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The root-knot nematodes (Meloidogyne species) are economically important pathogens, especially infesting vegetable crops. In the tropics and subtropics, Meloidogyne incognita causes an estimated yield loss of 5 to 43% in vegetable crops. In the present study, root-knot nematode disease was surveyed in various vegetable crops in the central plain region of Chhattisgarh State. Roots and rhizosphere soil samples were collected from 44 farmlands representing five districts of Chhattisgarh during mid cropping season. Nematodes were extracted by Cobb's sieving and decanting method, followed by modified Baermann's funnel technique. Out of 44 samples, 24 showed the root-knot nematodes infection with an overall incidence of 54.54%. The percent incidences of disease ranged between 30 and 80% in five districts. Out of 13 species of vegetable crops surveyed, nine were observed to be infected. The most frequently occurring species was Meloidogyne incognita (63.33%), followed by Meloidogyne arenaria (20%) and Meloidogyne javanica (16.67%). Maximum frequency was observed in Lageneria siceraria (100%), and least was Musa paradisiaca, Daucus carota and Amaranthus tristis (50%). The mean population density of 2 nd stage nematodes ranged between 766 and 9076 nematodes/200 cc soil and 10 g roots in samples.

Root knot nematodes (Meloidogyne species) are major pests of vegetable crops causing serious losses in quantity and quality of crop yield. This study involves an assessment of their suitable hosts on the basis of variations in their population densities and body sizes in different vegetable crop plants under field conditions. A random survey of root knot nematode infestation in vegetable crops was conducted in 9 villages of Abhanpur block, Chhattisgarh state, Central India, from January 2012 to March 2012.  Diseased plants were identified on the basis of above ground symptoms and soil and root samples collected by digging. Extraction of nematodes was done by Cobb’s sieving and decantation method and Baerman’s funnel technique. Identification was done microscopically by morphological examination of perineal patterns of female nematodes. Body sizes were measured by using an eyepiece/ocular micrometer. Twenty nine percent of the total farm area surveyed suffered from root knot nematode attack. Among the several genera of vegetable crop plants surveyed, Lycopersicon esculentum, Dolichos lablab, Solanum melongena, Momordica charantia, Daucus carota,Capsicum annum,Cucumis sativus had root galls. Three species of root knot nematodes Meloidogyne incognita, M. javanica, M. areneria were identified from the above hosts and a comparative morphometric analysis of the body, head and neck size ratios of females were done. Non-significant body and head size variations existing between the females from D. lablab, S. melongena, C. annum, D. carota, L. esculentum showed that all the crops are equally susceptible to root knot nematode attack.  However, on the basis of nematode population density, D. carrota appears to be the best suitable host of the Meloidogyne species other than L. esculentum and S. melongena.

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