The Problem Cotton aphid and silverleaf whitefly feed on phloem sap and produce sugar rich honeydew that can contaminate open cotton bolls leading to downstream problems with processing. Despite established management strategies for these pests honeydew contaminated crops still occur. The factors that may reduce honeydew in the field include moisture (rainfall), sunlight (UV radiation) and microorganisms (sooty mould fungi). Our experiments aim to establish the importance and effectiveness of each factor in reducing honeydew to levels that are safe to harvest.