack of Mg was disadvantageous for mycelia growth,while lack of K was disadvantageous for sporulation.Adding Zn and Ve was advantageous for mycelia growth,while Cu and Vb2 were advantageous for sporulation.The suitable ranges of temperature and pH value for mycelia growth were 20℃~30℃ and pH5~10 respectively,the optima were 25℃ and pH6,while the ranges of tempetature and pH value for sporulation were 15℃ and 30℃ and pH6~11,and the optima were 30℃ and pH7.The continuous darkness was advantageous for mycelia growth and sporulation.The germination was stimulated by adding of leaf juice of Osmanthus fragrans,sucrose,glucose and beef extract.The ranges of temperature,pH and RH for conidial germination were 23℃~30℃,pH 3~7 and 98%~100%,and the optima were 27℃,pH6 and 98%.And The fungus would be killed if it was at 55℃ for 10 min.