Reaction of Amaranthus hybridus Subsp. Incurvatus to Varying Levels of Meloidogyne javanica Inoculum

Abstract

In greenhouse tests conducted to determine the host suitability of Amaranthus hybridus subsp. incurvatus L. to Meloidogyne javanica (Treub) Chitwood, eleven-day-old seedlings in pots of steam sterilized soil were inoculated with 0, 10, 100, 1000, or 10,000 second-stage larvae. Observations on growth response made 14, 28, 42, and 49 days after inoculation showed stimulated growth in inoculated plants but this effect was short-lived with the highest inoculum. Stimulated growth was reflected in significantly greater shoot heights, number of leaves per plant, length of internodes, and length and weight of inflorescences, especially in plants inoculated with 10,000 larvae per plant, according to the analysis of variance tests. Plants in the 10,000 inoculation were the first to come into flower. The weight of root systems and number of secondary roots tended to increase with an increase in the inoculum levels, but the number of primary roots was reduced. The severity of infestation increas