Gram-negative Bacteria on Cotton with Particular Reference to Climatic Conditions

Various factors that control the contamination of the cotton plant by Gram-negative Bacteria (GNB) were studied. The following cotton plant parts were contaminated with decreasing numbers of GNB: senescent bracts, pericarps, green bracts, seed cotton and leaves. Freezing of green cotton capsules (fruit) caused a significant increase in numbers of GNB on both bracts and seed cotton. Raw cotton derived from cotton plants harvested late in the autumn contained significantly larger numbers of GNB and higher levels of endotoxin than cotton collected early in the harvest season.