Lint within intact, unopened cotton bolls does not contain a detectable microbial flora. Contamination with microorganisms occurs shortly after boll opening. Many of the organisms extracted from the lint were detected on other parts of the plant prior to boll opening, as shown by weekly standard plate counts of the numbers of total viable bacteria and viable gram negative bacteria extracted from the roots, stems, branches, leaves, flowers, green boll carpels and bract, lint, and open boll carpels and bract. Two way analyses of variance performed on the data showed there is a significant interaction between date of sampling and plant part for both the total number of bacteria and the number of gram negative bacteria.

When differential counts of the predominant and most abundant gram negative bacteria on the lint were performed on extracts of each of the plant parts, these organisms were detected on every plant part prior to, and at, boll opening and thus could serve as a source of bacterial inoculum for the lint.