Leaf spot of palak greens

PALAK (Beta vulgaris) is rich in nutrients. It can be cultivated throughout the year. Greens can be harvested from 45 days after sowing and subsequently every 15 days. The crop is affected by a leaf spot disease caused by cercospora beticola. Primary infection appears as small dots on marginal leaves and develop into round, depressed spots surrounded by a brown halo. At adequate relative humidity, the spots become covered with an irregular grey coat of conidia from nearly black conidiophors.

Seed crops may also be invaded from the base of the plant upto the bracts and seeds. In this case, seed germination can be partially impaired and there is a risk of seed transmission. Inoculum is conserved and dispersed by: 1) pseudo-stromata forming on seeds and surviving 20-32 months, 2) spread from seed crops to nearby ordinary crops, which is a major means of carry over from one year to the next, 3) sclerotia-bearing debris in the soil, which, like seeds, can carry the disease for over 2 years.

The disease can be controlled by spraying with copper oxychloride or mancozeb at 2 g/1 or thiabendazole at 1 g/1 five days after each harvest.

K. Rajappan, B. Ramaraj

& S. B. Nirmal Johnson

Horticultural Research Station

Udhagamandalam 643 001

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