Biological Characteristics of Ceratocystis fimbriata and Selection of Fungicides in Laboratory

In this trial,the biological characteristics of Ceratocystis fimbriata Ellis et Halsted which was a fungal disease,was studied. The results showed that the suitable carbonsource for Ceratocystis fimbriata Ellis et Halsted growth was lactose,the suitable nitrogen source was yeast extract,and the suitable pH value was 9. Under these three conditions,the colony diameters of Ceratocystis fimbriata Ellis et Halsted were 4. 28,3. 96 and 5. 10 cm,respectively. Mycelium could grow in brightness,darkness and alternating light-dark,and the best in darkness. The lethal temperature of mycelium was 55 ℃,10 min or 58 ℃,5 min. The toxicity of four fungicides to Ceratocystis fimbriata Ellis et Halsted was determined by mycelia growth rate method. The result showed that all 4 fungicides inhibited the mycelia growth of Ceratocystis fimbriata Ellis et Halsted. Of which the 96. 3 % difenoconazole had highest inhibition effect on mycelia growth of Ceratocystis fimbriata Ellis et Halsted,and the value of its EC50was 2. 52; 97 % Topsin-M fungicides had better,and the value of EC50was 7. 21; 97. 6 % tolclofosmethyl and 97 % Flutolanil had the lowest effect,and the values of EC50were 454. 08 and 425. 99,respectively.