Potatoes are commonly grown all over the world. However, potato plants of any age are susceptible to certain diseases that affect the health and vigour of the plant. Wilt diseases and late blight are two causes of potato plant death.
Verticillium wilt is a common cause of plant death in potatoes, tomatoes and eggplant. This fungal disease is most severe during periods of hot weather. Symptoms associated with this disease are not always visible until a period of dry weather occurs. Some infected potato plants exhibit symptoms such as small fruit yield, stunting and discolouration of the plant stem. Symptoms are often restricted to one side of the plant. Verticillium wilt can predispose the plant to other diseases such as soft rot organism, which can cause the death of the plant.
Fusarium wilt is a fungal disease that affects tomato and potato plants. Fusarium wilt in the potato plant is caused by several different types of fungi that live in the soil. Symptoms of disease include lower leaf wilting, leaf yellowing, dieback and, eventually, plant death. One side of potato plants may show symptoms before the rest of the plant. Tubers often turn brown and streaks of dark brown are often visible in the plant stem. Wilting of lower leaves indicates root decay and the entire plant soon wilts and collapses.
Potato plants are susceptible to a serious and damaging disease known as late blight, which is caused by the fungus Phytophthora infestans. Plants of any stage of development are at risk of contracting late blight. Favourable weather conditions enable this fungal disease to spread rapidly, killing large numbers of potato plants. The symptoms associated with late blight in potato plants include lesions on lower leaves that are light green and watersoaked; these lesions quickly grow and turn black. As the lesions grow and expand, leaves become blighted and die. Tubers are also in danger of contracting late blight, which causes plants to develop purple lesions on potato skin and granular rot under the skin. Severe infection causes extensive rot in tubers and mouldy growth is often present on the tuber surface. Late blight is transmitted from plant-to-plant by spores that are carried on the wind. High moisture and mild temperatures favour the development of this fungal disease.
Premature decline in potato plants is caused by a lesion nematode, Verticillium fungus and environmental factors. This disease is characterised by the rapid decline of potato plant health, which leads to its untimely death. Treating premature decline in potato plants depends largely on the cause of decline. Planting cultivars resistant to premature decline is often effective in preventing disease development.