Sampling of cotton and bracts were done once a week throughout the growing season at Texas Tech (Lubbock), Texas A & M (College Station, Mississippi State (Starksville) and Caolifornia State (Fresno). Cottons were studied separately for each of the sixteen sectors and the bracts were pooled, dried and shipped to our laboratory for endotoxin determinations by the limulus amoebocyte lysate test.

Endotoxin content rapidly reached a high level and remained stable throughout most of the growing season. Samples from California were much lower in endotoxin. The phylloplane microbial load is similar in microorganisms for all four sites, but singificantly lower for California. This is the second year of a three year study.