SOME STUDIES ON THE BIOLOGY OF MELOIDOGYNE JAVANICA (TREUB, 1885) OCCURRING IN CARICA PAPAYA LINN

Abstract

Some aspects on the biology of Meloidogyne javanica (Treub, 1885) parasitising Carica papaya Linn were studied . The taxonomic importance of the perineal pattern of the adult female and characters of the 2nd larval stage were examined and found useful . The parasite caused gall formation mostly in lateral and tertiary roots, and preferred sandy and loamy (loose humus ) soils. Its life cycle consisted of the egg, 1st, 2nd, 3rd and 4th larval stages, and the adult. Each stage was examined and discussed. Embryonic development of M. javanica was found to be rapid. In the Growth Curve experiment, the 2nd larval stage failed to moult and became very large if prevented from entering root tissues . Vertical and horizontal distributions of the 2nd larval stage was affected by changes in soil temperature, soil moisture level, soil size and root distribution. Changes in soil temperature resulted in vertical migration of the larvae. The effect of the parasite on the host was also discussed.