Field experiments at Narrabri in 1993, 1994 and 1995 have utilised overhead sprinklers and, portable rain-out shelters. Results have indicated that microbial damage is initiated and, develops when mature exposed lint is subject to wet weather in the field prior to harvest., Microbial deterioration of cotton fibre continued within the module when the module moisture, was high. Techniques have been developed to apply anti-microbial substances to seed cotton, prior to producing modules and to generate different moisture contents in "mini'' modules for, storage experiments