Impact
Potato early dying is predominately caused by the soilborne fungus Verticilium dahliae in the San Luis Valley. The disease is characterized by premature vine death and declining yields. Fields continuously cropped with potatoes are common sites of the disease. Potato early dying is rarely a problem in the San Luis Valley due to the cool environmental conditions and short growing seasons.

Descriptions and Symptoms
	Symptoms of potato early dying are difficult to distinguish from normal senescence. Infected plantst may only initially exhibit retarded growth.
	Foliar symptoms appear as uneven chlorosis and some wilting of the lower leaves.
	Areas between leaf veins turn yellow and later brown, often at the leaf tip first.
	Leaf yellowing and death proceed up the stem, which usually remains erect.
	A tan discoloration of the vascular tissues usually can be seen when a stem is cut in a cross section near its base.
	Noninfested fields can become contaminated with Verticillium carred in or on the surface of seed tubers or in soil particles transpotred by the wind or by mechanical means. Once established in a field, the fungus will persists in the soil for several years.
	Verticillium can be maintained at a low population in the roots of many; symptomless cro and weed species.
	High populations of the root-lesion nematode, Pratylenchus spp., in the presence of Verticillium can increase potato early dying.
Integrated Management
	Rotate out of potatoes for two or three years.
	Maximize yields by maintaining optimum fertility and providing adequate soil moisture to overcome the effects of Verticillium wilt in the field.
	Plant resistant cultivars. This is the most practical method for management of potato early dying. However, availability of resistant cultivars is limited.
	Avoid highly susceptible varieties which can increase the levels of Verticillium in th soil and result in higher soil inoculum levels.
	Apply soil fumigants to reduce populations of Verticillium. Fumigants do not completely eradicate the pathogen from infested fields. However, fumigation in the San Luis Valley appears to have long-term effects. Due to the high cost, base the decision to fumigate on the field history of early dying, cultivar to be grown, and on an assay of the soil to determine nematode and Verticillium populations.

This material is based on work supported by the San Luis Valley Water Quality Demonstration Project Best Management Practices Advisory Committee, Colorado State University Cooperative Extension, Farm Service Agency, Natural Resources Conservation Service, and the U.S. Department of Agriculture under authorization as 1991 U.S. Department of Agriculture Water Quality Demonstration Project.