Attactiveness of Meloidogyne incognita larvae to roots of tomato anf changes in biochemical content of plants as affected by oil cakes and nematicides

Abstract

Oilcake organic amendments have proved to be effective in controlling plant parasitic nematodes on many different crops (Khan et al., 1974; Singh and Sitaramaiah, 1971; Singh et al., 1979). The mechanism of control is not fully understood but several theories have been advanced, including an increase in predaceous activity of microorganisms in the amended soil (Linford and Oliveira, 1937), release of toxic substances during decomposition of organic matter (Sayre, 1971) and the acquisition of increased resistance by the plant (Giebel, 1974). Singh et al. (1980) have attempted to reduce the economic cost of treatment by coating the seeds with oilcakes and obtained a level of nematode control almost equal to that obtained by the usual soil amendment. It, therefore, seemed appropriate to find out how nematodes behave in the presence of oilcake-coated seeds and the effect on the biochemistry of the plants grown from such treated seeds. Specifically, the present study examined the relative attractiveness of roots of tomato cv. Marglobe seedlings, grown from seeds treated with oilcakes, to the larvae of Meloidogyne incognita (Kofoid et White) Chitw. and the changes in the phenolic and aminoacid content of the seedlings. Comparative treatments were made with several nematicides.