本试验测定了5种拮抗细菌对5种植物病原真菌的室内抑菌活性，结果发现BJ-6菌株对黄瓜菌核病菌、苹果斑点落

We tested the antiblastic effects of 5 bacterial species against pathogenic fungis causing epiphytotic. The result indicates the strain BJ-6 is distinctly effective to the pathogenies of alternaria blotch on apple and cucumber sclerotium disease.
最后一句话是这么个意思吧？
建议：不知道你是测定5种细菌还是5株菌株？如果是5种细菌，就把BJ-6替换成菌种的名字；如果是菌株，就把前面改成5株菌株；如果是5株菌株中有几种细菌，那就前面写几种细菌，后面写某种细菌加个括号注明菌株号码BJ-6。