Improve the flow of ideas for the process descriptions by adding a time adverbial, linking passive, or using an -ed participle. There may be several possibilities, but choose the best one you can. Again, redundancy in the original sentences may be dropped in your revised sentence, as long as the key ideas are conveyed.
Banana trees become infected with the banana bunchy top virus. In the early stages of the disease, the banana trees produce fruit that is deformed. Eventually, in later stages of the diseases, the plants yield no fruit at all.