Diagnosis of alternaria diseases on underground vegetable crops

Fourteen underground vegetables including roots, bulbs, rhizomes, corms and tubers have been observed to be infected by sixteen different species of Alternaria which cause leafs pots/blight, root rot and black rot in the field and decay, deterioration in storage. Radish, turnip and knol khol are affected by A. raphani, A. brassicae and A. brassiciola. Carrot, an underground taproot vegetable is infected by three species of Alternaria causing leaf blight and black rot. A. porri and A. alli cause purple blotch in onion, garlic and leek. On sweet potato and potato, four Alternaria spp. are involved and in case of rhizomes and corms. A. alternata of wide spread occurrence, appeared to cause the lesions, spots and blight in six underground vegetables like radish, sugarbeet, ginger, turmeric, zimikand and potato. All the sixteen species of Alternaria representing different sections of this genus differ in their morphological characteristics. Simple and suitable keys for their correct identification have been framed also where there is the involvement of more than one Alternaria species in causation of disease.