Effects of Bactericides and Ralstonia Solanacearum Avirulent Strain on Phage Survival

The survival of bacteriophages of Ralstonia solanacearum in different environments and the feasibility of combined use of chemical agents and phages in disease control were studied.Three phages P7-1,P1556-1 and P1556-2 were mixed with seven kinds of bactericides and stored at 4℃ and 30℃ respectively,to determine the change of phage titer with time.The results showed that the survival time of the three phages were significantly different in the seven bactericides.The titers of the three phages were zero after mixing with copper hydroxide and copper oxychloride for one month.The resistance to bactericides of the three phages in the order from strong to weak is as follows,P1556-2 > P1556-1> P7-1,and the titer logarithms of P1556-2 were 8.73,7.65,7.93,7.39 and 8.18 in thiazole zinc,zhongshengmycin,chunramycin,oxine-copper and octylamine acetate at 12 months,respectively.Some phages survived from 1-5 months at 30℃,but stayed alive for 6-12 months at 4℃.P1556-2 and P1556-1 had higher titers when they were stored in avirulent strain of R.solanacearum Trp574 than in sterile water.So,the titers were affected by time,temperature,bactericides and phages.Copper hydroxide and copper oxychloride showed obvious inhibition on phages.The survival time of phages can be prolonged at 4℃(low temperature).The avirulent strain of R.solanacearum Trp574 can be used for preservation and culture of P1556-1 and P1556-2.