Abstract
The influence of shoot and root extracts of nine plant species including Gaillardia aristata, Cosmos bipinnatus, Helianthus annuus, Tagetes erecta, Tagetes patula, Chamomilla recutita, Matricaria discoidea, Calendula officinalis and Zinnia elegans belonging to the family Asteraceae was tested towards egg hatch and mobility of Meloidogyne javanica, the root-knot nematode juveniles in vitro. In general, root extracts of the plant species were more effective in the inhibition of nematode compared to the corresponding shoot extracts. When plant species were compared, shoot extract of Z. elegans inhibited egg hatch most while shoot extract of T. erecta caused greatest mortality of M. javanica juveniles. When compared with the controls, soil amendment with Z. elegans significantly reduced M. javanica population densities in soil and subsequent root-knot development in tomato while T. erecta failed to produce such effects. Similarly, soil amendment with Z. elegans resulted in a significant increase in plant height. Whereas both amendments enhanced fresh weight of shoot compared to the controls, none of the amendments had an influence on root growth of tomato plants.
