Potato Early Dying: Management Challenges in a Changing Production Environment

The potato (Solanum tuberosum L.) had its start in the Andean highlands of South America, where archeological evidence indicates it has been cultivated for at least 8,000 years (72). Today it is grown on all continents except Antarctica. Serving as a primary food source to indigenous people when the Spanish explorers arrived in Peru in the mid-1500s, the potato traveled the globe as a valuable staple, fueling armies, improving diets, and changing economies (Fig. 1). The importance of the potato goes beyond the feeding of nations, however. Today potato starch is used in the production of paper, adhesive, and textile goods, and in edible binding agents and low-fat food additives. The potato yields up a highly absorbent biodegradable material for use in disposable diapers. It provides starch products to keep oil well drilling bits smooth and to hold together the ingredients in lipsticks and cosmetic creams, and it provides a substance that works as a flocculation agent in water purification systems, replacing petroleumbased chemicals (33). China is the world’s largest producer of potatoes, followed by the Russian Federation (33). It is the most important vegetable crop in North America, where in 2000, nearly 690,000 ha were grown, with an average yield of 32.6 metric tons/ha and a farm gate value of over $2.7 billion. The potato is subject to several diseases caused by root-infecting pathogens. Two of particular significance are the soilborne fungi Verticillium dahliae and V. alboatrum. The potato root is also a host to the root-lesion nematode Pratylenchus penetrans. The two fungal pathogens alone, or in conjunction with P. penetrans, cause a disease called potato early dying (PED), also known as early die, early maturity wilt, and Verticillium wilt (64). This disease is endemic in many potato production areas of the United States, particularly in the Midwest and Pacific Northwest. In fields with a long history of potato production, it is a consistent yield constraint that requires intensive management. On land new to potato production, it may be absent in the first few years the crop is grown, but it almost invariably develops over time, requiring implementation of control measures to maintain high yields. In the last decade, the North American potato industry has undergone considerable changes. Production is increasingly being