An attractive appearance is crucial in the marketing of table potatoes. A clean, shiny, bright-coloured skin free of diseases or other defects is desired in red-skinned cultivars such as Norland, Pontiac and Peregrine. Unfortunately a range of diseases and disorders can interfere with the appearance of red-skinned potatoes. In some years russeting of the skin is one of the most common quality complaints facing growers of red-skinned potatoes. While a russeted skin is an inherited trait in some potato cultivars such as Netted Gem and Ranger Russet, the development of a russeted skin in red-skinned cultivars is regarded as an undesirable abnormality. Russeting of red-skinned varieties is usually superficial and restricted to a few patchy areas on the surface of the tuber, while on standard russeted varieties the entire surface of the tuber is covered with a fairly thick layer of russeted tissue. Russeting of red-skinned potatoes can start fairly soon after tuber set but increases in incidence and severity throughout the growing season. More