We tested the inhibitory effects of five kinds of bacteria on pathogenic fungi causing epiphysis. The results showed that BJ-6 strain had obvious inhibitory effect on the pathogen of Sclerotinia sclerotiorum of apple and cucumber.

Is that what the last sentence meant?

Suggestion: I don't know if you are testing 5 kinds of bacteria or 5 strains. If it is five kinds of bacteria, replace BJ-6 with strain name; If it is one plant, change the front to five plants; If there are several kinds of bacteria in the five strains, write several kinds of bacteria in front and some kind of bacteria in the back, and indicate the strain number BJ-6 in brackets.